// Copyright 2023 Google LLC
//
// Licensed 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.

syntax = "proto3";

package google.bigtable.v2;

import "google/api/annotations.proto";
import "google/api/client.proto";
import "google/api/field_behavior.proto";
import "google/api/resource.proto";
import "google/api/routing.proto";
import "google/bigtable/v2/data.proto";
import "google/bigtable/v2/request_stats.proto";
import "google/protobuf/duration.proto";
import "google/protobuf/timestamp.proto";
import "google/protobuf/wrappers.proto";
import "google/rpc/status.proto";

option csharp_namespace = "Google.Cloud.Bigtable.V2";
option go_package = "google.golang.org/genproto/googleapis/bigtable/v2;bigtable";
option java_multiple_files = true;
option java_outer_classname = "BigtableProto";
option java_package = "com.google.bigtable.v2";
option php_namespace = "Google\\Cloud\\Bigtable\\V2";
option ruby_package = "Google::Cloud::Bigtable::V2";
option (google.api.resource_definition) = {
  type: "bigtableadmin.googleapis.com/Instance"
  pattern: "projects/{project}/instances/{instance}"
};
option (google.api.resource_definition) = {
  type: "bigtableadmin.googleapis.com/Table"
  pattern: "projects/{project}/instances/{instance}/tables/{table}"
};

// Service for reading from and writing to existing Bigtable tables.
service Bigtable {
  option (google.api.default_host) = "bigtable.googleapis.com";
  option (google.api.oauth_scopes) =
      "https://www.googleapis.com/auth/bigtable.data,"
      "https://www.googleapis.com/auth/bigtable.data.readonly,"
      "https://www.googleapis.com/auth/cloud-bigtable.data,"
      "https://www.googleapis.com/auth/cloud-bigtable.data.readonly,"
      "https://www.googleapis.com/auth/cloud-platform,"
      "https://www.googleapis.com/auth/cloud-platform.read-only";

  // Streams back the contents of all requested rows in key order, optionally
  // applying the same Reader filter to each. Depending on their size,
  // rows and cells may be broken up across multiple responses, but
  // atomicity of each row will still be preserved. See the
  // ReadRowsResponse documentation for details.
  rpc ReadRows(ReadRowsRequest) returns (stream ReadRowsResponse) {
    option (google.api.http) = {
      post: "/v2/{table_name=projects/*/instances/*/tables/*}:readRows"
      body: "*"
    };
    option (google.api.routing) = {
      routing_parameters {
        field: "table_name"
        path_template: "{table_name=projects/*/instances/*/tables/*}"
      }
      routing_parameters { field: "app_profile_id" }
    };
    option (google.api.method_signature) = "table_name";
    option (google.api.method_signature) = "table_name,app_profile_id";
  }

  // Returns a sample of row keys in the table. The returned row keys will
  // delimit contiguous sections of the table of approximately equal size,
  // which can be used to break up the data for distributed tasks like
  // mapreduces.
  rpc SampleRowKeys(SampleRowKeysRequest)
      returns (stream SampleRowKeysResponse) {
    option (google.api.http) = {
      get: "/v2/{table_name=projects/*/instances/*/tables/*}:sampleRowKeys"
    };
    option (google.api.routing) = {
      routing_parameters {
        field: "table_name"
        path_template: "{table_name=projects/*/instances/*/tables/*}"
      }
      routing_parameters { field: "app_profile_id" }
    };
    option (google.api.method_signature) = "table_name";
    option (google.api.method_signature) = "table_name,app_profile_id";
  }

  // Mutates a row atomically. Cells already present in the row are left
  // unchanged unless explicitly changed by `mutation`.
  rpc MutateRow(MutateRowRequest) returns (MutateRowResponse) {
    option (google.api.http) = {
      post: "/v2/{table_name=projects/*/instances/*/tables/*}:mutateRow"
      body: "*"
    };
    option (google.api.routing) = {
      routing_parameters {
        field: "table_name"
        path_template: "{table_name=projects/*/instances/*/tables/*}"
      }
      routing_parameters { field: "app_profile_id" }
    };
    option (google.api.method_signature) = "table_name,row_key,mutations";
    option (google.api.method_signature) =
        "table_name,row_key,mutations,app_profile_id";
  }

