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<section id="arrow-flight-rpc">
<span id="flight-rpc"></span><h1>Arrow Flight RPC<a class="headerlink" href="#arrow-flight-rpc" title="Permalink to this heading">#</a></h1>
<p>Arrow Flight is an RPC framework for high-performance data services
based on Arrow data, and is built on top of <a class="reference external" href="https://grpc.io/">gRPC</a> and the <a class="reference internal" href="IPC.html"><span class="doc">IPC
format</span></a>.</p>
<p>Flight is organized around streams of Arrow record batches, being
either downloaded from or uploaded to another service. A set of
metadata methods offers discovery and introspection of streams, as
well as the ability to implement application-specific methods.</p>
<p>Methods and message wire formats are defined by <a class="reference external" href="https://developers.google.com/protocol-buffers/">Protobuf</a>, enabling
interoperability with clients that may support gRPC and Arrow
separately, but not Flight. However, Flight implementations include
further optimizations to avoid overhead in usage of Protobuf (mostly
around avoiding excessive memory copies).</p>
<section id="rpc-methods-and-request-patterns">
<h2>RPC Methods and Request Patterns<a class="headerlink" href="#rpc-methods-and-request-patterns" title="Permalink to this heading">#</a></h2>
<p>Flight defines a set of RPC methods for uploading/downloading data,
retrieving metadata about a data stream, listing available data
streams, and for implementing application-specific RPC methods. A
Flight service implements some subset of these methods, while a Flight
client can call any of these methods.</p>
<p>Data streams are identified by descriptors (the <code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code>
message), which are either a path or an arbitrary binary command. For
instance, the descriptor may encode a SQL query, a path to a file on a
distributed file system, or even a pickled Python object; the
application can use this message as it sees fit.</p>
<p>Thus, one Flight client can connect to any service and perform basic
operations. To facilitate this, Flight services are <em>expected</em> to
support some common request patterns, described next. Of course,
applications may ignore compatibility and simply treat the Flight RPC
methods as low-level building blocks for their own purposes.</p>
<p>See <a class="reference internal" href="#protocol-buffer-definitions">Protocol Buffer Definitions</a> for full details on the methods and
messages involved.</p>
<section id="downloading-data">
<h3>Downloading Data<a class="headerlink" href="#downloading-data" title="Permalink to this heading">#</a></h3>
<p>A client that wishes to download the data would:</p>
<figure class="align-default" id="id1">
<img alt="../_images/DoGet.mmd.svg" src="../_images/DoGet.mmd.svg" /><figcaption>
<p><span class="caption-text">Retrieving data via <code class="docutils literal notranslate"><span class="pre">DoGet</span></code>.</span><a class="headerlink" href="#id1" title="Permalink to this image">#</a></p>
</figcaption>
</figure>
<ol class="arabic">
<li><p>Construct or acquire a <code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code> for the data set they
are interested in.</p>
<p>A client may know what descriptor they want already, or they may
use methods like <code class="docutils literal notranslate"><span class="pre">ListFlights</span></code> to discover them.</p>
</li>
<li><p>Call <code class="docutils literal notranslate"><span class="pre">GetFlightInfo(FlightDescriptor)</span></code> to get a <code class="docutils literal notranslate"><span class="pre">FlightInfo</span></code>
message.</p>
<p>Flight does not require that data live on the same server as
metadata. Hence, <code class="docutils literal notranslate"><span class="pre">FlightInfo</span></code> contains details on where the data
is located, so the client can go fetch the data from an appropriate
server. This is encoded as a series of <code class="docutils literal notranslate"><span class="pre">FlightEndpoint</span></code> messages
inside <code class="docutils literal notranslate"><span class="pre">FlightInfo</span></code>. Each endpoint represents some location that
contains a subset of the response data.</p>
<p>An endpoint contains a list of locations (server addresses) where
this data can be retrieved from, and a <code class="docutils literal notranslate"><span class="pre">Ticket</span></code>, an opaque binary
token that the server will use to identify the data being
requested.</p>
<p>If <code class="docutils literal notranslate"><span class="pre">FlightInfo.ordered</span></code> is true, this signals there is some order
between data from different endpoints. Clients should produce the
same results as if the data returned from each of the endpoints was
concatenated, in order, from front to back.</p>
<p>If <code class="docutils literal notranslate"><span class="pre">FlightInfo.ordered</span></code> is false, the client may return data
from any of the endpoints in arbitrary order. Data from any
specific endpoint must be returned in order, but the data from
different endpoints may be interleaved to allow parallel fetches.</p>
<p>Note that since some clients may ignore <code class="docutils literal notranslate"><span class="pre">FlightInfo.ordered</span></code>, if
ordering is important and client support cannot be ensured,
servers should return a single endpoint.</p>
<p>The response also contains other metadata, like the schema, and
optionally an estimate of the dataset size.</p>
</li>
<li><p>Consume each endpoint returned by the server.</p>
<p>To consume an endpoint, the client should connect to one of the
locations in the endpoint, then call <code class="docutils literal notranslate"><span class="pre">DoGet(Ticket)</span></code> with the
ticket in the endpoint. This will give the client a stream of Arrow
record batches.</p>
<p>If the server wishes to indicate that the data is on the local
server and not a different location, then it can return an empty
list of locations. The client can then reuse the existing
connection to the original server to fetch data. Otherwise, the
client must connect to one of the indicated locations.</p>
<p>The server may list “itself” as a location alongside other server
locations. Normally this requires the server to know its public
address, but it may also use the special URI string
<code class="docutils literal notranslate"><span class="pre">arrow-flight-reuse-connection://?</span></code> to tell clients that they may
reuse an existing connection to the same server, without having to
be able to name itself. See <a class="reference internal" href="#connection-reuse">Connection Reuse</a> below.</p>
<p>In this way, the locations inside an endpoint can also be thought
of as performing look-aside load balancing or service discovery
functions. And the endpoints can represent data that is partitioned
or otherwise distributed.</p>
<p>The client must consume all endpoints to retrieve the complete data
set. The client can consume endpoints in any order, or even in
parallel, or distribute the endpoints among multiple machines for
consumption; this is up to the application to implement. The client
can also use <code class="docutils literal notranslate"><span class="pre">FlightInfo.ordered</span></code>. See the previous item for
details of <code class="docutils literal notranslate"><span class="pre">FlightInfo.ordered</span></code>.</p>
<p>Each endpoint may have expiration time
(<code class="docutils literal notranslate"><span class="pre">FlightEndpoint.expiration_time</span></code>). If an endpoint has expiration
time, the client can get data multiple times by <code class="docutils literal notranslate"><span class="pre">DoGet</span></code> until the
expiration time is reached. Otherwise, it is application-defined
whether <code class="docutils literal notranslate"><span class="pre">DoGet</span></code> requests may be retried. The expiration time is
represented as <a class="reference external" href="https://protobuf.dev/reference/protobuf/google.protobuf/#timestamp">google.protobuf.Timestamp</a>.</p>
<p>If the expiration time is short, the client may be able to extend
the expiration time by <code class="docutils literal notranslate"><span class="pre">RenewFlightEndpoint</span></code> action. The client
need to use <code class="docutils literal notranslate"><span class="pre">DoAction</span></code> with <code class="docutils literal notranslate"><span class="pre">RenewFlightEndpoint</span></code> action type
to extend the expiration time. <code class="docutils literal notranslate"><span class="pre">Action.body</span></code> must be
<code class="docutils literal notranslate"><span class="pre">RenewFlightEndpointRequest</span></code> that has <code class="docutils literal notranslate"><span class="pre">FlightEndpoint</span></code> to be
renewed.</p>
<p>The client may be able to cancel the returned <code class="docutils literal notranslate"><span class="pre">FlightInfo</span></code> by
<code class="docutils literal notranslate"><span class="pre">CancelFlightInfo</span></code> action. The client need to use <code class="docutils literal notranslate"><span class="pre">DoAction</span></code>
with <code class="docutils literal notranslate"><span class="pre">CancelFlightInfo</span></code> action type to cancel the <code class="docutils literal notranslate"><span class="pre">FlightInfo</span></code>.</p>
</li>
</ol>
</section>
<section id="downloading-data-by-running-a-heavy-query">
<h3>Downloading Data by Running a Heavy Query<a class="headerlink" href="#downloading-data-by-running-a-heavy-query" title="Permalink to this heading">#</a></h3>
<p>A client may need to request a heavy query to download
data. However, <code class="docutils literal notranslate"><span class="pre">GetFlightInfo</span></code> doesn’t return until the query
completes, so the client is blocked. In this situation, the client
can use <code class="docutils literal notranslate"><span class="pre">PollFlightInfo</span></code> instead of <code class="docutils literal notranslate"><span class="pre">GetFlightInfo</span></code>:</p>
<figure class="align-default" id="id2">
<img alt="../_images/PollFlightInfo.mmd.svg" src="../_images/PollFlightInfo.mmd.svg" /><figcaption>
<p><span class="caption-text">Polling a long-running query by <code class="docutils literal notranslate"><span class="pre">PollFlightInfo</span></code>.</span><a class="headerlink" href="#id2" title="Permalink to this image">#</a></p>
</figcaption>
</figure>
<ol class="arabic">
<li><p>Construct or acquire a <code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code>, as before.</p></li>
<li><p>Call <code class="docutils literal notranslate"><span class="pre">PollFlightInfo(FlightDescriptor)</span></code> to get a <code class="docutils literal notranslate"><span class="pre">PollInfo</span></code>
message.</p>
<p>A server should respond as quickly as possible on the first
call. So the client shouldn’t wait for the first <code class="docutils literal notranslate"><span class="pre">PollInfo</span></code>
response.</p>
<p>If the query isn’t finished, <code class="docutils literal notranslate"><span class="pre">PollInfo.flight_descriptor</span></code> has a
<code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code>. The client should use the descriptor (not the
original <code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code>) to call the next
