stable library

Classes

AtomicTerminalResultBackend: Optional atomic terminal-state arbitration for result backends.
BatchStatus: Durable batch status projection derived from group metadata/results.
BatchSubmission: Handle returned when a batch is submitted.
BroadcastDefinition: Broadcast channel declaration.
Broker: Abstract broker compatibility facade implemented by queue adapters.
BrokerCapabilities: Runtime-declared capabilities of a broker adapter.
BrokerCapabilitiesProvider: Optional provider interface for adapters with capability declarations that are more precise than the legacy Broker getters.
CalendarScheduleSpec: Schedule specification that matches specific calendar attributes.
Canvas: A high-level API for composing and dispatching tasks.
ChordResult<T extends Object?>: Result returned by Canvas.chord.
ClockedScheduleSpec: Schedule specification for a fixed, absolute run time.
CodecTaskPayloadEncoder<T>: Bridges a PayloadCodec into the existing TaskPayloadEncoder contract.
CronScheduleSpec: Schedule specification for standard Cron expressions.
DeadLetterBroker: Optional broker capability for dead-letter inspection and replay.
DeadLetterEntry: Dead letter queue entry containing the failed envelope and metadata.
DeadLetterPage: Page of dead letter results with optional continuation offset.
DeadLetterReplayResult: Result describing entries considered for replay.
DefaultQueueConfig: Default queue alias configuration tying alias to a canonical queue name.
EmitWorkflowEventRequest: Workflow event emit request payload for isolate communication.
EmitWorkflowEventResponse: Response payload for isolate workflow event emit requests.
EmitWorkflowEventSignal: Request to emit a workflow event from an isolate.
EnqueueTaskSignal: Request to enqueue a task from an isolate.
EventBus: Distributes external events to workflow runs.
ExponentialJitterRetryStrategy: Exponential backoff with jitter, capped at a configurable duration.
ExtendLeaseSignal: Signals a request to extend a task lease.
FakeWorkflowClock: Controllable clock intended for tests.
FencedLock: A lock handle that carries a monotonically increasing fencing token.
Flow<T extends Object?>: Convenience wrapper that builds a WorkflowDefinition using the declarative FlowBuilder DSL.
FlowBuilder: Builder used by Flow to capture workflow steps in declaration order.
FlowContext: Context provided to each workflow step invocation.
FlowStep: Node in a workflow Flow.
FlowStepControl: Control directive emitted by a workflow step to suspend execution.
GroupDescriptor: Descriptor for group (e.g., chord) aggregation.
GroupDispatch<T extends Object?>: Handle returned by Canvas.group providing a stream of typed results.
GroupStatus: Aggregated status for a group/chord.
HeartbeatSignal: Signals a heartbeat from an executing task.
InMemoryWorkflowRegistry: In-memory WorkflowRegistry implementation for local runs and tests.
InspectableBroker: Optional broker capability for queue-depth inspection.
IntervalScheduleSpec: Schedule specification for fixed time intervals.
LeaseBroker: Optional broker capability for extending active delivery leases.
Lock: Handle to a lock acquired from a LockStore.
LockStore: Lock store used for unique jobs or scheduling coordination. Since: 0.1.0
LockStoreFactory: Factory for building LockStore instances.
Middleware: Middleware hook invoked for lifecycle events around enqueue/consume/execute. Since: 0.1.0
NoArgsTaskDefinition<TResult>: Typed producer-facing definition for tasks that take no input args.
NoArgsWorkflowRef<TResult extends Object?>: Typed producer-facing reference for workflows that take no input params.
NoopWorkflowIntrospectionSink: Default no-op sink for workflow step events.
PayloadCodec<T>: Encodes and decodes a strongly-typed payload value.
PayloadSigner: Handles signing and verification of envelope payloads.
PayloadVersionRegistry<T>: Registry of version-specific payload decoders for a single durable DTO type.
ProgressSignal: Signals a task progress update.
QueueBinding: Binding between a routing key (and optional headers) and a queue.
QueueBroker: Core queue operations required to publish and consume task deliveries.
QueueDefinition: Detailed queue definition with optional routing metadata.
QueuePriorityRange: Priority range constraint applied to a queue definition.
RateLimit: Typed rate-limit configuration shared across workers. Since: 0.3.0
RateLimitDecision: Result of attempting to acquire tokens from the rate limiter.
RateLimiter: Optional rate limiter interface shared across workers. Since: 0.1.0