  // Mutates multiple rows in a batch. Each individual row is mutated
  // atomically as in MutateRow, but the entire batch is not executed
  // atomically.
  rpc MutateRows(MutateRowsRequest) returns (stream MutateRowsResponse) {
    option (google.api.http) = {
      post: "/v2/{table_name=projects/*/instances/*/tables/*}:mutateRows"
      body: "*"
    };
    option (google.api.routing) = {
      routing_parameters {
        field: "table_name"
        path_template: "{table_name=projects/*/instances/*/tables/*}"
      }
      routing_parameters { field: "app_profile_id" }
    };
    option (google.api.method_signature) = "table_name,entries";
    option (google.api.method_signature) = "table_name,entries,app_profile_id";
  }

  // Mutates a row atomically based on the output of a predicate Reader filter.
  rpc CheckAndMutateRow(CheckAndMutateRowRequest)
      returns (CheckAndMutateRowResponse) {
    option (google.api.http) = {
      post: "/v2/{table_name=projects/*/instances/*/tables/*}:checkAndMutateRow"
      body: "*"
    };
    option (google.api.routing) = {
      routing_parameters {
        field: "table_name"
        path_template: "{table_name=projects/*/instances/*/tables/*}"
      }
      routing_parameters { field: "app_profile_id" }
    };
    option (google.api.method_signature) =
        "table_name,row_key,predicate_filter,true_mutations,false_mutations";
    option (google.api.method_signature) =
        "table_name,row_key,predicate_filter,true_mutations,false_mutations,app_profile_id";
  }

  // Warm up associated instance metadata for this connection.
  // This call is not required but may be useful for connection keep-alive.
  rpc PingAndWarm(PingAndWarmRequest) returns (PingAndWarmResponse) {
    option (google.api.http) = {
      post: "/v2/{name=projects/*/instances/*}:ping"
      body: "*"
    };
    option (google.api.routing) = {
      routing_parameters {
        field: "name"
        path_template: "{name=projects/*/instances/*}"
      }
      routing_parameters { field: "app_profile_id" }
    };
    option (google.api.method_signature) = "name";
    option (google.api.method_signature) = "name,app_profile_id";
  }

  // Modifies a row atomically on the server. The method reads the latest
  // existing timestamp and value from the specified columns and writes a new
  // entry based on pre-defined read/modify/write rules. The new value for the
  // timestamp is the greater of the existing timestamp or the current server
  // time. The method returns the new contents of all modified cells.
  rpc ReadModifyWriteRow(ReadModifyWriteRowRequest)
      returns (ReadModifyWriteRowResponse) {
    option (google.api.http) = {
      post: "/v2/{table_name=projects/*/instances/*/tables/*}:readModifyWriteRow"
      body: "*"
    };
    option (google.api.routing) = {
      routing_parameters {
        field: "table_name"
        path_template: "{table_name=projects/*/instances/*/tables/*}"
      }
      routing_parameters { field: "app_profile_id" }
    };
    option (google.api.method_signature) = "table_name,row_key,rules";
    option (google.api.method_signature) =
        "table_name,row_key,rules,app_profile_id";
  }

  // NOTE: This API is intended to be used by Apache Beam BigtableIO.
  // Returns the current list of partitions that make up the table's
  // change stream. The union of partitions will cover the entire keyspace.
  // Partitions can be read with `ReadChangeStream`.
  rpc GenerateInitialChangeStreamPartitions(
      GenerateInitialChangeStreamPartitionsRequest)
      returns (stream GenerateInitialChangeStreamPartitionsResponse) {
    option (google.api.http) = {
      post: "/v2/{table_name=projects/*/instances/*/tables/*}:generateInitialChangeStreamPartitions"
      body: "*"
    };
    option (google.api.method_signature) = "table_name";
    option (google.api.method_signature) = "table_name,app_profile_id";
  }

  // NOTE: This API is intended to be used by Apache Beam BigtableIO.
  // Reads changes from a table's change stream. Changes will
  // reflect both user-initiated mutations and mutations that are caused by
  // garbage collection.
  rpc ReadChangeStream(ReadChangeStreamRequest)
      returns (stream ReadChangeStreamResponse) {
    option (google.api.http) = {
      post: "/v2/{table_name=projects/*/instances/*/tables/*}:readChangeStream"
      body: "*"
    };
    option (google.api.method_signature) = "table_name";
    option (google.api.method_signature) = "table_name,app_profile_id";
  }
}