<code class="docutils literal notranslate"><span class="pre">PollFlightInfo()</span></code>. A server should recognize a
<code class="docutils literal notranslate"><span class="pre">PollInfo.flight_descriptor</span></code> that is not necessarily the latest
in case the client misses an update in between.</p>
<p>If the query is finished, <code class="docutils literal notranslate"><span class="pre">PollInfo.flight_descriptor</span></code> is
unset.</p>
<p><code class="docutils literal notranslate"><span class="pre">PollInfo.info</span></code> is the currently available results so far. It’s
a complete <code class="docutils literal notranslate"><span class="pre">FlightInfo</span></code> each time not just the delta between the
previous and current <code class="docutils literal notranslate"><span class="pre">FlightInfo</span></code>. A server should only append to
the endpoints in <code class="docutils literal notranslate"><span class="pre">PollInfo.info</span></code> each time. So the client can
run <code class="docutils literal notranslate"><span class="pre">DoGet(Ticket)</span></code> with the <code class="docutils literal notranslate"><span class="pre">Ticket</span></code> in the <code class="docutils literal notranslate"><span class="pre">PollInfo.info</span></code>
even when the query isn’t finished yet. <code class="docutils literal notranslate"><span class="pre">FlightInfo.ordered</span></code> is
also valid.</p>
<p>A server should not respond until the result would be different
from last time. That way, the client can “long poll” for updates
without constantly making requests. Clients can set a short timeout
to avoid blocking calls if desired.</p>
<p><code class="docutils literal notranslate"><span class="pre">PollInfo.progress</span></code> may be set. It represents progress of the
query. If it’s set, the value must be in <code class="docutils literal notranslate"><span class="pre">[0.0,</span> <span class="pre">1.0]</span></code>. The value
is not necessarily monotonic or nondecreasing. A server may respond by
only updating the <code class="docutils literal notranslate"><span class="pre">PollInfo.progress</span></code> value, though it shouldn’t
spam the client with updates.</p>
<p><code class="docutils literal notranslate"><span class="pre">PollInfo.timestamp</span></code> is the expiration time for this
request. After this passes, a server might not accept the poll
descriptor anymore and the query may be cancelled. This may be
updated on a call to <code class="docutils literal notranslate"><span class="pre">PollFlightInfo</span></code>. The expiration time is
represented as <a class="reference external" href="https://protobuf.dev/reference/protobuf/google.protobuf/#timestamp">google.protobuf.Timestamp</a>.</p>
<p>A client may be able to cancel the query by the
<code class="docutils literal notranslate"><span class="pre">CancelFlightInfo</span></code> action.</p>
<p>A server should return an error status instead of a response if the
query fails. The client should not poll the request except for
<code class="docutils literal notranslate"><span class="pre">TIMED_OUT</span></code> and <code class="docutils literal notranslate"><span class="pre">UNAVAILABLE</span></code>, which may not originate from the
server.</p>
</li>
<li><p>Consume each endpoint returned by the server, as before.</p></li>
</ol>
</section>
<section id="uploading-data">
<h3>Uploading Data<a class="headerlink" href="#uploading-data" title="Permalink to this heading">#</a></h3>
<p>To upload data, a client would:</p>
<figure class="align-default" id="id3">
<img alt="../_images/DoPut.mmd.svg" src="../_images/DoPut.mmd.svg" /><figcaption>
<p><span class="caption-text">Uploading data via <code class="docutils literal notranslate"><span class="pre">DoPut</span></code>.</span><a class="headerlink" href="#id3" title="Permalink to this image">#</a></p>
</figcaption>
</figure>
<ol class="arabic">
<li><p>Construct or acquire a <code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code>, as before.</p></li>
<li><p>Call <code class="docutils literal notranslate"><span class="pre">DoPut(FlightData)</span></code> and upload a stream of Arrow record
batches.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code> is included with the first message so the
server can identify the dataset.</p>
</li>
</ol>
<p><code class="docutils literal notranslate"><span class="pre">DoPut</span></code> allows the server to send response messages back to the
client with custom metadata. This can be used to implement things like
resumable writes (e.g. the server can periodically send a message
indicating how many rows have been committed so far).</p>
</section>
<section id="exchanging-data">
<h3>Exchanging Data<a class="headerlink" href="#exchanging-data" title="Permalink to this heading">#</a></h3>
<p>Some use cases may require uploading and downloading data within a
single call. While this can be emulated with multiple calls, this may
be difficult if the application is stateful. For instance, the
application may wish to implement a call where the client uploads data
and the server responds with a transformation of that data; this would
require being stateful if implemented using <code class="docutils literal notranslate"><span class="pre">DoGet</span></code> and
<code class="docutils literal notranslate"><span class="pre">DoPut</span></code>. Instead, <code class="docutils literal notranslate"><span class="pre">DoExchange</span></code> allows this to be implemented as a
single call. A client would:</p>
<figure class="align-default" id="id4">
<img alt="../_images/DoExchange.mmd.svg" src="../_images/DoExchange.mmd.svg" /><figcaption>
<p><span class="caption-text">Complex data flow with <code class="docutils literal notranslate"><span class="pre">DoExchange</span></code>.</span><a class="headerlink" href="#id4" title="Permalink to this image">#</a></p>
</figcaption>
</figure>
<ol class="arabic">
<li><p>Construct or acquire a <code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code>, as before.</p></li>
<li><p>Call <code class="docutils literal notranslate"><span class="pre">DoExchange(FlightData)</span></code>.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">FlightDescriptor</span></code> is included with the first message, as
with <code class="docutils literal notranslate"><span class="pre">DoPut</span></code>. At this point, both the client and the server may
simultaneously stream data to the other side.</p>
</li>
</ol>
</section>
</section>
<section id="authentication">
<h2>Authentication<a class="headerlink" href="#authentication" title="Permalink to this heading">#</a></h2>
<p>Flight supports a variety of authentication methods that applications
can customize for their needs.</p>
<dl>
<dt>“Handshake” authentication</dt><dd><p>This is implemented in two parts. At connection time, the client
calls the <code class="docutils literal notranslate"><span class="pre">Handshake</span></code> RPC method, and the application-defined
authentication handler can exchange any number of messages with its
counterpart on the server. The handler then provides a binary
token. The Flight client will then include this token in the headers
of all future calls, which is validated by the server authentication
handler.</p>
<p>Applications may use any part of this; for instance, they may ignore
the initial handshake and send an externally acquired token (e.g. a
bearer token) on each call, or they may establish trust during the
handshake and not validate a token for each call, treating the
connection as stateful (a “login” pattern).</p>
<div class="admonition warning">
<p class="admonition-title">Warning</p>
<p>Unless a token is validated on every call, this pattern
is not secure, especially in the presence of a layer
7 load balancer, as is common with gRPC, or if gRPC
transparently reconnects the client.</p>
</div>
</dd>
<dt>Header-based/middleware-based authentication</dt><dd><p>Clients may include custom headers with calls. Custom middleware can
then be implemented to validate and accept/reject calls on the
server side.</p>
</dd>
<dt><a class="reference external" href="https://grpc.io/docs/guides/auth/#supported-auth-mechanisms">Mutual TLS (mTLS)</a></dt><dd><p>The client provides a certificate during connection establishment
which is verified by the server. The application does not need to
implement any authentication code, but must provision and distribute
certificates.</p>
<p>This may only be available in certain implementations, and is only
available when TLS is also enabled.</p>
</dd>
</dl>
<p>Some Flight implementations may expose the underlying gRPC API as
well, in which case any <a class="reference external" href="https://grpc.io/docs/guides/auth/">authentication method supported by gRPC</a> is available.</p>
</section>
<section id="location-uris">
<h2>Location URIs<a class="headerlink" href="#location-uris" title="Permalink to this heading">#</a></h2>
<p>Flight is primarily defined in terms of its Protobuf and gRPC
specification below, but Arrow implementations may also support
alternative transports (see <a class="reference internal" href="../status.html#status-flight-rpc"><span class="std std-ref">Flight RPC</span></a>). Clients and
servers need to know which transport to use for a given URI in a
Location, so Flight implementations should use the following URI
schemes for the given transports:</p>
<table class="table">
<thead>
<tr class="row-odd"><th class="head"><p>Transport</p></th>
<th class="head"><p>URI Scheme</p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><p>gRPC (plaintext)</p></td>
<td><p>grpc: or grpc+tcp:</p></td>
</tr>
<tr class="row-odd"><td><p>gRPC (TLS)</p></td>
<td><p>grpc+tls:</p></td>
</tr>
<tr class="row-even"><td><p>gRPC (Unix domain socket)</p></td>
<td><p>grpc+unix:</p></td>
</tr>
<tr class="row-odd"><td><p>(reuse connection)</p></td>
<td><p>arrow-flight-reuse-connection:</p></td>
</tr>
<tr class="row-even"><td><p><a class="reference external" href="https://openucx.org/">UCX</a> (plaintext)</p></td>
<td><p>ucx:</p></td>
</tr>
</tbody>
</table>
<section id="connection-reuse">
<h3>Connection Reuse<a class="headerlink" href="#connection-reuse" title="Permalink to this heading">#</a></h3>
<p>“Reuse connection” above is not a particular transport. Instead, it
means that the client may try to execute DoGet against the same server
(and through the same connection) that it originally obtained the
FlightInfo from (i.e., that it called GetFlightInfo against). This is
interpreted the same way as when no specific <code class="docutils literal notranslate"><span class="pre">Location</span></code> are
returned.</p>
<p>This allows the server to return “itself” as one possible location to
fetch data without having to know its own public address, which can be
useful in deployments where knowing this would be difficult or
impossible. For example, a developer may forward a remote service in
a cloud environment to their local machine; in this case, the remote
service would have no way to know the local hostname and port that it
is being accessed over.</p>
<p>For compatibility reasons, the URI should always be
<code class="docutils literal notranslate"><span class="pre">arrow-flight-reuse-connection://?</span></code>, with the trailing empty query
string. Java’s URI implementation does not accept <code class="docutils literal notranslate"><span class="pre">scheme:</span></code> or
<code class="docutils literal notranslate"><span class="pre">scheme://</span></code>, and C++’s implementation does not accept an empty