ResultBackend: Result backend describes how task states are persisted and retrieved. Since: 0.1.0
RetryStrategy: Retry strategy used to compute the next backoff delay. Since: 0.1.0
RevokeStoreFactory: Factory for building RevokeStore instances.
RouteDefinition: Declarative routing rule mapping match criteria to targets.
RouteMatch: Routing match criteria with optional task glob, headers, or queue override.
RouteTarget: Route target describing queue or broadcast destination.
RoutingConfig: Canonical representation of routing configuration loaded from YAML or JSON.
RoutingSubscription: Subscription describing the queues and broadcast channels a worker should consume from.
RunState: Snapshot of a workflow run persisted by a WorkflowStore.
ScheduleEntry: Schedule entry persisted by a Beat-like scheduler.
ScheduleSpec: Base class for all scheduler specifications.
ScheduleSpecKind: Enumerates supported scheduler specification kinds.
ScheduleStore: Storage abstraction used by the scheduler to fetch due entries. Since: 0.1.0
ScheduleStoreFactory: Factory for building ScheduleStore instances.
ScheduleTimezoneResolver: Lazily resolves timezone identifiers.
SigningConfig: Configuration describing signing keys and behaviour.
SolarScheduleSpec: Schedule specification based on celestial/solar events.
StartWorkflowRequest: Workflow start request payload for isolate communication.
StartWorkflowResponse: Response payload for isolate workflow start requests.
StartWorkflowSignal: Request to start a workflow from an isolate.
Stem: Facade used by producer applications to enqueue tasks.
StemApp: Convenience bootstrap for setting up a Stem runtime with sensible defaults.
StemBackendFactory: Factory for building ResultBackend instances.
StemBrokerFactory: Factory for building QueueBroker instances.
StemClient: Shared entrypoint that owns broker/backend configuration for Stem runtimes.
StemMemoryAdapter: Built-in adapter for in-memory stores using the memory:// scheme.
StemModule: Generated or hand-authored bundle of tasks and workflow definitions.
StemObserver: Observer-only task result surface.
StemProducer: Producer-only task enqueue surface.
StemResourceFactory<T>: Wrapper for constructing and disposing Stem resources lazily.
StemStack: Resolved factories for a Stem deployment stack.
StemStoreAdapter: Adapter that can resolve Stem store factories from a URL.
StemStoreOverrides: Optional URL overrides for specific store kinds.
StemTaskApp: Convenience bootstrap for setting up a Stem runtime with sensible defaults.
StemWorkerConfig: Worker configuration used by the bootstrap helpers.
StemWorkerHost: Worker lifecycle surface for a managed application runtime.
StemWorkflowApp: Helper that bootstraps a workflow runtime on top of StemApp.
SystemWorkflowClock: Default clock that proxies to DateTime.now.
TaskCall<TArgs, TResult>: Represents a pending enqueue operation built from a TaskDefinition.
TaskCancellationToken: Cooperative cancellation state exposed to task code.
TaskChainResult<T extends Object?>: Result returned by Canvas.chain.
TaskContext: Context passed to handler implementations during execution.
TaskDefinition<TArgs, TResult>: Declarative task definition to build typed enqueue calls.
TaskDefn: Declares a function-backed task definition.
TaskEnqueueOptions: Options that apply only to the enqueue operation.
TaskEnqueueRequest: Enqueue request payload for isolate communication.
TaskEnqueueResponse: Response payload for isolate enqueue requests.
TaskEnqueueScope: Provides ambient metadata for task enqueue operations.
TaskError: Error metadata captured for failures.
TaskExecutionContext: Shared execution surface for task handlers and isolate entrypoints.
TaskExecutionModeProvider: Optional provider for handlers that explicitly declare their execution mode.
TaskInvocationContext: Context exposed to task entrypoints regardless of execution environment.
TaskInvocationSignal: Control messages emitted by task entrypoints running inside isolates.
TaskMetadata: Optional task metadata for documentation and tooling.
TaskObserver: Observation surface for task and group lifecycle state.
TaskOptions: Configuration options attached to task handlers.
TaskResult<T extends Object?>: Typed view over a TaskStatus returned by helpers such as Stem.waitForTask or canvas typed operations.
TaskResultCaller: Shared typed task-dispatch surface used by producers, apps, and contexts.
TaskRetryPolicy: Retry policy configuration for tasks and publish attempts.
TaskSignature<T extends Object?>: Describes a task to schedule along with optional decoder metadata.
