// 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.
package kudu.tserver;

option java_package = "org.kududb.tserver";

import "kudu/common/common.proto";
import "kudu/common/wire_protocol.proto";
import "kudu/tablet/tablet.proto";

// Tablet-server specific errors use this protobuf.
message TabletServerErrorPB {
  enum Code {
    // An error which has no more specific error code.
    // The code and message in 'status' may reveal more details.
    //
    // RPCs should avoid returning this, since callers will not be
    // able to easily parse the error.
    UNKNOWN_ERROR = 1;

    // The schema provided for a request was not well-formed.
    INVALID_SCHEMA = 2;

    // The row data provided for a request was not well-formed.
    INVALID_ROW_BLOCK = 3;

    // The mutations or mutation keys provided for a request were
    // not well formed.
    INVALID_MUTATION = 4;

    // The schema provided for a request didn't match the actual
    // schema of the tablet.
    MISMATCHED_SCHEMA = 5;

    // The requested tablet_id is not currently hosted on this server.
    TABLET_NOT_FOUND = 6;

    // A request was made against a scanner ID that was either never
    // created or has expired.
    SCANNER_EXPIRED = 7;

    // An invalid scan was specified -- e.g the values passed for
    // predicates were incorrect sizes.
    INVALID_SCAN_SPEC = 8;

    // The provided configuration was not well-formed and/or
    // had a sequence number that was below the current config.
    INVALID_CONFIG = 9;

    // On a create tablet request, signals that the tablet already exists.
    TABLET_ALREADY_EXISTS = 10;

    // If the tablet has a newer schema than the requested one the "alter"
    // request will be rejected with this error.
    TABLET_HAS_A_NEWER_SCHEMA = 11;

    // The tablet is hosted on this server, but not in RUNNING state.
    TABLET_NOT_RUNNING = 12;

    // Client requested a snapshot read but the snapshot was invalid.
    INVALID_SNAPSHOT = 13;

    // An invalid scan call sequence ID was specified.
    INVALID_SCAN_CALL_SEQ_ID = 14;

    // This tserver is not the leader of the consensus configuration.
    NOT_THE_LEADER = 15;

    // The destination UUID in the request does not match this server.
    WRONG_SERVER_UUID = 16;

    // The compare-and-swap specified by an atomic RPC operation failed.
    CAS_FAILED = 17;

    // The requested operation is already inprogress, e.g. RemoteBootstrap.
    ALREADY_INPROGRESS = 18;

    // The request is throttled.
    THROTTLED = 19;
  }

  // The error code.
  required Code code = 1 [ default = UNKNOWN_ERROR ];

  // The Status object for the error. This will include a textual
  // message that may be more useful to present in log messages, etc,
  // though its error code is less specific.
  required AppStatusPB status = 2;
}


message PingRequestPB {
}

message PingResponsePB {
}

// A batched set of insert/mutate requests.
message WriteRequestPB {
  required bytes tablet_id = 1;

  // The schema as seen by the client. This may be out-of-date, in which case
  // it will be projected to the current schema automatically, with defaults/NULLs
  // being filled in.
  optional SchemaPB schema = 2;

  // Operations to perform (insert/update/delete)
  optional RowOperationsPB row_operations = 3;

  // The required consistency mode for this write.
  optional ExternalConsistencyMode external_consistency_mode = 4 [default = CLIENT_PROPAGATED];

  // A timestamp obtained by the client from a previous request.
  // TODO crypto sign this and propagate the signature along with
  // the timestamp.
  optional fixed64 propagated_timestamp = 5;
}

message WriteResponsePB {
  // If the entire WriteResponsePB request failed, the error status that
  // caused the failure. This type of error is triggered for
  // cases such as the tablet not being on this server, or the
  // schema not matching. If any error specific to a given row
  // occurs, this error will be recorded in per_row_errors below,
  // even if all rows failed.
  optional TabletServerErrorPB error = 1;

  // If errors occurred with particular row operations, then the errors
  // for those operations will be passed back in 'per_row_errors'.
  message PerRowErrorPB {
    // The index of the row in the incoming batch.
    required int32 row_index = 1;
    // The error that occurred.
    required AppStatusPB error = 2;
  }
  repeated PerRowErrorPB per_row_errors = 2;

  // The timestamp chosen by the server for this write.
  // TODO KUDU-611 propagate timestamps with server signature.
  optional fixed64 timestamp = 3;
}

// A list tablets request
message ListTabletsRequestPB {
}

// A list tablets response
message ListTabletsResponsePB {
  optional TabletServerErrorPB error = 1;

  message StatusAndSchemaPB {
    required tablet.TabletStatusPB tablet_status = 1;
    required SchemaPB schema = 2;
    optional PartitionSchemaPB partition_schema = 3;
  }

  repeated StatusAndSchemaPB status_and_schema = 2;
}

// DEPRECATED: Use ColumnPredicatePB
//
// A range predicate on one of the columns in the underlying
// data.
message ColumnRangePredicatePB {
  required ColumnSchemaPB column = 1;

  // These bounds should be encoded as follows:
  // - STRING values: simply the exact string value for the bound.
  // - other type: the canonical x86 in-memory representation -- eg for
  //   uint32s, a little-endian value.
  //
  // Note that this predicate type should not be used for NULL data --
  // NULL is defined to neither be greater than or less than other values
  // for the comparison operator. We will eventually add a special
  // predicate type for null-ness.
  //
  // Both bounds are inclusive.
  optional bytes lower_bound = 2;
  optional bytes inclusive_upper_bound = 3;
}

