ShardCoordinator
Defined in: src/cluster/sharding/ShardCoordinator.ts:130
Cluster-wide authoritative source of shard-to-region assignments. Runs on every node but only responds to requests when the local node is the cluster leader. Non-leader coordinators ignore incoming messages so that duplicate coordinators during a leader transition are harmless.
State is reconstructed from Register messages: each region reports the shards it currently hosts, and the coordinator merges that with any new allocation requests. This is deliberately lightweight — a production upgrade would snapshot state to a journal so the coordinator can recover across restarts without re-allocating every shard from scratch.
Extends
Section titled “Extends”Actor<CoordinatorInbox>
Constructors
Section titled “Constructors”Constructor
Section titled “Constructor”new ShardCoordinator(
settings):ShardCoordinator
Defined in: src/cluster/sharding/ShardCoordinator.ts:185
Parameters
Section titled “Parameters”settings
Section titled “settings”Returns
Section titled “Returns”ShardCoordinator
Overrides
Section titled “Overrides”Properties
Section titled “Properties”settings
Section titled “settings”
readonlysettings:ShardCoordinatorSettings
Defined in: src/cluster/sharding/ShardCoordinator.ts:185
Methods
Section titled “Methods”onReceive()
Section titled “onReceive()”onReceive(
msg):void
Defined in: src/cluster/sharding/ShardCoordinator.ts:263
Main message handler. Receives each envelope dequeued from the mailbox. A thrown error (sync or async) is caught by the supervisor.
Parameters
Section titled “Parameters”CoordinatorInbox
Returns
Section titled “Returns”void
Overrides
Section titled “Overrides”postRestart()
Section titled “postRestart()”postRestart(
_reason):void|Promise<void>
Defined in: src/Actor.ts:55
Called on the fresh instance after a restart. Default: call preStart().
Parameters
Section titled “Parameters”_reason
Section titled “_reason”Error
Returns
Section titled “Returns”void | Promise<void>
Inherited from
Section titled “Inherited from”postStop()
Section titled “postStop()”postStop():
Promise<void>
Defined in: src/cluster/sharding/ShardCoordinator.ts:251
Called after the actor has been terminated. Children are already stopped.
Returns
Section titled “Returns”Promise<void>
Overrides
Section titled “Overrides”preRestart()
Section titled “preRestart()”preRestart(
_reason,_message?):void|Promise<void>
Defined in: src/Actor.ts:50
Called before a restart, on the instance about to be thrown away. The default stops children and then calls postStop().
Parameters
Section titled “Parameters”_reason
Section titled “_reason”Error
_message?
Section titled “_message?”CoordinatorInbox
Returns
Section titled “Returns”void | Promise<void>
Inherited from
Section titled “Inherited from”preStart()
Section titled “preStart()”preStart():
Promise<void>
Defined in: src/cluster/sharding/ShardCoordinator.ts:192
Called after construction and before the first message is processed.
Returns
Section titled “Returns”Promise<void>
Overrides
Section titled “Overrides”supervisorStrategy()
Section titled “supervisorStrategy()”supervisorStrategy():
SupervisorStrategy
Defined in: src/Actor.ts:63
Supervisor strategy for this actor’s children. Defaults to restart, up to 10 times per minute, then stop.
Returns
Section titled “Returns”Inherited from
Section titled “Inherited from”pathFor()
Section titled “pathFor()”
staticpathFor(typeName):string
Defined in: src/cluster/sharding/ShardCoordinator.ts:188
Path used by ClusterSharding to locate the coordinator on any node.
Parameters
Section titled “Parameters”typeName
Section titled “typeName”string
Returns
Section titled “Returns”string