// Request message for Bigtable.ReadRows.
message ReadRowsRequest {
  // The desired view into RequestStats that should be returned in the response.
  //
  // See also: RequestStats message.
  enum RequestStatsView {
    // The default / unset value. The API will default to the NONE option below.
    REQUEST_STATS_VIEW_UNSPECIFIED = 0;

    // Do not include any RequestStats in the response. This will leave the
    // RequestStats embedded message unset in the response.
    REQUEST_STATS_NONE = 1;

    // Include the full set of available RequestStats in the response,
    // applicable to this read.
    REQUEST_STATS_FULL = 2;
  }

  // Required. The unique name of the table from which to read.
  // Values are of the form
  // `projects/<project>/instances/<instance>/tables/<table>`.
  string table_name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Table"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  string app_profile_id = 5;

  // The row keys and/or ranges to read sequentially. If not specified, reads
  // from all rows.
  RowSet rows = 2;

  // The filter to apply to the contents of the specified row(s). If unset,
  // reads the entirety of each row.
  RowFilter filter = 3;

  // The read will stop after committing to N rows' worth of results. The
  // default (zero) is to return all results.
  int64 rows_limit = 4;

  // The view into RequestStats, as described above.
  RequestStatsView request_stats_view = 6;
}

// Response message for Bigtable.ReadRows.
message ReadRowsResponse {
  // Specifies a piece of a row's contents returned as part of the read
  // response stream.
  message CellChunk {
    // The row key for this chunk of data.  If the row key is empty,
    // this CellChunk is a continuation of the same row as the previous
    // CellChunk in the response stream, even if that CellChunk was in a
    // previous ReadRowsResponse message.
    bytes row_key = 1;

    // The column family name for this chunk of data.  If this message
    // is not present this CellChunk is a continuation of the same column
    // family as the previous CellChunk.  The empty string can occur as a
    // column family name in a response so clients must check
    // explicitly for the presence of this message, not just for
    // `family_name.value` being non-empty.
    google.protobuf.StringValue family_name = 2;

    // The column qualifier for this chunk of data.  If this message
    // is not present, this CellChunk is a continuation of the same column
    // as the previous CellChunk.  Column qualifiers may be empty so
    // clients must check for the presence of this message, not just
    // for `qualifier.value` being non-empty.
    google.protobuf.BytesValue qualifier = 3;

    // The cell's stored timestamp, which also uniquely identifies it
    // within its column.  Values are always expressed in
    // microseconds, but individual tables may set a coarser
    // granularity to further restrict the allowed values. For
    // example, a table which specifies millisecond granularity will
    // only allow values of `timestamp_micros` which are multiples of
    // 1000.  Timestamps are only set in the first CellChunk per cell
    // (for cells split into multiple chunks).
    int64 timestamp_micros = 4;

    // Labels applied to the cell by a
    // [RowFilter][google.bigtable.v2.RowFilter].  Labels are only set
    // on the first CellChunk per cell.
    repeated string labels = 5;

    // The value stored in the cell.  Cell values can be split across
    // multiple CellChunks.  In that case only the value field will be
    // set in CellChunks after the first: the timestamp and labels
    // will only be present in the first CellChunk, even if the first
    // CellChunk came in a previous ReadRowsResponse.
    bytes value = 6;

    // If this CellChunk is part of a chunked cell value and this is
    // not the final chunk of that cell, value_size will be set to the
    // total length of the cell value.  The client can use this size
    // to pre-allocate memory to hold the full cell value.
    int32 value_size = 7;

    // Signals to the client concerning previous CellChunks received.
    oneof row_status {
      // Indicates that the client should drop all previous chunks for
      // `row_key`, as it will be re-read from the beginning.
      bool reset_row = 8;

      // Indicates that the client can safely process all previous chunks for
      // `row_key`, as its data has been fully read.
      bool commit_row = 9;
    }
  }

  // A collection of a row's contents as part of the read request.
  repeated CellChunk chunks = 1;

  // Optionally the server might return the row key of the last row it
  // has scanned.  The client can use this to construct a more
  // efficient retry request if needed: any row keys or portions of
  // ranges less than this row key can be dropped from the request.
  // This is primarily useful for cases where the server has read a
  // lot of data that was filtered out since the last committed row
  // key, allowing the client to skip that work on a retry.
  bytes last_scanned_row_key = 2;

