SingleRunner

Single-process cluster layer for durable entities and workflows. It wires Sharding with no-op runner communication, no-op runner health checks, SQL-backed message storage, environment-based sharding configuration, and either SQL-backed or in-memory runner storage.

This layer is meant for local, embedded, or small single-node setups where the process handles all cluster work itself. It still requires a SQL client because mailbox messages and replies are stored in SQL.

1 exports Added in v4.0.0 Source

Layers

layer

Added in v4.0.0 Source

Provides a SQL-backed single-node cluster for running durable entities and workflows.

When to use

Use to run durable cluster entities and workflows in a local, embedded, or small single-node process while keeping mailbox and reply state in SQL.

Details

The layer provides Sharding, Runners, and MessageStorage. It loads ShardingConfig from environment variables and overlays options.shardingConfig when provided. Message storage is always SQL-backed; runner storage is SQL-backed by default and switches to in-memory storage when runnerStorage is set to "memory".

Gotchas

Even when runnerStorage is "memory", message storage remains SQL-backed, so callers must still provide SqlClient and Crypto.Crypto (used to hash over-length message deduplication keys).
Runner communication and runner health are no-op services, so this layer is for single-process use rather than multi-runner coordination.

See

ShardingConfig.layerFromEnv for loading environment configuration before applying shardingConfig overrides
SqlMessageStorage.layer for the SQL-backed message storage that this layer provides
SqlRunnerStorage.layer for the default SQL-backed runner storage selected when runnerStorage is omitted or "sql"
RunnerStorage.layerMemory for the in-memory runner storage selected by runnerStorage: "memory"

Signature

declare function layer(options?: {
  readonly runnerStorage?: "memory" | "sql";
  readonly shardingConfig?: Partial<{
    readonly assignedShardGroups: readonly Array<string>;
    readonly availableShardGroups: readonly Array<string>;
    readonly entityMailboxCapacity: number | "unbounded";
    readonly entityMaxIdleTime: Input;
    readonly entityMessagePollInterval: Input;
    readonly entityRegistrationTimeout: Input;
    readonly entityReplyPollInterval: Input;
    readonly entityTerminationTimeout: Input;
    readonly maxResidentEntities: number | "unbounded";
    readonly preemptiveShutdown: boolean;
    readonly refreshAssignmentsInterval: Input;
    readonly runnerAddress: Option<RunnerAddress>;
    readonly runnerHealthCheckInterval: Input;
    readonly runnerListenAddress: Option<RunnerAddress>;
    readonly runnerShardWeight: number;
    readonly sendRetryInterval: Input;
    readonly shardLockDisableAdvisory: boolean;
    readonly shardLockExpiration: Input;
    readonly shardLockRefreshInterval: Input;
    readonly shardsPerGroup: number;
    readonly simulateRemoteSerialization: boolean;
    readonly unprocessedMessageBatchSize: number;
  }>;
}): Layer<Sharding | MessageStorage | Runners, ConfigError, Crypto | SqlClient>