string, so the obvious candidates are not compatible. The chosen
representation can be parsed by both implementations, as well as Go’s
<code class="docutils literal notranslate"><span class="pre">net/url</span></code> and Python’s <code class="docutils literal notranslate"><span class="pre">urllib.parse</span></code>.</p>
</section>
</section>
<section id="error-handling">
<h2>Error Handling<a class="headerlink" href="#error-handling" title="Permalink to this heading">#</a></h2>
<p>Arrow Flight defines its own set of error codes. The implementation
differs between languages (e.g. in C++, Unimplemented is a general
Arrow error status while it’s a Flight-specific exception in Java),
but the following set is exposed:</p>
<table class="table">
<thead>
<tr class="row-odd"><th class="head"><p>Error Code</p></th>
<th class="head"><p>Description</p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><p>UNKNOWN</p></td>
<td><p>An unknown error. The default if no other
error applies.</p></td>
</tr>
<tr class="row-odd"><td><p>INTERNAL</p></td>
<td><p>An error internal to the service
implementation occurred.</p></td>
</tr>
<tr class="row-even"><td><p>INVALID_ARGUMENT</p></td>
<td><p>The client passed an invalid argument to
the RPC.</p></td>
</tr>
<tr class="row-odd"><td><p>TIMED_OUT</p></td>
<td><p>The operation exceeded a timeout or
deadline.</p></td>
</tr>
<tr class="row-even"><td><p>NOT_FOUND</p></td>
<td><p>The requested resource (action, data
stream) was not found.</p></td>
</tr>
<tr class="row-odd"><td><p>ALREADY_EXISTS</p></td>
<td><p>The resource already exists.</p></td>
</tr>
<tr class="row-even"><td><p>CANCELLED</p></td>
<td><p>The operation was cancelled (either by the
client or the server).</p></td>
</tr>
<tr class="row-odd"><td><p>UNAUTHENTICATED</p></td>
<td><p>The client is not authenticated.</p></td>
</tr>
<tr class="row-even"><td><p>UNAUTHORIZED</p></td>
<td><p>The client is authenticated, but does not
have permissions for the requested
operation.</p></td>
</tr>
<tr class="row-odd"><td><p>UNIMPLEMENTED</p></td>
<td><p>The RPC is not implemented.</p></td>
</tr>
<tr class="row-even"><td><p>UNAVAILABLE</p></td>
<td><p>The server is not available. May be emitted
by the client for connectivity reasons.</p></td>
</tr>
</tbody>
</table>
</section>
<section id="external-resources">
<h2>External Resources<a class="headerlink" href="#external-resources" title="Permalink to this heading">#</a></h2>
<ul class="simple">
<li><p><a class="reference external" href="https://arrow.apache.org/blog/2019/10/13/introducing-arrow-flight/">https://arrow.apache.org/blog/2019/10/13/introducing-arrow-flight/</a></p></li>
<li><p><a class="reference external" href="https://arrow.apache.org/blog/2018/10/09/0.11.0-release/">https://arrow.apache.org/blog/2018/10/09/0.11.0-release/</a></p></li>
<li><p><a class="reference external" href="https://www.slideshare.net/JacquesNadeau5/apache-arrow-flight-overview">https://www.slideshare.net/JacquesNadeau5/apache-arrow-flight-overview</a></p></li>
</ul>
</section>
<section id="protocol-buffer-definitions">
<h2>Protocol Buffer Definitions<a class="headerlink" href="#protocol-buffer-definitions" title="Permalink to this heading">#</a></h2>
<div class="highlight-protobuf notranslate"><div class="highlight"><pre><span></span><span class="linenos"> 1</span><span class="cm">/*</span>
<span class="linenos"> 2</span><span class="cm"> * Licensed to the Apache Software Foundation (ASF) under one</span>
<span class="linenos"> 3</span><span class="cm"> * or more contributor license agreements. See the NOTICE file</span>
<span class="linenos"> 4</span><span class="cm"> * distributed with this work for additional information</span>
<span class="linenos"> 5</span><span class="cm"> * regarding copyright ownership. The ASF licenses this file</span>
<span class="linenos"> 6</span><span class="cm"> * to you under the Apache License, Version 2.0 (the</span>
<span class="linenos"> 7</span><span class="cm"> * &quot;License&quot;); you may not use this file except in compliance</span>
<span class="linenos"> 8</span><span class="cm"> * with the License. You may obtain a copy of the License at</span>
<span class="linenos"> 9</span><span class="cm"> * &lt;p&gt;</span>
<span class="linenos"> 10</span><span class="cm"> * http://www.apache.org/licenses/LICENSE-2.0</span>
<span class="linenos"> 11</span><span class="cm"> * &lt;p&gt;</span>
<span class="linenos"> 12</span><span class="cm"> * Unless required by applicable law or agreed to in writing, software</span>
<span class="linenos"> 13</span><span class="cm"> * distributed under the License is distributed on an &quot;AS IS&quot; BASIS,</span>
<span class="linenos"> 14</span><span class="cm"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
<span class="linenos"> 15</span><span class="cm"> * See the License for the specific language governing permissions and</span>
<span class="linenos"> 16</span><span class="cm"> * limitations under the License.</span>
<span class="linenos"> 17</span><span class="cm"> */</span>
<span class="linenos"> 18</span>
<span class="linenos"> 19</span><span class="k">syntax</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;proto3&quot;</span><span class="p">;</span>
<span class="linenos"> 20</span><span class="k">import</span><span class="w"> </span><span class="s">&quot;google/protobuf/timestamp.proto&quot;</span><span class="p">;</span>
<span class="linenos"> 21</span>
<span class="linenos"> 22</span><span class="k">option</span><span class="w"> </span><span class="na">java_package</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;org.apache.arrow.flight.impl&quot;</span><span class="p">;</span>
<span class="linenos"> 23</span><span class="k">option</span><span class="w"> </span><span class="na">go_package</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;github.com/apache/arrow/go/arrow/flight/gen/flight&quot;</span><span class="p">;</span>
<span class="linenos"> 24</span><span class="k">option</span><span class="w"> </span><span class="na">csharp_namespace</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;Apache.Arrow.Flight.Protocol&quot;</span><span class="p">;</span>
<span class="linenos"> 25</span>
<span class="linenos"> 26</span><span class="kn">package</span><span class="w"> </span><span class="nn">arrow</span><span class="o">.</span><span class="n">flight.protocol</span><span class="p">;</span>
<span class="linenos"> 27</span>
<span class="linenos"> 28</span><span class="cm">/*</span>
<span class="linenos"> 29</span><span class="cm"> * A flight service is an endpoint for retrieving or storing Arrow data. A</span>
<span class="linenos"> 30</span><span class="cm"> * flight service can expose one or more predefined endpoints that can be</span>
<span class="linenos"> 31</span><span class="cm"> * accessed using the Arrow Flight Protocol. Additionally, a flight service</span>
<span class="linenos"> 32</span><span class="cm"> * can expose a set of actions that are available.</span>
<span class="linenos"> 33</span><span class="cm"> */</span>
<span class="linenos"> 34</span><span class="kd">service</span><span class="w"> </span><span class="n">FlightService</span><span class="w"> </span><span class="p">{</span>
<span class="linenos"> 35</span>
<span class="linenos"> 36</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos"> 37</span><span class="cm"> * Handshake between client and server. Depending on the server, the</span>
<span class="linenos"> 38</span><span class="cm"> * handshake may be required to determine the token that should be used for</span>
<span class="linenos"> 39</span><span class="cm"> * future operations. Both request and response are streams to allow multiple</span>
<span class="linenos"> 40</span><span class="cm"> * round-trips depending on auth mechanism.</span>
<span class="linenos"> 41</span><span class="cm"> */</span>
<span class="linenos"> 42</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">Handshake</span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">HandshakeRequest</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">HandshakeResponse</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos"> 43</span>
<span class="linenos"> 44</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos"> 45</span><span class="cm"> * Get a list of available streams given a particular criteria. Most flight</span>
<span class="linenos"> 46</span><span class="cm"> * services will expose one or more streams that are readily available for</span>
<span class="linenos"> 47</span><span class="cm"> * retrieval. This api allows listing the streams available for</span>
<span class="linenos"> 48</span><span class="cm"> * consumption. A user can also provide a criteria. The criteria can limit</span>
<span class="linenos"> 49</span><span class="cm"> * the subset of streams that can be listed via this interface. Each flight</span>
<span class="linenos"> 50</span><span class="cm"> * service allows its own definition of how to consume criteria.</span>
<span class="linenos"> 51</span><span class="cm"> */</span>
<span class="linenos"> 52</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">ListFlights</span><span class="p">(</span><span class="n">Criteria</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">FlightInfo</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos"> 53</span>
<span class="linenos"> 54</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos"> 55</span><span class="cm"> * For a given FlightDescriptor, get information about how the flight can be</span>
<span class="linenos"> 56</span><span class="cm"> * consumed. This is a useful interface if the consumer of the interface</span>
<span class="linenos"> 57</span><span class="cm"> * already can identify the specific flight to consume. This interface can</span>
<span class="linenos"> 58</span><span class="cm"> * also allow a consumer to generate a flight stream through a specified</span>
<span class="linenos"> 59</span><span class="cm"> * descriptor. For example, a flight descriptor might be something that</span>
<span class="linenos"> 60</span><span class="cm"> * includes a SQL statement or a Pickled Python operation that will be</span>
<span class="linenos"> 61</span><span class="cm"> * executed. In those cases, the descriptor will not be previously available</span>
<span class="linenos"> 62</span><span class="cm"> * within the list of available streams provided by ListFlights but will be</span>
<span class="linenos"> 63</span><span class="cm"> * available for consumption for the duration defined by the specific flight</span>
<span class="linenos"> 64</span><span class="cm"> * service.</span>
<span class="linenos"> 65</span><span class="cm"> */</span>
<span class="linenos"> 66</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">GetFlightInfo</span><span class="p">(</span><span class="n">FlightDescriptor</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">FlightInfo</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos"> 67</span>
<span class="linenos"> 68</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos"> 69</span><span class="cm"> * For a given FlightDescriptor, start a query and get information</span>
<span class="linenos"> 70</span><span class="cm"> * to poll its execution status. This is a useful interface if the</span>
<span class="linenos"> 71</span><span class="cm"> * query may be a long-running query. The first PollFlightInfo call</span>
<span class="linenos"> 72</span><span class="cm"> * should return as quickly as possible. (GetFlightInfo doesn&#39;t</span>
