Enum Event 

pub enum Event {
    WorkflowStarted {
        envelope: EventEnvelope,
        workflow_type: String,
        input: Payload,
        run_id: RunId,
        parent_run_id: Option<RunId>,
        package_version: PackageVersion,
    },
    WorkflowCompleted {
        envelope: EventEnvelope,
        result: Payload,
    },
    WorkflowFailed {
        envelope: EventEnvelope,
        error: WorkflowError,
    },
    WorkflowCancelled {
        envelope: EventEnvelope,
        reason: String,
    },
    WorkflowTimedOut {
        envelope: EventEnvelope,
        timeout: String,
    },
    WorkflowContinuedAsNew {
        envelope: EventEnvelope,
        input: Payload,
        workflow_type: Option<String>,
        parent_run_id: RunId,
    },
    WorkflowReopened {
        envelope: EventEnvelope,
        run_id: RunId,
        reopened: Vec<ActivityId>,
    },
    WorkflowPaused {
        envelope: EventEnvelope,
        run_id: RunId,
        reason: Option<String>,
        operator: Option<String>,
    },
    WorkflowResumed {
        envelope: EventEnvelope,
        run_id: RunId,
        operator: Option<String>,
    },
    SearchAttributesUpdated {
        envelope: EventEnvelope,
        workflow_id: WorkflowId,
        attributes: HashMap<String, SearchAttributeValue>,
    },
    ActivityScheduled {
        envelope: EventEnvelope,
        activity_id: ActivityId,
        activity_type: String,
        input: Payload,
        task_queue: String,
        node: Option<String>,
    },
    ActivityStarted {
        envelope: EventEnvelope,
        activity_id: ActivityId,
        attempt: u32,
    },
    ActivityCompleted {
        envelope: EventEnvelope,
        activity_id: ActivityId,
        result: Payload,
        attempt: u32,
    },
    ActivityFailed {
        envelope: EventEnvelope,
        activity_id: ActivityId,
        error: ActivityError,
        attempt: u32,
    },
    ActivityCancelled {
        envelope: EventEnvelope,
        activity_id: ActivityId,
        attempt: u32,
    },
    TimerStarted {
        envelope: EventEnvelope,
        timer_id: TimerId,
        fire_at: DateTime<Utc>,
    },
    TimerFired {
        envelope: EventEnvelope,
        timer_id: TimerId,
    },
    TimerCancelled {
        envelope: EventEnvelope,
        timer_id: TimerId,
        cause: TimerCancelCause,
    },
    WithTimeoutCompleted {
        envelope: EventEnvelope,
        timer_id: TimerId,
        outcome: WithTimeoutOutcome,
        result: Option<Payload>,
    },
    SignalReceived {
        envelope: EventEnvelope,
        name: String,
        payload: Payload,
    },
    SignalSent {
        envelope: EventEnvelope,
        target_workflow_id: WorkflowId,
        name: String,
        payload: Payload,
    },
    ChildWorkflowStarted {
        envelope: EventEnvelope,
        child_workflow_id: WorkflowId,
        workflow_type: String,
        input: Payload,
        package_version: PackageVersion,
    },
    ChildWorkflowCompleted {
        envelope: EventEnvelope,
        child_workflow_id: WorkflowId,
        result: Payload,
    },
    ChildWorkflowFailed {
        envelope: EventEnvelope,
        child_workflow_id: WorkflowId,
        error: WorkflowError,
    },
    ChildWorkflowCancelled {
        envelope: EventEnvelope,
        child_workflow_id: WorkflowId,
    },
    ScheduleCreated {
        envelope: EventEnvelope,
        schedule_id: ScheduleId,
        config: ScheduleConfig,
    },
    ScheduleUpdated {
        envelope: EventEnvelope,
        schedule_id: ScheduleId,
        config: ScheduleConfig,
    },
    SchedulePaused {
        envelope: EventEnvelope,
        schedule_id: ScheduleId,
    },
    ScheduleResumed {
        envelope: EventEnvelope,
        schedule_id: ScheduleId,
    },
    ScheduleDeleted {
        envelope: EventEnvelope,
        schedule_id: ScheduleId,
    },
    ScheduleTriggered {
        envelope: EventEnvelope,
        schedule_id: ScheduleId,
        workflow_id: WorkflowId,
        run_id: RunId,
    },
}

A recorded workflow history event.

