/*
Copyright 2019 The Vitess Authors.

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.
*/

// This file contains the Vitess topology related data structures.
// Very few of these structures are exchanged over the wire (only
// TabletType and KeyRange), but they are all used by the topology
// service.

syntax = "proto3";
option go_package = "vitess.io/vitess/go/vt/proto/topodata";

option java_package="io.vitess.proto";

package topodata;

import "vttime.proto";

// KeyRange describes a range of sharding keys, when range-based
// sharding is used.
message KeyRange {
  bytes start = 1;
  bytes end = 2;
}

// KeyspaceType describes the type of the keyspace
enum KeyspaceType {
  // NORMAL is the default value
  NORMAL = 0;

  // SNAPSHOT is when we are creating a snapshot keyspace
  SNAPSHOT = 1;
}

// TabletAlias is a globally unique tablet identifier.
message TabletAlias {
  // cell is the cell (or datacenter) the tablet is in
  string cell = 1;

  // uid is a unique id for this tablet within the shard
  // (this is the MySQL server id as well).
  uint32 uid = 2;
}

// TabletType represents the type of a given tablet.
enum TabletType {
  option allow_alias = true; // so we can have RDONLY and BATCH co-exist

  // UNKNOWN is not a valid value.
  UNKNOWN = 0;

  // PRIMARY is the primary server for the shard. Only PRIMARY allows DMLs.
  PRIMARY = 1;

  // DEPRECATED
  MASTER = 1;

  // REPLICA replicates from primary. It is used to serve live traffic.
  // A REPLICA can be promoted to PRIMARY. A demoted PRIMARY will go to REPLICA.
  REPLICA = 2;

  // RDONLY (old name) / BATCH (new name) is used to serve traffic for
  // long-running jobs. It is a separate type from REPLICA so
  // long-running queries don't affect web-like traffic.
  RDONLY = 3;
  BATCH = 3;

  // SPARE is a type of servers that cannot serve queries, but is available
  // in case an extra server is needed.
  SPARE = 4;

  // EXPERIMENTAL is like SPARE, except it can serve queries. This
  // type can be used for usages not planned by Vitess, like online
  // export to another storage engine.
  EXPERIMENTAL = 5;

  // BACKUP is the type a server goes to when taking a backup. No queries
  // can be served in BACKUP mode.
  BACKUP = 6;

  // RESTORE is the type a server uses when restoring a backup, at
  // startup time.  No queries can be served in RESTORE mode.
  RESTORE = 7;

  // DRAINED is the type a server goes into when used by Vitess tools
  // to perform an offline action. It is a serving type (as
  // the tools processes may need to run queries), but it's not used
  // to route queries from Vitess users. In this state,
  // this tablet is dedicated to the process that uses it.
  DRAINED = 8;
}

// Tablet represents information about a running instance of vttablet.
message Tablet {
  // alias is the unique name of the tablet.
  TabletAlias alias = 1;

  // Fully qualified domain name of the host.
  string hostname = 2;

  // Map of named ports. Normally this should include vt and grpc.
  // Going forward, the mysql port will be stored in mysql_port
  // instead of here.
  // For accessing mysql port, use topoproto.MysqlPort to fetch, and
  // topoproto.SetMysqlPort to set. These wrappers will ensure
  // legacy behavior is supported.
  map<string, int32> port_map = 4;

  // Keyspace name.
  string keyspace = 5;

  // Shard name. If range based sharding is used, it should match
  // key_range.
  string shard = 6;

  // If range based sharding is used, range for the tablet's shard.
  KeyRange key_range = 7;

  // type is the current type of the tablet.
  TabletType type = 8;

  // It this is set, it is used as the database name instead of the
  // normal "vt_" + keyspace.
  string db_name_override = 9;

  // tablet tags
  map<string, string> tags = 10;

  // MySQL hostname.
  string mysql_hostname = 12;

  // MySQL port. Use topoproto.MysqlPort and topoproto.SetMysqlPort
  // to access this variable. The functions provide support
  // for legacy behavior.
  int32 mysql_port = 13;

  // primary_term_start_time is the time (in UTC) at which the current term of
  // the current tablet began as primary. If this tablet is not currently the
  // primary, this value is ignored.
  //
  // A new primary term begins any time an authoritative decision is communicated
  // about which tablet should be the primary, such as via Vitess
  // replication-management commands like PlannedReparentShard,
  // EmergencyReparentShard, and TabletExternallyReparented.
  //
  vttime.Time primary_term_start_time = 14;

  // default_conn_collation is the default connection collation used by this tablet.
  uint32 default_conn_collation = 16;

  // OBSOLETE: ip and tablet health information
  // string ip = 3;
  // map<string, string> health_map = 11;
  // string db_server_version = 15;
  reserved 3, 11, 15;
}