<span class="linenos"> 73</span><span class="cm"> * return until the query is complete.)</span>
<span class="linenos"> 74</span><span class="cm"> *</span>
<span class="linenos"> 75</span><span class="cm"> * A client can consume any available results before</span>
<span class="linenos"> 76</span><span class="cm"> * the query is completed. See PollInfo.info for details.</span>
<span class="linenos"> 77</span><span class="cm"> *</span>
<span class="linenos"> 78</span><span class="cm"> * A client can poll the updated query status by calling</span>
<span class="linenos"> 79</span><span class="cm"> * PollFlightInfo() with PollInfo.flight_descriptor. A server</span>
<span class="linenos"> 80</span><span class="cm"> * should not respond until the result would be different from last</span>
<span class="linenos"> 81</span><span class="cm"> * time. That way, the client can &quot;long poll&quot; for updates</span>
<span class="linenos"> 82</span><span class="cm"> * without constantly making requests. Clients can set a short timeout</span>
<span class="linenos"> 83</span><span class="cm"> * to avoid blocking calls if desired.</span>
<span class="linenos"> 84</span><span class="cm"> *</span>
<span class="linenos"> 85</span><span class="cm"> * A client can&#39;t use PollInfo.flight_descriptor after</span>
<span class="linenos"> 86</span><span class="cm"> * PollInfo.expiration_time passes. A server might not accept the</span>
<span class="linenos"> 87</span><span class="cm"> * retry descriptor anymore and the query may be cancelled.</span>
<span class="linenos"> 88</span><span class="cm"> *</span>
<span class="linenos"> 89</span><span class="cm"> * A client may use the CancelFlightInfo action with</span>
<span class="linenos"> 90</span><span class="cm"> * PollInfo.info to cancel the running query.</span>
<span class="linenos"> 91</span><span class="cm"> */</span>
<span class="linenos"> 92</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">PollFlightInfo</span><span class="p">(</span><span class="n">FlightDescriptor</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">PollInfo</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos"> 93</span>
<span class="linenos"> 94</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos"> 95</span><span class="cm"> * For a given FlightDescriptor, get the Schema as described in Schema.fbs::Schema</span>
<span class="linenos"> 96</span><span class="cm"> * This is used when a consumer needs the Schema of flight stream. Similar to</span>
<span class="linenos"> 97</span><span class="cm"> * GetFlightInfo this interface may generate a new flight that was not previously</span>
<span class="linenos"> 98</span><span class="cm"> * available in ListFlights.</span>
<span class="linenos"> 99</span><span class="cm"> */</span>
<span class="linenos">100</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">GetSchema</span><span class="p">(</span><span class="n">FlightDescriptor</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">SchemaResult</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos">101</span>
<span class="linenos">102</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">103</span><span class="cm"> * Retrieve a single stream associated with a particular descriptor</span>
<span class="linenos">104</span><span class="cm"> * associated with the referenced ticket. A Flight can be composed of one or</span>
<span class="linenos">105</span><span class="cm"> * more streams where each stream can be retrieved using a separate opaque</span>
<span class="linenos">106</span><span class="cm"> * ticket that the flight service uses for managing a collection of streams.</span>
<span class="linenos">107</span><span class="cm"> */</span>
<span class="linenos">108</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">DoGet</span><span class="p">(</span><span class="n">Ticket</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">FlightData</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos">109</span>
<span class="linenos">110</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">111</span><span class="cm"> * Push a stream to the flight service associated with a particular</span>
<span class="linenos">112</span><span class="cm"> * flight stream. This allows a client of a flight service to upload a stream</span>
<span class="linenos">113</span><span class="cm"> * of data. Depending on the particular flight service, a client consumer</span>
<span class="linenos">114</span><span class="cm"> * could be allowed to upload a single stream per descriptor or an unlimited</span>
<span class="linenos">115</span><span class="cm"> * number. In the latter, the service might implement a &#39;seal&#39; action that</span>
<span class="linenos">116</span><span class="cm"> * can be applied to a descriptor once all streams are uploaded.</span>
<span class="linenos">117</span><span class="cm"> */</span>
<span class="linenos">118</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">DoPut</span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">FlightData</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">PutResult</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos">119</span>
<span class="linenos">120</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">121</span><span class="cm"> * Open a bidirectional data channel for a given descriptor. This</span>
<span class="linenos">122</span><span class="cm"> * allows clients to send and receive arbitrary Arrow data and</span>
<span class="linenos">123</span><span class="cm"> * application-specific metadata in a single logical stream. In</span>
<span class="linenos">124</span><span class="cm"> * contrast to DoGet/DoPut, this is more suited for clients</span>
<span class="linenos">125</span><span class="cm"> * offloading computation (rather than storage) to a Flight service.</span>
<span class="linenos">126</span><span class="cm"> */</span>
<span class="linenos">127</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">DoExchange</span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">FlightData</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">FlightData</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos">128</span>
<span class="linenos">129</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">130</span><span class="cm"> * Flight services can support an arbitrary number of simple actions in</span>
<span class="linenos">131</span><span class="cm"> * addition to the possible ListFlights, GetFlightInfo, DoGet, DoPut</span>
<span class="linenos">132</span><span class="cm"> * operations that are potentially available. DoAction allows a flight client</span>
<span class="linenos">133</span><span class="cm"> * to do a specific action against a flight service. An action includes</span>
<span class="linenos">134</span><span class="cm"> * opaque request and response objects that are specific to the type action</span>
<span class="linenos">135</span><span class="cm"> * being undertaken.</span>
<span class="linenos">136</span><span class="cm"> */</span>
<span class="linenos">137</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">DoAction</span><span class="p">(</span><span class="n">Action</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">Result</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos">138</span>
<span class="linenos">139</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">140</span><span class="cm"> * A flight service exposes all of the available action types that it has</span>
<span class="linenos">141</span><span class="cm"> * along with descriptions. This allows different flight consumers to</span>
<span class="linenos">142</span><span class="cm"> * understand the capabilities of the flight service.</span>
<span class="linenos">143</span><span class="cm"> */</span>
<span class="linenos">144</span><span class="w"> </span><span class="k">rpc</span><span class="w"> </span><span class="n">ListActions</span><span class="p">(</span><span class="n">Empty</span><span class="p">)</span><span class="w"> </span><span class="k">returns</span><span class="w"> </span><span class="p">(</span><span class="n">stream</span><span class="w"> </span><span class="n">ActionType</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos">145</span><span class="p">}</span>
<span class="linenos">146</span>
<span class="linenos">147</span><span class="cm">/*</span>
<span class="linenos">148</span><span class="cm"> * The request that a client provides to a server on handshake.</span>
<span class="linenos">149</span><span class="cm"> */</span>
<span class="linenos">150</span><span class="kd">message</span><span class="w"> </span><span class="nc">HandshakeRequest</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">151</span>
<span class="linenos">152</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">153</span><span class="cm"> * A defined protocol version</span>
<span class="linenos">154</span><span class="cm"> */</span>
<span class="linenos">155</span><span class="w"> </span><span class="kt">uint64</span><span class="w"> </span><span class="na">protocol_version</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">156</span>
<span class="linenos">157</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">158</span><span class="cm"> * Arbitrary auth/handshake info.</span>
<span class="linenos">159</span><span class="cm"> */</span>
<span class="linenos">160</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">payload</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">161</span><span class="p">}</span>
<span class="linenos">162</span>
<span class="linenos">163</span><span class="kd">message</span><span class="w"> </span><span class="nc">HandshakeResponse</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">164</span>
<span class="linenos">165</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">166</span><span class="cm"> * A defined protocol version</span>
<span class="linenos">167</span><span class="cm"> */</span>
<span class="linenos">168</span><span class="w"> </span><span class="kt">uint64</span><span class="w"> </span><span class="na">protocol_version</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">169</span>
<span class="linenos">170</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">171</span><span class="cm"> * Arbitrary auth/handshake info.</span>
<span class="linenos">172</span><span class="cm"> */</span>
<span class="linenos">173</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">payload</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">174</span><span class="p">}</span>
<span class="linenos">175</span>
<span class="linenos">176</span><span class="cm">/*</span>
<span class="linenos">177</span><span class="cm"> * A message for doing simple auth.</span>
<span class="linenos">178</span><span class="cm"> */</span>
<span class="linenos">179</span><span class="kd">message</span><span class="w"> </span><span class="nc">BasicAuth</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">180</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">username</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">181</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">password</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">182</span><span class="p">}</span>
<span class="linenos">183</span>
<span class="linenos">184</span><span class="kd">message</span><span class="w"> </span><span class="nc">Empty</span><span class="w"> </span><span class="p">{}</span>