User data is carried as opaque Payload values, while failures use the closed workflow and activity error types from this crate.

Variants

WorkflowStarted

A workflow execution started with a type name and input payload.

Fields

envelope: EventEnvelope

Recording metadata for this event.

workflow_type: String

Workflow type selected by the caller.

input: Payload

Opaque workflow input payload.

run_id: RunId

Concrete run identifier started by this event.

parent_run_id: Option<RunId>

Parent run that continued as this run, when this start is part of a continue-as-new chain.

package_version: PackageVersion

Package version this run was resolved against at record time.

Recovery and replay resolve workflow code from this recorded version; they never re-resolve a “latest” version.

WorkflowCompleted

A workflow execution completed successfully; this terminal event projects to Completed.

Fields

envelope: EventEnvelope

Recording metadata for this event.

result: Payload

Opaque workflow result payload.

WorkflowFailed

A workflow execution failed terminally; this terminal event projects to Failed.

Fields

envelope: EventEnvelope

Recording metadata for this event.

error: WorkflowError

Terminal workflow failure.

WorkflowCancelled

A workflow execution was cancelled; this terminal event projects to Cancelled.

Fields

envelope: EventEnvelope

Recording metadata for this event.

reason: String

Human-readable cancellation reason.

WorkflowTimedOut

A workflow execution timed out; this terminal event projects to TimedOut.

Fields

envelope: EventEnvelope

Recording metadata for this event.

timeout: String

Descriptor identifying the timeout that elapsed.

Intentionally stringly-typed: the closed set of timeout kinds is defined by cluster AT (timers and signals), not by the core event model.

WorkflowContinuedAsNew

A workflow execution continued as a new run; this terminal event projects to ContinuedAsNew.

Fields

envelope: EventEnvelope

Recording metadata for this event.

input: Payload

Opaque workflow input payload carried into the new run.

workflow_type: Option<String>

Workflow type override for the new run, when migration changes the workflow type.

When absent, the new run uses the current workflow type.

parent_run_id: RunId

Run identifier for the current run that is being continued.

WorkflowReopened

A failed run was reopened.

Engine-internal — never authored by workflow or SDK code. This is the compensating event that reconciles reopen with the status-is-a-projection invariant: under the last-lifecycle-event-wins scan it supersedes the run’s prior terminal event and returns the run to Running, exactly as a replacement Event::WorkflowStarted does for continue-as-new. Terminal detection is scoped to “since the last reopen point”, so a run holds exactly one terminal event per lease.

Fields

envelope: EventEnvelope

Recording metadata for this event.

run_id: RunId

Run being reopened — the run that recorded the superseded terminal event and that the reopened execution continues.

reopened: Vec<ActivityId>

Activities to re-dispatch on replay: those that ended in a terminal failure in this run with no later successful attempt. The history cursor treats each as a reset point so the recorded failure is superseded and the activity resolves to live re-dispatch.

WorkflowPaused

A running workflow was paused by an operator.

Engine-internal — never authored by workflow or SDK code. A NON-terminal lifecycle marker: under the last-lifecycle-event-wins scan it projects the run to crate::WorkflowStatus::Paused, holding new activity dispatch at the outbox while every durable record path (timer fires, signal receipts, drained completions) keeps recording. It is invisible to the replay cursor (it is neither a terminal nor a run-start reset), so a paused-then-resumed history replays byte-identically to one that was never paused.