// A Shard contains data about a subset of the data whithin a keyspace.
message Shard {
  // primary_alias is the tablet alias of the primary for the shard.
  // If it is unset, then there is no primary in this shard yet.
  // No lock is necessary to update this field, when for instance
  // TabletExternallyReparented updates this. However, we lock the
  // shard for reparenting operations (InitShardPrimary,
  // PlannedReparentShard,EmergencyReparentShard), to guarantee
  // exclusive operation.
  TabletAlias primary_alias = 1;

  // primary_term_start_time is the time (in UTC) at which the current term of
  // the primary specified in primary_alias began.
  //
  // A new primary term begins any time an authoritative decision is communicated
  // about which tablet should be the primary, such as via Vitess
  // replication-management commands like PlannedReparentShard,
  // EmergencyReparentShard, and TabletExternallyReparented.
  //
  // The primary_alias should only ever be changed if the new primary's term began
  // at a later time than this. Note that a new term can start for the tablet
  // that is already the primary. In that case, the primary_term_start_time would
  // be increased without changing the primary_alias.
  vttime.Time primary_term_start_time = 8;

  // key_range is the KeyRange for this shard. It can be unset if:
  // - we are not using range-based sharding in this shard.
  // - the shard covers the entire keyrange.
  // This must match the shard name based on our other conventions, but
  // helpful to have it decomposed here.
  // Once set at creation time, it is never changed.
  KeyRange key_range = 2;

  // Deprecated: served_types = 3
  reserved 3;

  // SourceShard represents a data source for filtered replication
  // across shards. When this is used in a destination shard, the primary
  // of that shard will run filtered replication.
  message SourceShard {
    // Uid is the unique ID for this SourceShard object.
    int32 uid = 1;

    // the source keyspace
    string keyspace = 2;

    // the source shard
    string shard = 3;

    // the source shard keyrange
    KeyRange key_range = 4;

    // the source table list to replicate
    repeated string tables = 5;
  }

  // SourceShards is the list of shards we're replicating from,
  // using filtered replication.
  // The keyspace lock is always taken when changing this.
  repeated SourceShard source_shards = 4;

  // TabletControl controls tablet's behavior
  message TabletControl {
    // which tablet type is affected
    TabletType tablet_type = 1;
    repeated string cells = 2;

    // OBSOLETE: disable_query_service 3
    reserved 3;

    repeated string denied_tables = 4;

    // frozen is set if we've started failing over traffic for
    // the primary. If set, this record should not be removed.
    bool frozen = 5;
  }

  // tablet_controls has at most one entry per TabletType.
  // The keyspace lock is always taken when changing this.
  repeated TabletControl tablet_controls = 6;

  // is_primary_serving sets whether this shard primary is serving traffic or not.
  // The keyspace lock is always taken when changing this.
  bool is_primary_serving = 7;

  // OBSOLETE cells (5)
  reserved 5;
}

// A Keyspace contains data about a keyspace.
message Keyspace {
  // OBSOLETE string sharding_column_name = 1;
  reserved 1;

  // OBSOLETE KeyspaceIdType sharding_column_type = 2;
  reserved 2;

  // OBSOLETE int32 split_shard_count = 3;
  reserved 3;

  // ServedFrom indicates a relationship between a TabletType and the
  // keyspace name that's serving it.
  message ServedFrom {
    // the tablet type (key for the map)
    TabletType tablet_type = 1;

    // the cells to limit this to
    repeated string cells = 2;

    // the keyspace name that's serving it
    string keyspace = 3;
  }

  // ServedFrom will redirect the appropriate traffic to
  // another keyspace.
  repeated ServedFrom served_froms = 4;

  // keyspace_type will determine how this keyspace is treated by
  // vtgate / vschema. Normal keyspaces are routable by
  // any query. Snapshot keyspaces are only accessible
  // by explicit addresssing or by calling "use keyspace" first
  KeyspaceType keyspace_type = 5;

  // base_keyspace is the base keyspace from which a snapshot
  // keyspace is created. empty for normal keyspaces
  string base_keyspace = 6;
  
  // snapshot_time (in UTC) is a property of snapshot
  // keyspaces which tells us what point in time
  // the snapshot is of
  vttime.Time snapshot_time = 7;

  // DurabilityPolicy is the durability policy to be
  // used for the keyspace.
  string durability_policy = 8;

  // ThrottlerConfig has the configuration for the tablet
  // server's lag throttler, and applies to the entire
  // keyspace, across all shards and tablets.
  ThrottlerConfig throttler_config = 9;

  // SidecarDBName is the name of the Vitess sidecar database
  // used for various system metadata that is stored in each
  // tablet's mysqld instance.
  string sidecar_db_name = 10;
}

// ShardReplication describes the MySQL replication relationships
// whithin a cell.
message ShardReplication {

  // Node describes a tablet instance within the cell
  message Node {
    TabletAlias tablet_alias = 1;
  }