<span class="linenos">185</span>
<span class="linenos">186</span><span class="cm">/*</span>
<span class="linenos">187</span><span class="cm"> * Describes an available action, including both the name used for execution</span>
<span class="linenos">188</span><span class="cm"> * along with a short description of the purpose of the action.</span>
<span class="linenos">189</span><span class="cm"> */</span>
<span class="linenos">190</span><span class="kd">message</span><span class="w"> </span><span class="nc">ActionType</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">191</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">type</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">192</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">description</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">193</span><span class="p">}</span>
<span class="linenos">194</span>
<span class="linenos">195</span><span class="cm">/*</span>
<span class="linenos">196</span><span class="cm"> * A service specific expression that can be used to return a limited set</span>
<span class="linenos">197</span><span class="cm"> * of available Arrow Flight streams.</span>
<span class="linenos">198</span><span class="cm"> */</span>
<span class="linenos">199</span><span class="kd">message</span><span class="w"> </span><span class="nc">Criteria</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">200</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">expression</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">201</span><span class="p">}</span>
<span class="linenos">202</span>
<span class="linenos">203</span><span class="cm">/*</span>
<span class="linenos">204</span><span class="cm"> * An opaque action specific for the service.</span>
<span class="linenos">205</span><span class="cm"> */</span>
<span class="linenos">206</span><span class="kd">message</span><span class="w"> </span><span class="nc">Action</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">207</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">type</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">208</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">body</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">209</span><span class="p">}</span>
<span class="linenos">210</span>
<span class="linenos">211</span><span class="cm">/*</span>
<span class="linenos">212</span><span class="cm"> * The request of the CancelFlightInfo action.</span>
<span class="linenos">213</span><span class="cm"> *</span>
<span class="linenos">214</span><span class="cm"> * The request should be stored in Action.body.</span>
<span class="linenos">215</span><span class="cm"> */</span>
<span class="linenos">216</span><span class="kd">message</span><span class="w"> </span><span class="nc">CancelFlightInfoRequest</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">217</span><span class="w"> </span><span class="n">FlightInfo</span><span class="w"> </span><span class="na">info</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">218</span><span class="p">}</span>
<span class="linenos">219</span>
<span class="linenos">220</span><span class="cm">/*</span>
<span class="linenos">221</span><span class="cm"> * The request of the RenewFlightEndpoint action.</span>
<span class="linenos">222</span><span class="cm"> *</span>
<span class="linenos">223</span><span class="cm"> * The request should be stored in Action.body.</span>
<span class="linenos">224</span><span class="cm"> */</span>
<span class="linenos">225</span><span class="kd">message</span><span class="w"> </span><span class="nc">RenewFlightEndpointRequest</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">226</span><span class="w"> </span><span class="n">FlightEndpoint</span><span class="w"> </span><span class="na">endpoint</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">227</span><span class="p">}</span>
<span class="linenos">228</span>
<span class="linenos">229</span><span class="cm">/*</span>
<span class="linenos">230</span><span class="cm"> * An opaque result returned after executing an action.</span>
<span class="linenos">231</span><span class="cm"> */</span>
<span class="linenos">232</span><span class="kd">message</span><span class="w"> </span><span class="nc">Result</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">233</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">body</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">234</span><span class="p">}</span>
<span class="linenos">235</span>
<span class="linenos">236</span><span class="cm">/*</span>
<span class="linenos">237</span><span class="cm"> * The result of a cancel operation.</span>
<span class="linenos">238</span><span class="cm"> *</span>
<span class="linenos">239</span><span class="cm"> * This is used by CancelFlightInfoResult.status.</span>
<span class="linenos">240</span><span class="cm"> */</span>
<span class="linenos">241</span><span class="kd">enum</span><span class="w"> </span><span class="n">CancelStatus</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">242</span><span class="w"> </span><span class="c1">// The cancellation status is unknown. Servers should avoid using</span>
<span class="linenos">243</span><span class="w"> </span><span class="c1">// this value (send a NOT_FOUND error if the requested query is</span>
<span class="linenos">244</span><span class="w"> </span><span class="c1">// not known). Clients can retry the request.</span>
<span class="linenos">245</span><span class="w"> </span><span class="na">CANCEL_STATUS_UNSPECIFIED</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span>
<span class="linenos">246</span><span class="w"> </span><span class="c1">// The cancellation request is complete. Subsequent requests with</span>
<span class="linenos">247</span><span class="w"> </span><span class="c1">// the same payload may return CANCELLED or a NOT_FOUND error.</span>
<span class="linenos">248</span><span class="w"> </span><span class="na">CANCEL_STATUS_CANCELLED</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">249</span><span class="w"> </span><span class="c1">// The cancellation request is in progress. The client may retry</span>
<span class="linenos">250</span><span class="w"> </span><span class="c1">// the cancellation request.</span>
<span class="linenos">251</span><span class="w"> </span><span class="na">CANCEL_STATUS_CANCELLING</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">252</span><span class="w"> </span><span class="c1">// The query is not cancellable. The client should not retry the</span>
<span class="linenos">253</span><span class="w"> </span><span class="c1">// cancellation request.</span>
<span class="linenos">254</span><span class="w"> </span><span class="na">CANCEL_STATUS_NOT_CANCELLABLE</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">255</span><span class="p">}</span>
<span class="linenos">256</span>
<span class="linenos">257</span><span class="cm">/*</span>
<span class="linenos">258</span><span class="cm"> * The result of the CancelFlightInfo action.</span>
<span class="linenos">259</span><span class="cm"> *</span>
<span class="linenos">260</span><span class="cm"> * The result should be stored in Result.body.</span>
<span class="linenos">261</span><span class="cm"> */</span>
<span class="linenos">262</span><span class="kd">message</span><span class="w"> </span><span class="nc">CancelFlightInfoResult</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">263</span><span class="w"> </span><span class="n">CancelStatus</span><span class="w"> </span><span class="na">status</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">264</span><span class="p">}</span>
<span class="linenos">265</span>
<span class="linenos">266</span><span class="cm">/*</span>
<span class="linenos">267</span><span class="cm"> * Wrap the result of a getSchema call</span>
<span class="linenos">268</span><span class="cm"> */</span>
<span class="linenos">269</span><span class="kd">message</span><span class="w"> </span><span class="nc">SchemaResult</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">270</span><span class="w"> </span><span class="c1">// The schema of the dataset in its IPC form:</span>
<span class="linenos">271</span><span class="w"> </span><span class="c1">// 4 bytes - an optional IPC_CONTINUATION_TOKEN prefix</span>
<span class="linenos">272</span><span class="w"> </span><span class="c1">// 4 bytes - the byte length of the payload</span>
<span class="linenos">273</span><span class="w"> </span><span class="c1">// a flatbuffer Message whose header is the Schema</span>
<span class="linenos">274</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">schema</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">275</span><span class="p">}</span>
<span class="linenos">276</span>
<span class="linenos">277</span><span class="cm">/*</span>
<span class="linenos">278</span><span class="cm"> * The name or tag for a Flight. May be used as a way to retrieve or generate</span>
<span class="linenos">279</span><span class="cm"> * a flight or be used to expose a set of previously defined flights.</span>
<span class="linenos">280</span><span class="cm"> */</span>
<span class="linenos">281</span><span class="kd">message</span><span class="w"> </span><span class="nc">FlightDescriptor</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">282</span>
<span class="linenos">283</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">284</span><span class="cm"> * Describes what type of descriptor is defined.</span>
<span class="linenos">285</span><span class="cm"> */</span>
<span class="linenos">286</span><span class="w"> </span><span class="kd">enum</span><span class="w"> </span><span class="n">DescriptorType</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">287</span>
<span class="linenos">288</span><span class="w"> </span><span class="c1">// Protobuf pattern, not used.</span>
<span class="linenos">289</span><span class="w"> </span><span class="na">UNKNOWN</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span>
<span class="linenos">290</span>
<span class="linenos">291</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">292</span><span class="cm"> * A named path that identifies a dataset. A path is composed of a string</span>
<span class="linenos">293</span><span class="cm"> * or list of strings describing a particular dataset. This is conceptually</span>
<span class="linenos">294</span><span class="cm"> * similar to a path inside a filesystem.</span>
<span class="linenos">295</span><span class="cm"> */</span>
<span class="linenos">296</span><span class="w"> </span><span class="na">PATH</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">297</span>
<span class="linenos">298</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">299</span><span class="cm"> * An opaque command to generate a dataset.</span>
<span class="linenos">300</span><span class="cm"> */</span>
<span class="linenos">301</span><span class="w"> </span><span class="na">CMD</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">302</span><span class="w"> </span><span class="p">}</span>
<span class="linenos">303</span>
<span class="linenos">304</span><span class="w"> </span><span class="n">DescriptorType</span><span class="w"> </span><span class="na">type</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">305</span>
<span class="linenos">306</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">307</span><span class="cm"> * Opaque value used to express a command. Should only be defined when</span>