Fields

envelope: EventEnvelope

Recording metadata for this event.

run_id: RunId

Run being paused — the live, non-terminal run the operator held.

reason: Option<String>

Optional operator-supplied pause reason.

operator: Option<String>

Optional identity of the operator who issued the pause.

WorkflowResumed

A paused workflow was resumed by an operator.

Engine-internal — never authored by workflow or SDK code. Supersedes the run’s prior Event::WorkflowPaused under the last-lifecycle-event-wins scan, returning the run to crate::WorkflowStatus::Running, and — like Event::WorkflowPaused — is invisible to the replay cursor.

Fields

envelope: EventEnvelope

Recording metadata for this event.

run_id: RunId

Run being resumed.

operator: Option<String>

Optional identity of the operator who issued the resume.

SearchAttributesUpdated

Workflow search attributes were updated for visibility and query projection.

Fields

envelope: EventEnvelope

Recording metadata for this event.

workflow_id: WorkflowId

Workflow whose search attributes changed.

attributes: HashMap<String, SearchAttributeValue>

Updated search attributes keyed by attribute name.

ActivityScheduled

An activity was scheduled by workflow code.

Fields

envelope: EventEnvelope

Recording metadata for this event.

activity_id: ActivityId

Deterministic activity identifier derived from the scheduling sequence position.

activity_type: String

Activity type selected by workflow code.

input: Payload

Opaque activity input payload.

task_queue: String

Pool/flavour selector this activity dispatches to within the workflow’s namespace (NSTQ-3). This is the durable source-of-truth for re-targeting the same task queue on reopen/recovery, mirroring how the namespace is recovered from history but recorded per-activity rather than as a workflow-level search attribute.

Replay-safety: histories recorded before this field existed have no task_queue on their ActivityScheduled events. Decode defaults the missing value to DEFAULT_TASK_QUEUE ("default") via #[serde(default = ...)], so an old history deterministically re-derives task_queue = "default" — never panics, never differs run-to-run. The encoding of the existing fields is untouched.

node: Option<String>

OPTIONAL node affinity this activity dispatches to (NODE-3). None = no affinity (the genuine current value; SDK-level node selection is NODE-4). This is the durable source-of-truth for re-targeting the same node on reopen/recovery, recorded per-activity alongside task_queue.

Replay-safety: histories recorded before this field existed have no node key on their ActivityScheduled events. serde’s Option default is None, so #[serde(default)] decodes a missing node deterministically to None — never a sentinel, never panics, never differs run-to-run. The encoding of the existing fields is untouched.

ActivityStarted

An activity worker started executing an activity attempt.

Fields

envelope: EventEnvelope

Recording metadata for this event.

activity_id: ActivityId

Activity being executed.

attempt: u32

One-based activity attempt number this start belongs to (NOI-0).

Matches the attempt on the Event::ActivityFailed / Event::ActivityCompleted / Event::ActivityCancelled that terminates the SAME attempt, so (workflow, activity, attempt) is a stable identity across the whole lifecycle — the key the NOI dedupe/guard/session-id design is built on.

Replay-safety: histories recorded before this field existed have no attempt key on their ActivityStarted events. Decode defaults the missing value to [LEGACY_ACTIVITY_ATTEMPT] (0) via #[serde(default = ...)] — never panics, never differs run-to-run. Because real attempts are one-based, 0 is a distinguishable legacy/unknown sentinel, never a genuine attempt. The encoding of the existing fields is untouched.

ActivityCompleted

An activity completed successfully.

Fields

envelope: EventEnvelope

Recording metadata for this event.

activity_id: ActivityId

Activity that produced the result.

result: Payload

Opaque activity result payload.

attempt: u32

One-based activity attempt number that produced this completion (NOI-0).

Matches the attempt on the Event::ActivityStarted of the SAME attempt, so a completed activity carries one consistent attempt readable off both its start and its terminal — the negative-control invariant NOI-0 gates on.