  // Note there can be only one Node in this array
  // for a given tablet.
  repeated Node nodes = 1;
}

// ShardReplicationError describes the error being fixed by
// ShardReplicationFix.
message ShardReplicationError {
  enum Type {
    // UNKNOWN is not a valid value.
    UNKNOWN = 0;
    // NOT_FOUND occurs when a tablet is in the ShardReplication record
    // but does not exist in the topology.
    NOT_FOUND = 1;
    // TOPOLOGY_MISMATCH occurs when a tablet is in the replication graph and
    // exists in the topology, but at least one of the Keyspace, Shard, or Cell
    // fields for that tablet does not match the ShardReplication record.
    TOPOLOGY_MISMATCH = 2;
  }

  // Type is the category of problem being fixed.
  Type type = 1;
  // TabletAlias is the tablet record that has the problem.
  topodata.TabletAlias tablet_alias = 2;
}

// ShardReference is used as a pointer from a SrvKeyspace to a Shard
message ShardReference {
  // Copied from Shard.
  string name = 1;
  KeyRange key_range = 2;
  // Disable query serving in this shard
}

// ShardTabletControl is used as a pointer from a SrvKeyspace to a Shard
message ShardTabletControl {
  // Copied from Shard.
  string name = 1;
  KeyRange key_range = 2;
  // Disable query serving in this shard
  bool query_service_disabled = 3;
}

// ThrottledAppRule defines an app-specific throttling rule, with expiration.
message ThrottledAppRule {
  // Name of the app to be throttled, e.g. "vreplication" or "online-ddl"
  string name = 1;
  // Ratio defines how much the app should be throttled, range [0.0...1.0]. 1.0 means fully throttled. 0.0 means not throttled at all.
  // Negative values are reserved for a future implementation.
  double ratio = 2;
  // ExpiresAt is the time at which the rule expires.
  vttime.Time expires_at = 3;
  // Exempt indicates the app should never be throttled, even if the throttler is, in general, throttling other apps.
  bool exempt = 4;
}

message ThrottlerConfig {
  // Enabled indicates that the throttler is actually checking state for
  // requests. When disabled, it automatically returns 200 OK for all
  // checks.
  bool enabled = 1;

  // Threshold is the threshold for either the default check (heartbeat
  // lag) or custom check.
  double threshold = 2;

  // CustomQuery is an optional query that overrides the default check
  // query.
  string custom_query = 3;

  // CheckAsCheckSelf indicates whether a throttler /check request
  // should behave like a /check-self.
  bool check_as_check_self = 4;

  // ThrottledApps is a map of rules for app-specific throttling
  map<string, ThrottledAppRule> throttled_apps = 5;
}

// SrvKeyspace is a rollup node for the keyspace itself.
message SrvKeyspace {
  message KeyspacePartition {
    // The type this partition applies to.
    TabletType served_type = 1;

    // List of non-overlapping continuous shards sorted by range.
    repeated ShardReference shard_references = 2;

    // List of shard tablet controls
    repeated ShardTabletControl shard_tablet_controls = 3;
  }

  // The partitions this keyspace is serving, per tablet type.
  repeated KeyspacePartition partitions = 1;

  // ServedFrom indicates a relationship between a TabletType and the
  // keyspace name that's serving it.
  message ServedFrom {
    // the tablet type
    TabletType tablet_type = 1;

    // the keyspace name that's serving it
    string keyspace = 2;
  }

  // copied from Keyspace
  // OBSOLETE string sharding_column_name = 2;
  reserved 2;

  // OBSOLETE KeyspaceIdType sharding_column_type = 3;
  reserved 3;

  repeated ServedFrom served_from = 4;

  // OBSOLETE int32 split_shard_count = 5;
  reserved 5;

  // ThrottlerConfig has the configuration for the tablet server's
  // lag throttler, and applies to the entire keyspace, across all
  // shards and tablets. This is copied from the global keyspace
  // object.
  ThrottlerConfig throttler_config = 6;
}

// CellInfo contains information about a cell. CellInfo objects are
// stored in the global topology server, and describe how to reach
// local topology servers.
message CellInfo {
  // ServerAddress contains the address of the server for the cell.
  // The syntax of this field is topology implementation specific.
  // For instance, for Zookeeper, it is a comma-separated list of
  // server addresses.
  string server_address = 1;

  // Root is the path to store data in. It is only used when talking
  // to server_address.
  string root = 2;

  // OBSOLETE: region 3
  reserved 3;
}

// CellsAlias 
message CellsAlias {
  // Cells that map to this alias
  repeated string cells = 2;
}

message TopoConfig {
  string topo_type = 1;
  string server = 2;
  string root = 3;
}

message ExternalVitessCluster {
  TopoConfig topo_config = 1;
}

// ExternalClusters
message ExternalClusters {
  repeated ExternalVitessCluster vitess_cluster = 1;
}