<span class="linenos">308</span><span class="cm"> * type = CMD.</span>
<span class="linenos">309</span><span class="cm"> */</span>
<span class="linenos">310</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">cmd</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">311</span>
<span class="linenos">312</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">313</span><span class="cm"> * List of strings identifying a particular dataset. Should only be defined</span>
<span class="linenos">314</span><span class="cm"> * when type = PATH.</span>
<span class="linenos">315</span><span class="cm"> */</span>
<span class="linenos">316</span><span class="w"> </span><span class="k">repeated</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">path</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">317</span><span class="p">}</span>
<span class="linenos">318</span>
<span class="linenos">319</span><span class="cm">/*</span>
<span class="linenos">320</span><span class="cm"> * The access coordinates for retrieval of a dataset. With a FlightInfo, a</span>
<span class="linenos">321</span><span class="cm"> * consumer is able to determine how to retrieve a dataset.</span>
<span class="linenos">322</span><span class="cm"> */</span>
<span class="linenos">323</span><span class="kd">message</span><span class="w"> </span><span class="nc">FlightInfo</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">324</span><span class="w"> </span><span class="c1">// The schema of the dataset in its IPC form:</span>
<span class="linenos">325</span><span class="w"> </span><span class="c1">// 4 bytes - an optional IPC_CONTINUATION_TOKEN prefix</span>
<span class="linenos">326</span><span class="w"> </span><span class="c1">// 4 bytes - the byte length of the payload</span>
<span class="linenos">327</span><span class="w"> </span><span class="c1">// a flatbuffer Message whose header is the Schema</span>
<span class="linenos">328</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">schema</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">329</span>
<span class="linenos">330</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">331</span><span class="cm"> * The descriptor associated with this info.</span>
<span class="linenos">332</span><span class="cm"> */</span>
<span class="linenos">333</span><span class="w"> </span><span class="n">FlightDescriptor</span><span class="w"> </span><span class="na">flight_descriptor</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">334</span>
<span class="linenos">335</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">336</span><span class="cm"> * A list of endpoints associated with the flight. To consume the</span>
<span class="linenos">337</span><span class="cm"> * whole flight, all endpoints (and hence all Tickets) must be</span>
<span class="linenos">338</span><span class="cm"> * consumed. Endpoints can be consumed in any order.</span>
<span class="linenos">339</span><span class="cm"> *</span>
<span class="linenos">340</span><span class="cm"> * In other words, an application can use multiple endpoints to</span>
<span class="linenos">341</span><span class="cm"> * represent partitioned data.</span>
<span class="linenos">342</span><span class="cm"> *</span>
<span class="linenos">343</span><span class="cm"> * If the returned data has an ordering, an application can use</span>
<span class="linenos">344</span><span class="cm"> * &quot;FlightInfo.ordered = true&quot; or should return the all data in a</span>
<span class="linenos">345</span><span class="cm"> * single endpoint. Otherwise, there is no ordering defined on</span>
<span class="linenos">346</span><span class="cm"> * endpoints or the data within.</span>
<span class="linenos">347</span><span class="cm"> *</span>
<span class="linenos">348</span><span class="cm"> * A client can read ordered data by reading data from returned</span>
<span class="linenos">349</span><span class="cm"> * endpoints, in order, from front to back.</span>
<span class="linenos">350</span><span class="cm"> *</span>
<span class="linenos">351</span><span class="cm"> * Note that a client may ignore &quot;FlightInfo.ordered = true&quot;. If an</span>
<span class="linenos">352</span><span class="cm"> * ordering is important for an application, an application must</span>
<span class="linenos">353</span><span class="cm"> * choose one of them:</span>
<span class="linenos">354</span><span class="cm"> *</span>
<span class="linenos">355</span><span class="cm"> * * An application requires that all clients must read data in</span>
<span class="linenos">356</span><span class="cm"> * returned endpoints order.</span>
<span class="linenos">357</span><span class="cm"> * * An application must return the all data in a single endpoint.</span>
<span class="linenos">358</span><span class="cm"> */</span>
<span class="linenos">359</span><span class="w"> </span><span class="k">repeated</span><span class="w"> </span><span class="n">FlightEndpoint</span><span class="w"> </span><span class="na">endpoint</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">360</span>
<span class="linenos">361</span><span class="w"> </span><span class="c1">// Set these to -1 if unknown.</span>
<span class="linenos">362</span><span class="w"> </span><span class="kt">int64</span><span class="w"> </span><span class="na">total_records</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">4</span><span class="p">;</span>
<span class="linenos">363</span><span class="w"> </span><span class="kt">int64</span><span class="w"> </span><span class="na">total_bytes</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">5</span><span class="p">;</span>
<span class="linenos">364</span>
<span class="linenos">365</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">366</span><span class="cm"> * FlightEndpoints are in the same order as the data.</span>
<span class="linenos">367</span><span class="cm"> */</span>
<span class="linenos">368</span><span class="w"> </span><span class="kt">bool</span><span class="w"> </span><span class="na">ordered</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">6</span><span class="p">;</span>
<span class="linenos">369</span>
<span class="linenos">370</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">371</span><span class="cm"> * Application-defined metadata.</span>
<span class="linenos">372</span><span class="cm"> *</span>
<span class="linenos">373</span><span class="cm"> * There is no inherent or required relationship between this</span>
<span class="linenos">374</span><span class="cm"> * and the app_metadata fields in the FlightEndpoints or resulting</span>
<span class="linenos">375</span><span class="cm"> * FlightData messages. Since this metadata is application-defined,</span>
<span class="linenos">376</span><span class="cm"> * a given application could define there to be a relationship,</span>
<span class="linenos">377</span><span class="cm"> * but there is none required by the spec.</span>
<span class="linenos">378</span><span class="cm"> */</span>
<span class="linenos">379</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">app_metadata</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">7</span><span class="p">;</span>
<span class="linenos">380</span><span class="p">}</span>
<span class="linenos">381</span>
<span class="linenos">382</span><span class="cm">/*</span>
<span class="linenos">383</span><span class="cm"> * The information to process a long-running query.</span>
<span class="linenos">384</span><span class="cm"> */</span>
<span class="linenos">385</span><span class="kd">message</span><span class="w"> </span><span class="nc">PollInfo</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">386</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">387</span><span class="cm"> * The currently available results.</span>
<span class="linenos">388</span><span class="cm"> *</span>
<span class="linenos">389</span><span class="cm"> * If &quot;flight_descriptor&quot; is not specified, the query is complete</span>
<span class="linenos">390</span><span class="cm"> * and &quot;info&quot; specifies all results. Otherwise, &quot;info&quot; contains</span>
<span class="linenos">391</span><span class="cm"> * partial query results.</span>
<span class="linenos">392</span><span class="cm"> *</span>
<span class="linenos">393</span><span class="cm"> * Note that each PollInfo response contains a complete</span>
<span class="linenos">394</span><span class="cm"> * FlightInfo (not just the delta between the previous and current</span>
<span class="linenos">395</span><span class="cm"> * FlightInfo).</span>
<span class="linenos">396</span><span class="cm"> *</span>
<span class="linenos">397</span><span class="cm"> * Subsequent PollInfo responses may only append new endpoints to</span>
<span class="linenos">398</span><span class="cm"> * info.</span>
<span class="linenos">399</span><span class="cm"> *</span>
<span class="linenos">400</span><span class="cm"> * Clients can begin fetching results via DoGet(Ticket) with the</span>
<span class="linenos">401</span><span class="cm"> * ticket in the info before the query is</span>
<span class="linenos">402</span><span class="cm"> * completed. FlightInfo.ordered is also valid.</span>
<span class="linenos">403</span><span class="cm"> */</span>
<span class="linenos">404</span><span class="w"> </span><span class="n">FlightInfo</span><span class="w"> </span><span class="na">info</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">405</span>
<span class="linenos">406</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">407</span><span class="cm"> * The descriptor the client should use on the next try.</span>
<span class="linenos">408</span><span class="cm"> * If unset, the query is complete.</span>
<span class="linenos">409</span><span class="cm"> */</span>
<span class="linenos">410</span><span class="w"> </span><span class="n">FlightDescriptor</span><span class="w"> </span><span class="na">flight_descriptor</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">411</span>
<span class="linenos">412</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">413</span><span class="cm"> * Query progress. If known, must be in [0.0, 1.0] but need not be</span>
<span class="linenos">414</span><span class="cm"> * monotonic or nondecreasing. If unknown, do not set.</span>
<span class="linenos">415</span><span class="cm"> */</span>
<span class="linenos">416</span><span class="w"> </span><span class="k">optional</span><span class="w"> </span><span class="kt">double</span><span class="w"> </span><span class="na">progress</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">417</span>
<span class="linenos">418</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">419</span><span class="cm"> * Expiration time for this request. After this passes, the server</span>
<span class="linenos">420</span><span class="cm"> * might not accept the retry descriptor anymore (and the query may</span>
<span class="linenos">421</span><span class="cm"> * be cancelled). This may be updated on a call to PollFlightInfo.</span>
<span class="linenos">422</span><span class="cm"> */</span>
<span class="linenos">423</span><span class="w"> </span><span class="n">google.protobuf.Timestamp</span><span class="w"> </span><span class="na">expiration_time</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">4</span><span class="p">;</span>
<span class="linenos">424</span><span class="p">}</span>
<span class="linenos">425</span>
<span class="linenos">426</span><span class="cm">/*</span>