TaskStatus: Canonical task record stored in the result backend.
TaskStatusListRequest: Query parameters used to list task status records.
TaskStatusPage: Paginated page of task status records.
TaskStatusRecord: Immutable record representing a persisted task status with timestamps.
TypedCanvasChain<TInput, TCurrent extends Object?>: A fluent, heterogeneous typed Canvas chain.
TypedTaskHandler<TArgs, TResult>: Typed task handler for the recommended manual registration path.
WaitForWorkflowRequest: Workflow wait request payload for isolate communication.
WaitForWorkflowResponse: Response payload for isolate workflow wait requests.
WaitForWorkflowSignal: Request to wait for a workflow from an isolate.
Worker: Worker runtime that consumes tasks from a broker and executes handlers.
WorkerAutoscaleConfig: Autoscaling configuration for worker concurrency.
WorkerEvent: An event emitted during worker operation.
WorkerLifecycleConfig: Lifecycle guard configuration for worker isolates and shutdown semantics.
WorkflowAnnotations: Collection of workflow-related annotations.
WorkflowCaller: Shared typed workflow-start surface used by apps, runtimes, and contexts.
WorkflowCancellationPolicy: Controls how the workflow runtime auto-cancels runs.
WorkflowCheckpoint: Declared script checkpoint metadata used for tooling and replay boundaries.
WorkflowCheckpointView: Uniform workflow checkpoint view for dashboard/CLI drilldowns.
WorkflowClock: Abstraction over time sources used by the workflow runtime and stores.
WorkflowDefinition<T extends Object?>: Declarative workflow definition built via FlowBuilder or a higher-level script facade. Flow definitions capture an ordered execution plan. Script definitions capture a script body plus optional checkpoint metadata used for introspection and tooling.
WorkflowDefn: Declares a workflow definition class.
WorkflowEdge: Describes a directed edge between workflow steps.
WorkflowEventBusFactory: Factory for building workflow EventBus instances that depend on a store.
WorkflowEventEmitter: Shared typed workflow-event dispatch surface used by apps and runtimes.
WorkflowEventRef<T>: Typed reference to a workflow resume event topic.
WorkflowExecutionContext: Shared execution context surface for flow steps and script checkpoints.
WorkflowManifestCheckpoint: Immutable manifest entry describing a declared script checkpoint.
WorkflowManifestEntry: Immutable manifest entry describing a workflow definition.
WorkflowManifestFlowStep: Immutable manifest entry describing a declared flow step.
WorkflowRef<TParams, TResult extends Object?>: Typed producer-facing reference to a registered workflow.
WorkflowRegistry: Registry for workflow definitions keyed by name.
WorkflowResult<T extends Object?>: Typed result returned by StemWorkflowApp.waitForCompletion.
WorkflowResumeContext: Shared suspension/resume surface implemented by flow steps and script checkpoints.
WorkflowRun: Marks a workflow class method as the run entrypoint.
WorkflowRunDetailView: Combined run + checkpoint drilldown view.
WorkflowRunRuntimeMetadata: Run-scoped runtime metadata persisted alongside workflow params.
WorkflowRuntime: Coordinates execution of workflow runs by dequeuing tasks, invoking steps, and persisting progress via a WorkflowStore.
WorkflowRuntimeEvent: Runtime orchestration event emitted by the workflow runtime.
WorkflowRunView: Uniform workflow run view tailored for dashboard/CLI drilldowns.
WorkflowScript<T extends Object?>: High-level workflow facade that allows scripts to be authored as a single async function using step, sleep, and awaitEvent helpers.
WorkflowScriptContext: Runtime context exposed to workflow scripts. Implementations are provided by the workflow runtime so scripts can execute with durable semantics.
WorkflowScriptStepContext: Context provided to each script checkpoint invocation. Mirrors FlowContext but tailored for the facade helpers.
WorkflowStartCall<TParams, TResult extends Object?>: Typed start request built from a WorkflowRef.
WorkflowStep: Marks a workflow class method as a durable step.
WorkflowStepEntry: Persisted step checkpoint metadata for a workflow run.
WorkflowStepEvent: Step-level execution event emitted by the workflow runtime.
WorkflowStore: Persistent storage for workflow runs, checkpoints, and suspensions.
WorkflowStoreFactory: Factory for building WorkflowStore instances.
WorkflowWatcher: Describes a workflow event watcher registered by the runtime.
WorkflowWatcherResolution: Represents a watcher that has been resolved (event delivered or timed out).