Replay-safety: histories recorded before this field existed have no attempt key on their ActivityCompleted events. Decode defaults the missing value to [LEGACY_ACTIVITY_ATTEMPT] (0) via #[serde(default = ...)] — never panics, never differs run-to-run. The encoding of the existing fields is untouched.

ActivityFailed

An activity attempt failed.

The attempt field together with ActivityError’s retryable or terminal classification lets replay distinguish a retryable interim failure from a terminal one for the same ActivityId.

Fields

envelope: EventEnvelope

Recording metadata for this event.

activity_id: ActivityId

Activity whose attempt failed.

error: ActivityError

Classified activity failure.

attempt: u32

One-based activity attempt number that produced this failure.

ActivityCancelled

An activity was cancelled as an explicit cancellation outcome.

Fields

envelope: EventEnvelope

Recording metadata for this event.

activity_id: ActivityId

Activity that was cancelled.

attempt: u32

One-based activity attempt number that was cancelled (NOI-0).

Matches the attempt on the Event::ActivityStarted of the SAME attempt, so the cancellation terminal is attributable to a specific attempt exactly like Event::ActivityFailed is.

Replay-safety: histories recorded before this field existed have no attempt key on their ActivityCancelled events. Decode defaults the missing value to [LEGACY_ACTIVITY_ATTEMPT] (0) via #[serde(default = ...)] — never panics, never differs run-to-run. The encoding of the existing fields is untouched.

TimerStarted

A timer was scheduled to fire at a deterministic timestamp.

Fields

envelope: EventEnvelope

Recording metadata for this event.

timer_id: TimerId

Timer selected by workflow code or assigned by the engine.

fire_at: DateTime<Utc>

UTC timestamp at which the timer becomes eligible to fire.

TimerFired

A timer fired.

Fields

envelope: EventEnvelope

Recording metadata for this event.

timer_id: TimerId

Timer that fired.

TimerCancelled

A timer was cancelled as an explicit cancellation outcome.

Fields

envelope: EventEnvelope

Recording metadata for this event.

timer_id: TimerId

Timer that was cancelled.

cause: TimerCancelCause

Who retired the timer. Decides reopen behavior: a TimerCancelCause::CancelTeardown cancellation is re-armed when the run is reopened; a TimerCancelCause::WorkflowIntent cancellation is permanent.

Replay-safety: histories recorded before this field existed have no cause key. Decode defaults the missing value to TimerCancelCause::WorkflowIntent via #[serde(default)] — the pre-field behavior (never resurrected), never panics, never differs run-to-run. The encoding of the existing fields is untouched.

WithTimeoutCompleted

A with_timeout operation reached a durable terminal outcome.

Fields

envelope: EventEnvelope

Recording metadata for this event.

timer_id: TimerId

Timer that bounded the operation.

outcome: WithTimeoutOutcome

Recorded timeout outcome.

result: Option<Payload>

JSON-encoded BEAM term payload for completed operation results.

SignalReceived

A signal was delivered to the workflow.

Fields

envelope: EventEnvelope

Recording metadata for this event.

name: String

Signal name selected by the sender.

payload: Payload

Opaque signal payload.

SignalSent

A signal was sent by this workflow to another workflow.

Fields

envelope: EventEnvelope

Recording metadata for this event.

target_workflow_id: WorkflowId

Target workflow identifier selected by workflow code.

name: String

Signal name selected by workflow code.

payload: Payload

Opaque signal payload.

ChildWorkflowStarted

A child workflow was started.

Fields

envelope: EventEnvelope

Recording metadata for this event.

child_workflow_id: WorkflowId

Child workflow identifier.

workflow_type: String

Child workflow type selected by the parent.

input: Payload

Opaque child workflow input payload.

package_version: PackageVersion

Package version resolved for the child at record time.

The crash-repair sweep and the child’s own start use exactly this recorded version, so the crash path resolves identically to the crash-free path.

ChildWorkflowCompleted

A child workflow completed successfully.