  //
  // If requested, provide enhanced query performance statistics. The semantics
  // dictate:
  //   * request_stats is empty on every (streamed) response, except
  //   * request_stats has non-empty information after all chunks have been
  //     streamed, where the ReadRowsResponse message only contains
  //     request_stats.
  //       * For example, if a read request would have returned an empty
  //         response instead a single ReadRowsResponse is streamed with empty
  //         chunks and request_stats filled.
  //
  // Visually, response messages will stream as follows:
  //    ... -> {chunks: [...]} -> {chunks: [], request_stats: {...}}
  //   \______________________/  \________________________________/
  //       Primary response         Trailer of RequestStats info
  //
  // Or if the read did not return any values:
  //   {chunks: [], request_stats: {...}}
  //   \________________________________/
  //      Trailer of RequestStats info
  RequestStats request_stats = 3;
}

// Request message for Bigtable.SampleRowKeys.
message SampleRowKeysRequest {
  // Required. The unique name of the table from which to sample row keys.
  // Values are of the form
  // `projects/<project>/instances/<instance>/tables/<table>`.
  string table_name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Table"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  string app_profile_id = 2;
}

// Response message for Bigtable.SampleRowKeys.
message SampleRowKeysResponse {
  // Sorted streamed sequence of sample row keys in the table. The table might
  // have contents before the first row key in the list and after the last one,
  // but a key containing the empty string indicates "end of table" and will be
  // the last response given, if present.
  // Note that row keys in this list may not have ever been written to or read
  // from, and users should therefore not make any assumptions about the row key
  // structure that are specific to their use case.
  bytes row_key = 1;

  // Approximate total storage space used by all rows in the table which precede
  // `row_key`. Buffering the contents of all rows between two subsequent
  // samples would require space roughly equal to the difference in their
  // `offset_bytes` fields.
  int64 offset_bytes = 2;
}

// Request message for Bigtable.MutateRow.
message MutateRowRequest {
  // Required. The unique name of the table to which the mutation should be
  // applied. Values are of the form
  // `projects/<project>/instances/<instance>/tables/<table>`.
  string table_name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Table"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  string app_profile_id = 4;

  // Required. The key of the row to which the mutation should be applied.
  bytes row_key = 2 [(google.api.field_behavior) = REQUIRED];

  // Required. Changes to be atomically applied to the specified row. Entries
  // are applied in order, meaning that earlier mutations can be masked by later
  // ones. Must contain at least one entry and at most 100000.
  repeated Mutation mutations = 3 [(google.api.field_behavior) = REQUIRED];
}

// Response message for Bigtable.MutateRow.
message MutateRowResponse {}

// Request message for BigtableService.MutateRows.
message MutateRowsRequest {
  // A mutation for a given row.
  message Entry {
    // The key of the row to which the `mutations` should be applied.
    bytes row_key = 1;

    // Required. Changes to be atomically applied to the specified row.
    // Mutations are applied in order, meaning that earlier mutations can be
    // masked by later ones. You must specify at least one mutation.
    repeated Mutation mutations = 2 [(google.api.field_behavior) = REQUIRED];
  }

  // Required. The unique name of the table to which the mutations should be
  // applied.
  string table_name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Table"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  string app_profile_id = 3;

  // Required. The row keys and corresponding mutations to be applied in bulk.
  // Each entry is applied as an atomic mutation, but the entries may be
  // applied in arbitrary order (even between entries for the same row).
  // At least one entry must be specified, and in total the entries can
  // contain at most 100000 mutations.
  repeated Entry entries = 2 [(google.api.field_behavior) = REQUIRED];
}

// Response message for BigtableService.MutateRows.
message MutateRowsResponse {
  // The result of applying a passed mutation in the original request.
  message Entry {
    // The index into the original request's `entries` list of the Entry
    // for which a result is being reported.
    int64 index = 1;

    // The result of the request Entry identified by `index`.
    // Depending on how requests are batched during execution, it is possible
    // for one Entry to fail due to an error with another Entry. In the event
    // that this occurs, the same error will be reported for both entries.
    google.rpc.Status status = 2;
  }