// List of predicates used by the Java client. Will rapidly evolve into something more reusable
// as a way to pass scanner configurations.
message ColumnRangePredicateListPB {
  repeated ColumnRangePredicatePB range_predicates = 1;
}

message NewScanRequestPB {
  // The tablet to scan.
  required bytes tablet_id = 1;

  // The maximum number of rows to scan.
  // The scanner will automatically stop yielding results and close
  // itself after reaching this number of result rows.
  optional uint64 limit = 2;

  // DEPRECATED: use column_predicates field.
  //
  // Any column range predicates to enforce.
  repeated ColumnRangePredicatePB DEPRECATED_range_predicates = 3;

  // Column predicates to enforce.
  repeated ColumnPredicatePB column_predicates = 13;

  // Encoded primary key to begin scanning at (inclusive).
  optional bytes start_primary_key = 8;
  // Encoded primary key to stop scanning at (exclusive).
  optional bytes stop_primary_key = 9;

  // Which columns to select.
  // if this is an empty list, no data will be returned, but the num_rows
  // field of the returned RowBlock will indicate how many rows passed
  // the predicates. Note that in some cases, the scan may still require
  // multiple round-trips, and the caller must aggregate the counts.
  repeated ColumnSchemaPB projected_columns = 4;

  // The read mode for this scan request.
  // See common.proto for further information about read modes.
  optional ReadMode read_mode = 5 [default = READ_LATEST];

  // The requested snapshot timestamp. This is only used
  // when the read mode is set to READ_AT_SNAPSHOT.
  optional fixed64 snap_timestamp = 6;

  // Sent by clients which previously executed CLIENT_PROPAGATED writes.
  // This updates the server's time so that no transaction will be assigned
  // a timestamp lower than or equal to 'previous_known_timestamp'
  optional fixed64 propagated_timestamp = 7;

  // Whether data blocks will be cached when read from the files or discarded after use.
  // Disable this to lower cache churn when doing large scans.
  optional bool cache_blocks = 10 [default = true];

  // Whether to order the returned rows by primary key.
  // This is used for scanner fault-tolerance.
  optional OrderMode order_mode = 11 [default = UNORDERED];

  // If retrying a scan, the final primary key retrieved in the previous scan
  // attempt. If set, this will take precedence over the `start_primary_key`
  // field, and functions as an exclusive start primary key.
  optional bytes last_primary_key = 12;
}

// A scan request. Initially, it should specify a scan. Later on, you
// can use the scanner id returned to fetch result batches with a different
// scan request.
//
// The scanner will remain open if there are more results, and it's not
// asked to be closed explicitly. Some errors on the Tablet Server may
// close the scanner automatically if the scanner state becomes
// inconsistent.
//
// Clients may choose to retry scan requests that fail to complete (due to, for
// example, a timeout or network error). If a scan request completes with an
// error result, the scanner should be closed by the client.
//
// You can fetch the results and ask the scanner to be closed to save
// a trip if you are not interested in remaining results.
//
// This is modeled somewhat after HBase's scanner API.
message ScanRequestPB {
  // If continuing an existing scan, then you must set scanner_id.
  // Otherwise, you must set 'new_scan_request'.
  optional bytes scanner_id = 1;
  optional NewScanRequestPB new_scan_request = 2;

  // The sequence ID of this call. The sequence ID should start at 0
  // with the request for a new scanner, and after each successful request,
  // the client should increment it by 1. When retrying a request, the client
  // should _not_ increment this value. If the server detects that the client
  // missed a chunk of rows from the middle of a scan, it will respond with an
  // error.
  optional uint32 call_seq_id = 3;

  // The maximum number of bytes to send in the response.
  // This is a hint, not a requirement: the server may send
  // arbitrarily fewer or more bytes than requested.
  optional uint32 batch_size_bytes = 4;

  // If set, the server will close the scanner after responding to
  // this request, regardless of whether all rows have been delivered.
  // In order to simply close a scanner without selecting any rows, you
  // may set batch_size_bytes to 0 in conjunction with setting this flag.
  optional bool close_scanner = 5;
}

message ScanResponsePB {
  // The error, if an error occurred with this request.
  optional TabletServerErrorPB error = 1;

  // When a scanner is created, returns the scanner ID which may be used
  // to pull new rows from the scanner.
  optional bytes scanner_id = 2;

  // Set to true to indicate that there may be further results to be fetched
  // from this scanner. If the scanner has no more results, then the scanner
  // ID will become invalid and cannot continue to be used.
  //
  // Note that if a scan returns no results, then the initial response from
  // the first RPC may return false in this flag, in which case there will
  // be no scanner ID assigned.
  optional bool has_more_results = 3;

  // The block of returned rows.
  //
  // NOTE: the schema-related fields will not be present in this row block.
  // The schema will match the schema requested by the client when it created
  // the scanner.
  optional RowwiseRowBlockPB data = 4;

  // The snapshot timestamp at which the scan was executed. This is only set
  // in the first response (i.e. the response to the request that had
  // 'new_scan_request' set) and only for READ_AT_SNAPSHOT scans.
  optional fixed64 snap_timestamp = 6;

  // If this is a fault-tolerant scanner, this is set to the encoded primary
  // key of the last row returned in the response.
  optional bytes last_primary_key = 7;
}

// A scanner keep-alive request.
// Updates the scanner access time, increasing its time-to-live.
message ScannerKeepAliveRequestPB {
  required bytes scanner_id = 1;
}

message ScannerKeepAliveResponsePB {
  // The error, if an error occurred with this request.
  optional TabletServerErrorPB error = 1;
}

enum TabletServerFeatures {
  UNKNOWN_FEATURE = 0;
  COLUMN_PREDICATES = 1;
}