<span class="linenos">427</span><span class="cm"> * A particular stream or split associated with a flight.</span>
<span class="linenos">428</span><span class="cm"> */</span>
<span class="linenos">429</span><span class="kd">message</span><span class="w"> </span><span class="nc">FlightEndpoint</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">430</span>
<span class="linenos">431</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">432</span><span class="cm"> * Token used to retrieve this stream.</span>
<span class="linenos">433</span><span class="cm"> */</span>
<span class="linenos">434</span><span class="w"> </span><span class="n">Ticket</span><span class="w"> </span><span class="na">ticket</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">435</span>
<span class="linenos">436</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">437</span><span class="cm"> * A list of URIs where this ticket can be redeemed via DoGet().</span>
<span class="linenos">438</span><span class="cm"> *</span>
<span class="linenos">439</span><span class="cm"> * If the list is empty, the expectation is that the ticket can only</span>
<span class="linenos">440</span><span class="cm"> * be redeemed on the current service where the ticket was</span>
<span class="linenos">441</span><span class="cm"> * generated.</span>
<span class="linenos">442</span><span class="cm"> *</span>
<span class="linenos">443</span><span class="cm"> * If the list is not empty, the expectation is that the ticket can be</span>
<span class="linenos">444</span><span class="cm"> * redeemed at any of the locations, and that the data returned will be</span>
<span class="linenos">445</span><span class="cm"> * equivalent. In this case, the ticket may only be redeemed at one of the</span>
<span class="linenos">446</span><span class="cm"> * given locations, and not (necessarily) on the current service. If one</span>
<span class="linenos">447</span><span class="cm"> * of the given locations is &quot;arrow-flight-reuse-connection://?&quot;, the</span>
<span class="linenos">448</span><span class="cm"> * client may redeem the ticket on the service where the ticket was</span>
<span class="linenos">449</span><span class="cm"> * generated (i.e., the same as above), in addition to the other</span>
<span class="linenos">450</span><span class="cm"> * locations. (This URI was chosen to maximize compatibility, as &#39;scheme:&#39;</span>
<span class="linenos">451</span><span class="cm"> * or &#39;scheme://&#39; are not accepted by Java&#39;s java.net.URI.)</span>
<span class="linenos">452</span><span class="cm"> *</span>
<span class="linenos">453</span><span class="cm"> * In other words, an application can use multiple locations to</span>
<span class="linenos">454</span><span class="cm"> * represent redundant and/or load balanced services.</span>
<span class="linenos">455</span><span class="cm"> */</span>
<span class="linenos">456</span><span class="w"> </span><span class="k">repeated</span><span class="w"> </span><span class="n">Location</span><span class="w"> </span><span class="na">location</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">457</span>
<span class="linenos">458</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">459</span><span class="cm"> * Expiration time of this stream. If present, clients may assume</span>
<span class="linenos">460</span><span class="cm"> * they can retry DoGet requests. Otherwise, it is</span>
<span class="linenos">461</span><span class="cm"> * application-defined whether DoGet requests may be retried.</span>
<span class="linenos">462</span><span class="cm"> */</span>
<span class="linenos">463</span><span class="w"> </span><span class="n">google.protobuf.Timestamp</span><span class="w"> </span><span class="na">expiration_time</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">464</span>
<span class="linenos">465</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">466</span><span class="cm"> * Application-defined metadata.</span>
<span class="linenos">467</span><span class="cm"> *</span>
<span class="linenos">468</span><span class="cm"> * There is no inherent or required relationship between this</span>
<span class="linenos">469</span><span class="cm"> * and the app_metadata fields in the FlightInfo or resulting</span>
<span class="linenos">470</span><span class="cm"> * FlightData messages. Since this metadata is application-defined,</span>
<span class="linenos">471</span><span class="cm"> * a given application could define there to be a relationship,</span>
<span class="linenos">472</span><span class="cm"> * but there is none required by the spec.</span>
<span class="linenos">473</span><span class="cm"> */</span>
<span class="linenos">474</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">app_metadata</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">4</span><span class="p">;</span>
<span class="linenos">475</span><span class="p">}</span>
<span class="linenos">476</span>
<span class="linenos">477</span><span class="cm">/*</span>
<span class="linenos">478</span><span class="cm"> * A location where a Flight service will accept retrieval of a particular</span>
<span class="linenos">479</span><span class="cm"> * stream given a ticket.</span>
<span class="linenos">480</span><span class="cm"> */</span>
<span class="linenos">481</span><span class="kd">message</span><span class="w"> </span><span class="nc">Location</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">482</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">uri</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">483</span><span class="p">}</span>
<span class="linenos">484</span>
<span class="linenos">485</span><span class="cm">/*</span>
<span class="linenos">486</span><span class="cm"> * An opaque identifier that the service can use to retrieve a particular</span>
<span class="linenos">487</span><span class="cm"> * portion of a stream.</span>
<span class="linenos">488</span><span class="cm"> *</span>
<span class="linenos">489</span><span class="cm"> * Tickets are meant to be single use. It is an error/application-defined</span>
<span class="linenos">490</span><span class="cm"> * behavior to reuse a ticket.</span>
<span class="linenos">491</span><span class="cm"> */</span>
<span class="linenos">492</span><span class="kd">message</span><span class="w"> </span><span class="nc">Ticket</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">493</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">ticket</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">494</span><span class="p">}</span>
<span class="linenos">495</span>
<span class="linenos">496</span><span class="cm">/*</span>
<span class="linenos">497</span><span class="cm"> * A batch of Arrow data as part of a stream of batches.</span>
<span class="linenos">498</span><span class="cm"> */</span>
<span class="linenos">499</span><span class="kd">message</span><span class="w"> </span><span class="nc">FlightData</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">500</span>
<span class="linenos">501</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">502</span><span class="cm"> * The descriptor of the data. This is only relevant when a client is</span>
<span class="linenos">503</span><span class="cm"> * starting a new DoPut stream.</span>
<span class="linenos">504</span><span class="cm"> */</span>
<span class="linenos">505</span><span class="w"> </span><span class="n">FlightDescriptor</span><span class="w"> </span><span class="na">flight_descriptor</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">506</span>
<span class="linenos">507</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">508</span><span class="cm"> * Header for message data as described in Message.fbs::Message.</span>
<span class="linenos">509</span><span class="cm"> */</span>
<span class="linenos">510</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">data_header</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">511</span>
<span class="linenos">512</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">513</span><span class="cm"> * Application-defined metadata.</span>
<span class="linenos">514</span><span class="cm"> */</span>
<span class="linenos">515</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">app_metadata</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">516</span>
<span class="linenos">517</span><span class="w"> </span><span class="cm">/*</span>
<span class="linenos">518</span><span class="cm"> * The actual batch of Arrow data. Preferably handled with minimal-copies</span>
<span class="linenos">519</span><span class="cm"> * coming last in the definition to help with sidecar patterns (it is</span>
<span class="linenos">520</span><span class="cm"> * expected that some implementations will fetch this field off the wire</span>
<span class="linenos">521</span><span class="cm"> * with specialized code to avoid extra memory copies).</span>
<span class="linenos">522</span><span class="cm"> */</span>
<span class="linenos">523</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">data_body</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1000</span><span class="p">;</span>
<span class="linenos">524</span><span class="p">}</span>
<span class="linenos">525</span>
<span class="linenos">526</span><span class="cm">/**</span>
<span class="linenos">527</span><span class="cm"> * The response message associated with the submission of a DoPut.</span>
<span class="linenos">528</span><span class="cm"> */</span>
<span class="linenos">529</span><span class="kd">message</span><span class="w"> </span><span class="nc">PutResult</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">530</span><span class="w"> </span><span class="kt">bytes</span><span class="w"> </span><span class="na">app_metadata</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">531</span><span class="p">}</span>
<span class="linenos">532</span>
<span class="linenos">533</span><span class="cm">/*</span>
<span class="linenos">534</span><span class="cm"> * EXPERIMENTAL: Union of possible value types for a Session Option to be set to.</span>
<span class="linenos">535</span><span class="cm"> *</span>
<span class="linenos">536</span><span class="cm"> * By convention, an attempt to set a valueless SessionOptionValue should</span>
<span class="linenos">537</span><span class="cm"> * attempt to unset or clear the named option value on the server.</span>
<span class="linenos">538</span><span class="cm"> */</span>
<span class="linenos">539</span><span class="kd">message</span><span class="w"> </span><span class="nc">SessionOptionValue</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">540</span><span class="w"> </span><span class="kd">message</span><span class="w"> </span><span class="nc">StringListValue</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">541</span><span class="w"> </span><span class="k">repeated</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">values</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">542</span><span class="w"> </span><span class="p">}</span>
<span class="linenos">543</span>