  // One or more results for Entries from the batch request.
  repeated Entry entries = 1;

  // Information about how client should limit the rate (QPS). Primirily used by
  // supported official Cloud Bigtable clients. If unset, the rate limit info is
  // not provided by the server.
  optional RateLimitInfo rate_limit_info = 3;
}

// Information about how client should adjust the load to Bigtable.
message RateLimitInfo {
  // Time that clients should wait before adjusting the target rate again.
  // If clients adjust rate too frequently, the impact of the previous
  // adjustment may not have been taken into account and may
  // over-throttle or under-throttle. If clients adjust rate too slowly, they
  // will not be responsive to load changes on server side, and may
  // over-throttle or under-throttle.
  google.protobuf.Duration period = 1;

  // If it has been at least one `period` since the last load adjustment, the
  // client should multiply the current load by this value to get the new target
  // load. For example, if the current load is 100 and `factor` is 0.8, the new
  // target load should be 80. After adjusting, the client should ignore
  // `factor` until another `period` has passed.
  //
  // The client can measure its load using any unit that's comparable over time
  // For example, QPS can be used as long as each request involves a similar
  // amount of work.
  double factor = 2;
}

// Request message for Bigtable.CheckAndMutateRow.
message CheckAndMutateRowRequest {
  // Required. The unique name of the table to which the conditional mutation
  // should be applied. Values are of the form
  // `projects/<project>/instances/<instance>/tables/<table>`.
  string table_name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Table"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  string app_profile_id = 7;

  // Required. The key of the row to which the conditional mutation should be
  // applied.
  bytes row_key = 2 [(google.api.field_behavior) = REQUIRED];

  // The filter to be applied to the contents of the specified row. Depending
  // on whether or not any results are yielded, either `true_mutations` or
  // `false_mutations` will be executed. If unset, checks that the row contains
  // any values at all.
  RowFilter predicate_filter = 6;

  // Changes to be atomically applied to the specified row if `predicate_filter`
  // yields at least one cell when applied to `row_key`. Entries are applied in
  // order, meaning that earlier mutations can be masked by later ones.
  // Must contain at least one entry if `false_mutations` is empty, and at most
  // 100000.
  repeated Mutation true_mutations = 4;

  // Changes to be atomically applied to the specified row if `predicate_filter`
  // does not yield any cells when applied to `row_key`. Entries are applied in
  // order, meaning that earlier mutations can be masked by later ones.
  // Must contain at least one entry if `true_mutations` is empty, and at most
  // 100000.
  repeated Mutation false_mutations = 5;
}

// Response message for Bigtable.CheckAndMutateRow.
message CheckAndMutateRowResponse {
  // Whether or not the request's `predicate_filter` yielded any results for
  // the specified row.
  bool predicate_matched = 1;
}

// Request message for client connection keep-alive and warming.
message PingAndWarmRequest {
  // Required. The unique name of the instance to check permissions for as well
  // as respond. Values are of the form
  // `projects/<project>/instances/<instance>`.
  string name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Instance"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  string app_profile_id = 2;
}

// Response message for Bigtable.PingAndWarm connection keepalive and warming.
message PingAndWarmResponse {}

// Request message for Bigtable.ReadModifyWriteRow.
message ReadModifyWriteRowRequest {
  // Required. The unique name of the table to which the read/modify/write rules
  // should be applied. Values are of the form
  // `projects/<project>/instances/<instance>/tables/<table>`.
  string table_name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Table"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  string app_profile_id = 4;

  // Required. The key of the row to which the read/modify/write rules should be
  // applied.
  bytes row_key = 2 [(google.api.field_behavior) = REQUIRED];

  // Required. Rules specifying how the specified row's contents are to be
  // transformed into writes. Entries are applied in order, meaning that earlier
  // rules will affect the results of later ones.
  repeated ReadModifyWriteRule rules = 3
      [(google.api.field_behavior) = REQUIRED];
}

// Response message for Bigtable.ReadModifyWriteRow.
message ReadModifyWriteRowResponse {
  // A Row containing the new contents of all cells modified by the request.
  Row row = 1;
}

