// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.
//
// Protobuf used for introspection of RPC services (eg listing in-flight RPCs,
// reflection, etc)
syntax = "proto2";

package kudu.rpc;

option java_package = "org.apache.kudu";

import "kudu/rpc/rpc_header.proto";

message RpcCallInProgressPB {
  required RequestHeader header = 1;
  optional string trace_buffer = 2;
  optional uint64 micros_elapsed = 3;

  enum State {
    UNKNOWN = 999;

    // States for OutboundCall
    ON_OUTBOUND_QUEUE = 1;
    SENDING = 2;
    SENT = 3;
    TIMED_OUT = 4;
    FINISHED_ERROR = 5;
    FINISHED_SUCCESS = 6;
    NEGOTIATION_TIMED_OUT = 7;
    FINISHED_NEGOTIATION_ERROR = 8;
    CANCELLED = 9;

    // TODO(todd): add states for InboundCall
  }

  optional State state = 4;
}

// The SocketStatsPB message is used to report on socket-level information
// for RPC-related TCP connections (Linux-only). Essentially, the message
// contains some metrics and counters from Linux-specific 'tcp_info' structure
// defined in /usr/include/linux/tcp.h. For more information on the TCP on
// Linux, see http://man7.org/linux/man-pages/man7/tcp.7.html
message SocketStatsPB {
  optional uint32 rtt = 1;
  optional uint32 rttvar = 2;
  optional uint32 snd_cwnd = 3;
  optional uint32 total_retrans = 4;

  optional uint32 pacing_rate = 5;
  optional uint32 max_pacing_rate = 6;

  optional uint64 bytes_acked = 7;
  optional uint64 bytes_received = 8;
  optional uint32 segs_out = 9;
  optional uint32 segs_in = 10;

  optional uint64 send_queue_bytes = 11;
  optional uint64 receive_queue_bytes = 12;

  // Calculated sender throughput.
  optional int32 send_bytes_per_sec = 13;
};

// Debugging information about a currently-open RPC connection.
message RpcConnectionPB {
  enum StateType {
    UNKNOWN = 999;
    NEGOTIATING = 0;  // Connection is still being negotiated.
    OPEN = 1;         // Connection is active.
  };

  required string remote_ip = 1;
  required StateType state = 2;
  // TODO: swap out for separate fields
  optional string remote_user_credentials = 3;
  repeated RpcCallInProgressPB calls_in_flight = 4;
  optional int64 outbound_queue_size = 5;

  // Information on the actual TCP connection as reported by the kernel.
  optional SocketStatsPB socket_stats = 6;
}

message DumpConnectionsRequestPB {
  optional bool include_traces = 1 [ default = false ];
}

message DumpConnectionsResponsePB {
  repeated RpcConnectionPB inbound_connections = 1;
  repeated RpcConnectionPB outbound_connections = 2;
}

//------------------------------------------------------------

// A particular TraceMetric key/value pair from a sampled RPC.
message TraceMetricPB {
  // A '.'-separated path through the parent-child trace hierarchy.
  optional string child_path = 1;
  optional string key = 2;
  optional int64 value = 3;
}

// A single sampled RPC call.
message RpczSamplePB {
  // The original request header.
  optional RequestHeader header = 1;
  // The stringified request trace.
  optional string trace = 2;
  // The number of millis that this call took to complete.
  optional int32 duration_ms = 3;
  // The metrics from the sampled trace.
  repeated TraceMetricPB metrics = 4;
}

// A set of samples for a particular RPC method.
message RpczMethodPB {
  required string method_name = 1;
  repeated RpczSamplePB samples = 2;
}

// Request and response for dumping previously sampled RPC calls.
message DumpRpczStoreRequestPB {
}
message DumpRpczStoreResponsePB {
  repeated RpczMethodPB methods = 1;
}