Enums

BatchLifecycleState: Lifecycle states for first-class batch submissions.
BrokerDeliveryGuarantee: Delivery guarantee advertised by a broker adapter.
FlowControlType: Enumerates the suspension control types.
RateLimiterFailureMode: Defines behavior when a limiter backend call fails.
SigningAlgorithm: Supported signing algorithms.
StemStoreKind: Store categories that can be resolved by adapters.
TaskExecutionMode: Selects the isolate in which a task handler executes.
TaskState: Logical task status across enqueue, running, success, failure states.
WorkerEventType: Types of events a worker can emit.
WorkerShutdownMode: Shutdown modes for workers.
WorkflowChannelKind: Logical channel used by workflow-related task enqueues.
WorkflowContinuationReason: Why a workflow continuation task was enqueued.
WorkflowDefinitionKind: Identifies whether a workflow is step-based or script-based.
WorkflowKind: Workflow definition type for annotated definitions.
WorkflowRuntimeEventType: Runtime-level workflow events emitted by orchestration transitions.
WorkflowStatus: Lifecycle state of a workflow run.
WorkflowStepEventType: Enumerates workflow step event types emitted by the runtime.
WorkflowStepKind: Kinds of workflow steps exposed for introspection.

Mixins

WorkflowIntrospectionSink: Sink for workflow step execution events.