<span class="linenos">544</span><span class="w"> </span><span class="k">oneof</span><span class="w"> </span><span class="n">option_value</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">545</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="na">string_value</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">546</span><span class="w"> </span><span class="kt">bool</span><span class="w"> </span><span class="na">bool_value</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">547</span><span class="w"> </span><span class="kt">sfixed64</span><span class="w"> </span><span class="na">int64_value</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">548</span><span class="w"> </span><span class="kt">double</span><span class="w"> </span><span class="na">double_value</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">4</span><span class="p">;</span>
<span class="linenos">549</span><span class="w"> </span><span class="n">StringListValue</span><span class="w"> </span><span class="na">string_list_value</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">5</span><span class="p">;</span>
<span class="linenos">550</span><span class="w"> </span><span class="p">}</span>
<span class="linenos">551</span><span class="p">}</span>
<span class="linenos">552</span>
<span class="linenos">553</span><span class="cm">/*</span>
<span class="linenos">554</span><span class="cm"> * EXPERIMENTAL: A request to set session options for an existing or new (implicit)</span>
<span class="linenos">555</span><span class="cm"> * server session.</span>
<span class="linenos">556</span><span class="cm"> *</span>
<span class="linenos">557</span><span class="cm"> * Sessions are persisted and referenced via a transport-level state management, typically</span>
<span class="linenos">558</span><span class="cm"> * RFC 6265 HTTP cookies when using an HTTP transport. The suggested cookie name or state</span>
<span class="linenos">559</span><span class="cm"> * context key is &#39;arrow_flight_session_id&#39;, although implementations may freely choose their</span>
<span class="linenos">560</span><span class="cm"> * own name.</span>
<span class="linenos">561</span><span class="cm"> *</span>
<span class="linenos">562</span><span class="cm"> * Session creation (if one does not already exist) is implied by this RPC request, however</span>
<span class="linenos">563</span><span class="cm"> * server implementations may choose to initiate a session that also contains client-provided</span>
<span class="linenos">564</span><span class="cm"> * session options at any other time, e.g. on authentication, or when any other call is made</span>
<span class="linenos">565</span><span class="cm"> * and the server wishes to use a session to persist any state (or lack thereof).</span>
<span class="linenos">566</span><span class="cm"> */</span>
<span class="linenos">567</span><span class="kd">message</span><span class="w"> </span><span class="nc">SetSessionOptionsRequest</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">568</span><span class="w"> </span><span class="n">map</span><span class="p">&lt;</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="n">SessionOptionValue</span><span class="p">&gt;</span><span class="w"> </span><span class="na">session_options</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">569</span><span class="p">}</span>
<span class="linenos">570</span>
<span class="linenos">571</span><span class="cm">/*</span>
<span class="linenos">572</span><span class="cm"> * EXPERIMENTAL: The results (individually) of setting a set of session options.</span>
<span class="linenos">573</span><span class="cm"> *</span>
<span class="linenos">574</span><span class="cm"> * Option names should only be present in the response if they were not successfully</span>
<span class="linenos">575</span><span class="cm"> * set on the server; that is, a response without an Error for a name provided in the</span>
<span class="linenos">576</span><span class="cm"> * SetSessionOptionsRequest implies that the named option value was set successfully.</span>
<span class="linenos">577</span><span class="cm"> */</span>
<span class="linenos">578</span><span class="kd">message</span><span class="w"> </span><span class="nc">SetSessionOptionsResult</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">579</span><span class="w"> </span><span class="kd">enum</span><span class="w"> </span><span class="n">ErrorValue</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">580</span><span class="w"> </span><span class="c1">// Protobuf deserialization fallback value: The status is unknown or unrecognized.</span>
<span class="linenos">581</span><span class="w"> </span><span class="c1">// Servers should avoid using this value. The request may be retried by the client.</span>
<span class="linenos">582</span><span class="w"> </span><span class="na">UNSPECIFIED</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span>
<span class="linenos">583</span><span class="w"> </span><span class="c1">// The given session option name is invalid.</span>
<span class="linenos">584</span><span class="w"> </span><span class="na">INVALID_NAME</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">585</span><span class="w"> </span><span class="c1">// The session option value or type is invalid.</span>
<span class="linenos">586</span><span class="w"> </span><span class="na">INVALID_VALUE</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">587</span><span class="w"> </span><span class="c1">// The session option cannot be set.</span>
<span class="linenos">588</span><span class="w"> </span><span class="na">ERROR</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">589</span><span class="w"> </span><span class="p">}</span>
<span class="linenos">590</span>
<span class="linenos">591</span><span class="w"> </span><span class="kd">message</span><span class="w"> </span><span class="nc">Error</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">592</span><span class="w"> </span><span class="n">ErrorValue</span><span class="w"> </span><span class="na">value</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">593</span><span class="w"> </span><span class="p">}</span>
<span class="linenos">594</span>
<span class="linenos">595</span><span class="w"> </span><span class="n">map</span><span class="p">&lt;</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="n">Error</span><span class="p">&gt;</span><span class="w"> </span><span class="na">errors</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">596</span><span class="p">}</span>
<span class="linenos">597</span>
<span class="linenos">598</span><span class="cm">/*</span>
<span class="linenos">599</span><span class="cm"> * EXPERIMENTAL: A request to access the session options for the current server session.</span>
<span class="linenos">600</span><span class="cm"> *</span>
<span class="linenos">601</span><span class="cm"> * The existing session is referenced via a cookie header or similar (see</span>
<span class="linenos">602</span><span class="cm"> * SetSessionOptionsRequest above); it is an error to make this request with a missing,</span>
<span class="linenos">603</span><span class="cm"> * invalid, or expired session cookie header or other implementation-defined session</span>
<span class="linenos">604</span><span class="cm"> * reference token.</span>
<span class="linenos">605</span><span class="cm"> */</span>
<span class="linenos">606</span><span class="kd">message</span><span class="w"> </span><span class="nc">GetSessionOptionsRequest</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">607</span><span class="p">}</span>
<span class="linenos">608</span>
<span class="linenos">609</span><span class="cm">/*</span>
<span class="linenos">610</span><span class="cm"> * EXPERIMENTAL: The result containing the current server session options.</span>
<span class="linenos">611</span><span class="cm"> */</span>
<span class="linenos">612</span><span class="kd">message</span><span class="w"> </span><span class="nc">GetSessionOptionsResult</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">613</span><span class="w"> </span><span class="n">map</span><span class="p">&lt;</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="n">SessionOptionValue</span><span class="p">&gt;</span><span class="w"> </span><span class="na">session_options</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">614</span><span class="p">}</span>
<span class="linenos">615</span>
<span class="linenos">616</span><span class="cm">/*</span>
<span class="linenos">617</span><span class="cm"> * Request message for the &quot;Close Session&quot; action.</span>
<span class="linenos">618</span><span class="cm"> *</span>
<span class="linenos">619</span><span class="cm"> * The exiting session is referenced via a cookie header.</span>
<span class="linenos">620</span><span class="cm"> */</span>
<span class="linenos">621</span><span class="kd">message</span><span class="w"> </span><span class="nc">CloseSessionRequest</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">622</span><span class="p">}</span>
<span class="linenos">623</span>
<span class="linenos">624</span><span class="cm">/*</span>
<span class="linenos">625</span><span class="cm"> * The result of closing a session.</span>
<span class="linenos">626</span><span class="cm"> */</span>
<span class="linenos">627</span><span class="kd">message</span><span class="w"> </span><span class="nc">CloseSessionResult</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">628</span><span class="w"> </span><span class="kd">enum</span><span class="w"> </span><span class="n">Status</span><span class="w"> </span><span class="p">{</span>
<span class="linenos">629</span><span class="w"> </span><span class="c1">// Protobuf deserialization fallback value: The session close status is unknown or</span>
<span class="linenos">630</span><span class="w"> </span><span class="c1">// not recognized. Servers should avoid using this value (send a NOT_FOUND error if</span>
<span class="linenos">631</span><span class="w"> </span><span class="c1">// the requested session is not known or expired). Clients can retry the request.</span>
<span class="linenos">632</span><span class="w"> </span><span class="na">UNSPECIFIED</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span>
<span class="linenos">633</span><span class="w"> </span><span class="c1">// The session close request is complete. Subsequent requests with</span>
<span class="linenos">634</span><span class="w"> </span><span class="c1">// the same session produce a NOT_FOUND error.</span>
<span class="linenos">635</span><span class="w"> </span><span class="na">CLOSED</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">636</span><span class="w"> </span><span class="c1">// The session close request is in progress. The client may retry</span>
<span class="linenos">637</span><span class="w"> </span><span class="c1">// the close request.</span>
<span class="linenos">638</span><span class="w"> </span><span class="na">CLOSING</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="p">;</span>
<span class="linenos">639</span><span class="w"> </span><span class="c1">// The session is not closeable. The client should not retry the</span>
<span class="linenos">640</span><span class="w"> </span><span class="c1">// close request.</span>
<span class="linenos">641</span><span class="w"> </span><span class="na">NOT_CLOSEABLE</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">3</span><span class="p">;</span>
<span class="linenos">642</span><span class="w"> </span><span class="p">}</span>
<span class="linenos">643</span>
<span class="linenos">644</span><span class="w"> </span><span class="n">Status</span><span class="w"> </span><span class="na">status</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="linenos">645</span><span class="p">}</span>
</pre></div>
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