portable library

Classes

AtomicTerminalResultBackend: Compatibility name for existing result backend implementations.
AtomicTerminalResultStore: Optional atomic terminal-state arbitration for result backends.
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.
ClockedScheduleSpec: Schedule specification for a fixed, absolute run time.
CodecTaskPayloadEncoder<T>: Bridges a typed Codec into the existing TaskPayloadEncoder contract.
ConsoleMetricsExporter: Simple exporter that prints JSON metrics to either sink or stdout.
CronScheduleSpec: Schedule specification for standard Cron expressions.
DartasticMetricsExporter: Metrics exporter that relays events through Dartastic's OTLP pipeline.
DartasticSdkMetricsExporter: Metrics exporter that uses an already configured Dartastic SDK provider.
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.
Delivery: Runtime wrapper containing the envelope plus broker-specific receipt info.
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.
Envelope: Task payload persisted inside a broker. Since: 0.1.0
ExponentialJitterRetryStrategy: Exponential backoff with jitter, capped at a configurable duration.
ExtendLeaseSignal: Signals a request to extend a task lease.
FencedLock: A lock handle that carries a monotonically increasing fencing token.
FunctionTaskHandler<R>: Convenience task handler that delegates execution to a top-level function suitable for isolate execution. Set runInIsolate to false or use FunctionTaskHandler.inline to keep execution in the worker isolate.
GroupDescriptor: Descriptor for group (e.g., chord) aggregation.
GroupResultStore: Persistence capability for task groups and chord arbitration.
GroupStatus: Aggregated status for a group/chord.
HeartbeatSignal: Signals a heartbeat from an executing task.
InMemoryTaskRegistry: Default in-memory registry implementation.
InspectableBroker: Optional broker capability for queue-depth inspection.
IntervalScheduleSpec: Schedule specification for fixed time intervals.
JsonTaskPayloadEncoder: Default encoder that stores payloads verbatim as JSON-friendly values.
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
MetricEvent: Immutable metric event emitted to exporters.
MetricsExporter: Consumers implement exporters to relay metric events to specific sinks.
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.
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.
PrometheusMetricsExporter: Exporter that accumulates metrics into Prometheus exposition format.
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 compatibility facade combining optional store capabilities. Since: 0.1.0
RetryStrategy: Retry strategy used to compute the next backoff delay. Since: 0.1.0
RouteDecision: Describes the routing decision for an enqueue request.
RouteDefinition: Declarative routing rule mapping match criteria to targets.
RouteMatch: Routing match criteria with optional task glob, headers, or queue override.
RouteRequest: Immutable request used when resolving routing decisions.
RouteTarget: Route target describing queue or broadcast destination.
RoutingConfig: Canonical representation of routing configuration loaded from YAML or JSON.
RoutingInfo: Routing metadata that accompanies published envelopes.
RoutingRegistry: Registry that resolves routing configuration into queue/broadcast decisions.
RoutingSubscription: Subscription describing the queues and broadcast channels a worker should consume from.
ScheduleCalculator: Computes the next run time for schedule entries.
ScheduleEntry: Schedule entry persisted by a Beat-like scheduler.
ScheduleRunner: Dispatches due ScheduleEntry records without starting a daemon.
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
ScheduleTimezoneResolver: Lazily resolves timezone identifiers.
SigningConfig: Configuration describing signing keys and behaviour.
SolarCalculator: Computes solar events (sunrise, sunset, solar noon) using NOAA SPA approximations.
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.
StemMetrics: Central registry that aggregates metrics before exporting them.
StemObserver: Observer-only task result surface.
StemProducer: Producer-only task enqueue surface.
TaskCall<TArgs, TResult>: Represents a pending enqueue operation built from a TaskDefinition.
TaskCancellationToken: Cooperative cancellation state exposed to task code.
TaskContext: Context passed to handler implementations during execution.
TaskDefinition<TArgs, TResult>: Declarative task definition to build typed enqueue calls.
TaskEnqueueOptions: Options that apply only to the enqueue operation.
TaskEnqueuer: Interface implemented by enqueuers like Stem and task contexts.
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.
TaskExecutionControl: Runtime callbacks and optional services exposed to an executing task.
TaskExecutionModeProvider: Optional provider for handlers that explicitly declare their execution mode.
TaskHandler<R>: Runtime task handler. Since: 0.1.0
TaskInputContext: Shared input surface for task execution contexts that retain invocation args.
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.
TaskPayloadEncoder: Transforms task handler results to and from backend-friendly payloads.
TaskPayloadEncoderRegistry: Registry for managing and resolving TaskPayloadEncoder instances.
TaskProcessCancelled: Task cancelled or expired.
TaskProcessFailure: Terminal handler failure after retry policy evaluation.
TaskProcessor: Processes a single envelope without owning broker delivery lifecycle.
TaskProcessOutcome: Semantic result of processing one task envelope.
TaskProcessRejected: Envelope rejected before handler execution.
TaskProcessRetry: Handler execution that should be attempted again later.
TaskProcessSkipped: Duplicate delivery skipped because a terminal status already exists.
TaskProcessSuccess: Successful handler execution.
TaskPublisher: Minimal transport contract used by producers and one-shot schedulers.
TaskPublisherLifecycle: Optional lifecycle capability for publishers that own disposable resources such as sockets or connection pools.
TaskRegistrationEvent: Event emitted when a task handler registers with a registry.
TaskRegistry: Registry mapping task names to handler implementations.
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.
TaskRetryVeto: Marker for errors whose own durable retry budget has already been exhausted.
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.
TaskStatusStore: Portable task-status persistence capability.
TaskTerminalFailureHandler: Optional durable failure finalization for a TaskHandler.
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.
WorkerHeartbeatStore: Persistence capability for worker heartbeat state.