// NOTE: This API is intended to be used by Apache Beam BigtableIO.
// Request message for Bigtable.GenerateInitialChangeStreamPartitions.
message GenerateInitialChangeStreamPartitionsRequest {
  // Required. The unique name of the table from which to get change stream
  // partitions. Values are of the form
  // `projects/<project>/instances/<instance>/tables/<table>`.
  // Change streaming must be enabled on the table.
  string table_name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Table"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  // Single cluster routing must be configured on the profile.
  string app_profile_id = 2;
}

// NOTE: This API is intended to be used by Apache Beam BigtableIO.
// Response message for Bigtable.GenerateInitialChangeStreamPartitions.
message GenerateInitialChangeStreamPartitionsResponse {
  // A partition of the change stream.
  StreamPartition partition = 1;
}

// NOTE: This API is intended to be used by Apache Beam BigtableIO.
// Request message for Bigtable.ReadChangeStream.
message ReadChangeStreamRequest {
  // Required. The unique name of the table from which to read a change stream.
  // Values are of the form
  // `projects/<project>/instances/<instance>/tables/<table>`.
  // Change streaming must be enabled on the table.
  string table_name = 1 [
    (google.api.field_behavior) = REQUIRED,
    (google.api.resource_reference) = {
      type: "bigtableadmin.googleapis.com/Table"
    }
  ];

  // This value specifies routing for replication. If not specified, the
  // "default" application profile will be used.
  // Single cluster routing must be configured on the profile.
  string app_profile_id = 2;

  // The partition to read changes from.
  StreamPartition partition = 3;

  // Options for describing where we want to start reading from the stream.
  oneof start_from {
    // Start reading the stream at the specified timestamp. This timestamp must
    // be within the change stream retention period, less than or equal to the
    // current time, and after change stream creation, whichever is greater.
    // This value is inclusive and will be truncated to microsecond granularity.
    google.protobuf.Timestamp start_time = 4;

    // Tokens that describe how to resume reading a stream where reading
    // previously left off. If specified, changes will be read starting at the
    // the position. Tokens are delivered on the stream as part of `Heartbeat`
    // and `CloseStream` messages.
    //
    // If a single token is provided, the token’s partition must exactly match
    // the request’s partition. If multiple tokens are provided, as in the case
    // of a partition merge, the union of the token partitions must exactly
    // cover the request’s partition. Otherwise, INVALID_ARGUMENT will be
    // returned.
    StreamContinuationTokens continuation_tokens = 6;
  }

  // If specified, OK will be returned when the stream advances beyond
  // this time. Otherwise, changes will be continuously delivered on the stream.
  // This value is inclusive and will be truncated to microsecond granularity.
  google.protobuf.Timestamp end_time = 5;

  // If specified, the duration between `Heartbeat` messages on the stream.
  // Otherwise, defaults to 5 seconds.
  google.protobuf.Duration heartbeat_duration = 7;
}

// NOTE: This API is intended to be used by Apache Beam BigtableIO.
// Response message for Bigtable.ReadChangeStream.
message ReadChangeStreamResponse {
  // A partial or complete mutation.
  message MutationChunk {
    // Information about the chunking of this mutation.
    // Only `SetCell` mutations can be chunked, and all chunks for a `SetCell`
    // will be delivered contiguously with no other mutation types interleaved.
    message ChunkInfo {
      // The total value size of all the chunks that make up the `SetCell`.
      int32 chunked_value_size = 1;

      // The byte offset of this chunk into the total value size of the
      // mutation.
      int32 chunked_value_offset = 2;

      // When true, this is the last chunk of a chunked `SetCell`.
      bool last_chunk = 3;
    }

    // If set, then the mutation is a `SetCell` with a chunked value across
    // multiple messages.
    ChunkInfo chunk_info = 1;

    // If this is a continuation of a chunked message (`chunked_value_offset` >
    // 0), ignore all fields except the `SetCell`'s value and merge it with
    // the previous message by concatenating the value fields.
    Mutation mutation = 2;
  }

  // A message corresponding to one or more mutations to the partition
  // being streamed. A single logical `DataChange` message may also be split
  // across a sequence of multiple individual messages. Messages other than
  // the first in a sequence will only have the `type` and `chunks` fields
  // populated, with the final message in the sequence also containing `done`
  // set to true.
  message DataChange {
    // The type of mutation.
    enum Type {
      // The type is unspecified.
      TYPE_UNSPECIFIED = 0;

      // A user-initiated mutation.
      USER = 1;