Extensions

BrokerCapabilitiesExtension on Broker: Resolves capabilities without making Broker implementations add a new required member. External adapters therefore remain source-compatible and still receive a useful snapshot from the legacy getters.
LockFencingTokenX on Lock: Provides the fencing token when a lock implementation supports fencing.
NoArgsTaskDefinitionExtension on NoArgsTaskDefinition<TResult>: Convenience helpers for waiting on typed no-arg task definitions.
PayloadMapX on Map<String, Object?>: Typed read helpers for durable task-argument and workflow-parameter maps.
QueueBrokerCapabilitiesExtension on QueueBroker: Resolves capabilities for code that accepts the narrow QueueBroker type.
QueueBrokerOptionalOperations on QueueBroker: Optional operations for code that accepts the narrow QueueBroker type.
StemAppWorkflowExtension on StemApp: Convenience helpers for layering workflows onto an existing StemApp.
StemStackClientBootstrap on StemStack: Convenience helpers for bootstrapping clients from a resolved StemStack.
TaskDefinitionCanvasX on TaskDefinition<TArgs, TResult>: Convenience helpers for turning TaskDefinitions into signatures.
TaskDefinitionExtension on TaskDefinition<TArgs, TResult>: Convenience helpers for waiting on typed task definitions.
TaskExecutionContextProgressX on TaskExecutionContext: Shared task-progress helpers for execution contexts.
TaskHandlerExecutionModeX on TaskHandler<R>: Resolves the execution mode for a legacy or explicitly-declared handler.
TaskStateX on TaskState: Helpers for reasoning about task lifecycle states.
WorkflowEventRefExtension on WorkflowEventRef<T>: Convenience helpers for dispatching typed workflow events.
WorkflowEventRefWaitExtension on WorkflowEventRef<T>: Direct typed wait helpers on WorkflowEventRef.
WorkflowExecutionContextParams on WorkflowExecutionContext: Typed read helpers for workflow start parameters.
WorkflowExecutionContextValues on WorkflowExecutionContext: Typed read helpers for prior workflow step and checkpoint values.
WorkflowManifestDefinition on WorkflowDefinition<Object?>: Converts workflow definitions into typed manifest entries.
WorkflowRefExtension on WorkflowRef<TParams, TResult>: Convenience helpers for waiting on typed workflow refs using a generic WorkflowCaller.
WorkflowResumeContextValues on WorkflowResumeContext: Typed resume helpers for durable workflow suspensions.
WorkflowScriptContextParams on WorkflowScriptContext: Typed read helpers for workflow start parameters in script run methods.
WorkflowScriptStepSuspensionJson on WorkflowScriptStepContext: Low-level suspension helpers for workflow script checkpoints.

Constants

signatureHeader → const String: Header storing the base64 encoded payload signature.
signatureKeyHeader → const String: Header storing the signing key identifier used to calculate the signature.
workflow → const WorkflowAnnotations: Annotation namespace for workflow metadata.
workflowParentRunIdParamKey → const String: Reserved params key storing the parent workflow run identifier.
workflowRunTaskName → const String: Task name used for workflow run execution tasks.
workflowRuntimeMetadataParamKey → const String: Reserved params key storing internal runtime metadata for workflow runs.

Functions

registerModuleTaskHandlers(TaskRegistry registry, Iterable<TaskHandler<Object?>> handlers) → void: Registers task handlers while tolerating re-registration of identical handler instances.
task<T extends Object?>(String name, {Map<String, Object?> args = const {}, Map<String, String> headers = const {}, TaskOptions options = const TaskOptions(), Map<String, Object?> meta = const {}, DateTime? notBefore, T decode(Object? payload)?}) → TaskSignature<T>: Returns a TaskSignature that creates an Envelope for a task.

Typedefs

TaskArgsDecoder<TArgs> = TArgs Function(Map<String, Object?> args): Decodes persisted task arguments into the typed handler input.
TaskEntrypoint = FutureOr<Object?> Function(TaskInvocationContext context, Map<String, Object?> args): Signature for task entrypoints that can run inside isolate executors.
TaskMetaBuilder<TArgs> = Map<String, Object?> Function(TArgs args): Builds metadata for a task invocation using its arguments.
TaskResultDecoder<TResult> = TResult Function(Object? payload): Decodes a persisted task result payload into a typed value.
WorkflowScriptBody<T extends Object?> = FutureOr<T> Function(WorkflowScriptContext context): Declarative workflow definition built via FlowBuilder.

Exceptions / Errors

ScheduleConflictException: Thrown when a schedule mutation conflicts with a newer store version.
SignatureVerificationException: Thrown when an envelope signature is missing or invalid.
TaskCancellationException: Thrown when a task cooperatively observes cancellation.
TaskRetryRequest: Signals an explicit retry request from within a task handler.
TaskRevokedException: Exception thrown when a task is revoked during execution.
WorkflowSuspensionSignal: Internal control-flow signal used by expression-style suspension helpers.

Classes

Enums

Mixins

Extensions

Constants

Functions

Typedefs

Exceptions / Errors

stem package

stable library