Enums

BrokerDeliveryGuarantee: Delivery guarantee advertised by a broker adapter.
MetricType: Known metric aggregation types supported by the exporters.
RateLimiterFailureMode: Defines behavior when a limiter backend call fails.
RouteDecisionType: Distinguishes queue vs broadcast routing decisions.
RoutingTargetType: Target classification for routing operations.
SigningAlgorithm: Supported signing algorithms.
SolarEvent: Supported solar events for scheduling.
TaskCancellationReason: Reason task processing was cancelled without executing to success.
TaskExecutionMode: Selects the isolate in which a task handler executes.
TaskRecoveryPolicy: Recovery action when a delivery still has a running status for its attempt.
TaskRejectionReason: Reason a task envelope was rejected before handler execution.
TaskState: Logical task status across enqueue, running, success, failure states.

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.
PayloadCodecErasedDispatch on Codec<T, Object?>: Adapts standard codecs to Stem's erased, nullable payload boundaries.
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.
TaskDefinitionExtension on TaskDefinition<TArgs, TResult>: Convenience helpers for waiting on typed task definitions.
TaskEnqueuerBuilderExtension on TaskEnqueuer: Convenience helpers for building typed enqueue requests directly from a task enqueuer.
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.
TaskInputContextArgs on TaskInputContext: Typed read helpers for task invocation args.
TaskStateX on TaskState: Helpers for reasoning about task lifecycle states.

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.
stemArgsEncoderHeader → const String: Header key storing the args encoder identifier.
stemArgsEncoderMetaKey → const String: Metadata key storing the args encoder identifier.
stemResultEncoderMetaKey → const String: Metadata key storing the result encoder identifier.

Functions

ensureTaskPayloadEncoderRegistry(TaskPayloadEncoderRegistry? registry, {TaskPayloadEncoder resultEncoder = const JsonTaskPayloadEncoder(), TaskPayloadEncoder argsEncoder = const JsonTaskPayloadEncoder(), Iterable<TaskPayloadEncoder> additionalEncoders = const []}) → TaskPayloadEncoderRegistry: Ensures a TaskPayloadEncoderRegistry is available, instantiating one when registry is null and registering any additionalEncoders with whichever registry is ultimately used.
generateEnvelopeId() → String: Unique identifier generator used for task envelopes by default.

Typedefs

TaskArgsDecoder<TArgs> = TArgs Function(Map<String, Object?> args): Decodes persisted task arguments into the typed handler input.
TaskArgsEncoder<TArgs> = Map<String, Object?> Function(TArgs args): Encodes strongly typed task arguments into a JSON-ready map.
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.

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.
TaskInterruptedException: Evidence that earlier execution may have been interrupted or lost its lease.
TaskRetryRequest: Signals an explicit retry request from within a task handler.

Classes

Enums

Extensions

Constants

Functions

Typedefs

Exceptions / Errors

stem package

portable library