      // A system-initiated mutation as part of garbage collection.
      // https://cloud.google.com/bigtable/docs/garbage-collection
      GARBAGE_COLLECTION = 2;

      // This is a continuation of a multi-message change.
      CONTINUATION = 3;
    }

    // The type of the mutation.
    Type type = 1;

    // The cluster where the mutation was applied.
    // Not set when `type` is `GARBAGE_COLLECTION`.
    string source_cluster_id = 2;

    // The row key for all mutations that are part of this `DataChange`.
    // If the `DataChange` is chunked across multiple messages, then this field
    // will only be set for the first message.
    bytes row_key = 3;

    // The timestamp at which the mutation was applied on the Bigtable server.
    google.protobuf.Timestamp commit_timestamp = 4;

    // A value that lets stream consumers reconstruct Bigtable's
    // conflict resolution semantics.
    // https://cloud.google.com/bigtable/docs/writes#conflict-resolution
    // In the event that the same row key, column family, column qualifier,
    // timestamp are modified on different clusters at the same
    // `commit_timestamp`, the mutation with the larger `tiebreaker` will be the
    // one chosen for the eventually consistent state of the system.
    int32 tiebreaker = 5;

    // The mutations associated with this change to the partition.
    // May contain complete mutations or chunks of a multi-message chunked
    // `DataChange` record.
    repeated MutationChunk chunks = 6;

    // When true, indicates that the entire `DataChange` has been read
    // and the client can safely process the message.
    bool done = 8;

    // An encoded position for this stream's partition to restart reading from.
    // This token is for the StreamPartition from the request.
    string token = 9;

    // An estimate of the commit timestamp that is usually lower than or equal
    // to any timestamp for a record that will be delivered in the future on the
    // stream. It is possible that, under particular circumstances that a future
    // record has a timestamp is is lower than a previously seen timestamp. For
    // an example usage see
    // https://beam.apache.org/documentation/basics/#watermarks
    google.protobuf.Timestamp estimated_low_watermark = 10;
  }

  // A periodic message with information that can be used to checkpoint
  // the state of a stream.
  message Heartbeat {
    // A token that can be provided to a subsequent `ReadChangeStream` call
    // to pick up reading at the current stream position.
    StreamContinuationToken continuation_token = 1;

    // An estimate of the commit timestamp that is usually lower than or equal
    // to any timestamp for a record that will be delivered in the future on the
    // stream. It is possible that, under particular circumstances that a future
    // record has a timestamp is is lower than a previously seen timestamp. For
    // an example usage see
    // https://beam.apache.org/documentation/basics/#watermarks
    google.protobuf.Timestamp estimated_low_watermark = 2;
  }

  // A message indicating that the client should stop reading from the stream.
  // If status is OK and `continuation_tokens` & `new_partitions` are empty, the
  // stream has finished (for example if there was an `end_time` specified).
  // If `continuation_tokens` & `new_partitions` are present, then a change in
  // partitioning requires the client to open a new stream for each token to
  // resume reading. Example:
  //                                  [B,      D) ends
  //                                       |
  //                                       v
  //               new_partitions:  [A,  C) [C,  E)
  // continuation_tokens.partitions:  [B,C) [C,D)
  //                                  ^---^ ^---^
  //                                  ^     ^
  //                                  |     |
  //                                  |     StreamContinuationToken 2
  //                                  |
  //                                  StreamContinuationToken 1
  // To read the new partition [A,C), supply the continuation tokens whose
  // ranges cover the new partition, for example ContinuationToken[A,B) &
  // ContinuationToken[B,C).
  message CloseStream {
    // The status of the stream.
    google.rpc.Status status = 1;

    // If non-empty, contains the information needed to resume reading their
    // associated partitions.
    repeated StreamContinuationToken continuation_tokens = 2;

    // If non-empty, contains the new partitions to start reading from, which
    // are related to but not necessarily identical to the partitions for the
    // above `continuation_tokens`.
    repeated StreamPartition new_partitions = 3;
  }

  // The data or control message on the stream.
  oneof stream_record {
    // A mutation to the partition.
    DataChange data_change = 1;

    // A periodic heartbeat message.
    Heartbeat heartbeat = 2;

    // An indication that the stream should be closed.
    CloseStream close_stream = 3;
  }
}