Fields

envelope: EventEnvelope

Recording metadata for this event.

child_workflow_id: WorkflowId

Child workflow that produced the result.

result: Payload

Opaque child workflow result payload.

ChildWorkflowFailed

A child workflow failed terminally.

Fields

envelope: EventEnvelope

Recording metadata for this event.

child_workflow_id: WorkflowId

Child workflow that failed.

error: WorkflowError

Terminal child workflow failure.

ChildWorkflowCancelled

A child workflow was cancelled as an explicit cancellation outcome.

Fields

envelope: EventEnvelope

Recording metadata for this event.

child_workflow_id: WorkflowId

Child workflow that was cancelled.

ScheduleCreated

A schedule resource was created.

Fields

envelope: EventEnvelope

Recording metadata for this event.

schedule_id: ScheduleId

Schedule resource that was created.

config: ScheduleConfig

Persisted schedule configuration.

ScheduleUpdated

A schedule resource was updated.

Fields

envelope: EventEnvelope

Recording metadata for this event.

schedule_id: ScheduleId

Schedule resource that was updated.

config: ScheduleConfig

Updated schedule configuration.

SchedulePaused

A schedule resource was paused.

Fields

envelope: EventEnvelope

Recording metadata for this event.

schedule_id: ScheduleId

Schedule resource that was paused.

ScheduleResumed

A paused schedule resource was resumed.

Fields

envelope: EventEnvelope

Recording metadata for this event.

schedule_id: ScheduleId

Schedule resource that was resumed.

ScheduleDeleted

A schedule resource was deleted.

Fields

envelope: EventEnvelope

Recording metadata for this event.

schedule_id: ScheduleId

Schedule resource that was deleted.

ScheduleTriggered

A schedule tick started a workflow execution.

Fields

envelope: EventEnvelope

Recording metadata for this event.

schedule_id: ScheduleId

Schedule resource that fired.

workflow_id: WorkflowId

Workflow execution started by the schedule tick.

run_id: RunId

Run started by the schedule tick.

Implementations

impl Event

pub const fn envelope(&self) -> &EventEnvelope

Returns the envelope recorded with this event.

pub const fn seq(&self) -> u64

Returns the monotonic sequence number recorded for this event.

pub const fn recorded_at(&self) -> &DateTime<Utc>

Returns the deterministic recorded timestamp for this event.

pub const fn workflow_id(&self) -> &WorkflowId

Returns the workflow history that owns this event.

Trait Implementations

impl Clone for Event

fn clone(&self) -> Event

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Event

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Event

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Event

fn eq(&self, other: &Event) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for Event

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Event

impl TS for Event

type WithoutGenerics = Event

If this type does not have generic parameters, then WithoutGenerics should just be Self. If the type does have generic parameters, then all generic parameters must be replaced with a dummy type, e.g ts_rs::Dummy or ().
The only requirement for these dummy types is that EXPORT_TO must be None.

type OptionInnerType = Event

If the implementing type is std::option::Option<T>, then this associated type is set to T. All other implementations of TS should set this type to Self instead.

fn ident(cfg: &Config) -> String

Identifier of this type, excluding generic parameters.

fn docs() -> Option<String>

JSDoc comment to describe this type in TypeScript - when TS is derived, docs are automatically read from your doc comments or #[doc = ".."] attributes

fn name(cfg: &Config) -> String

Name of this type in TypeScript, including generic parameters

fn decl_concrete(cfg: &Config) -> String

Declaration of this type using the supplied generic arguments. The resulting TypeScript definition will not be generic. For that, see TS::decl(). If this type is not generic, then this function is equivalent to TS::decl().

fn decl(cfg: &Config) -> String

Declaration of this type, e.g. type User = { user_id: number, ... }. This function will panic if the type has no declaration.

fn inline(cfg: &Config) -> String

Formats this types definition in TypeScript, e.g { user_id: number }. This function will panic if the type cannot be inlined.

fn inline_flattened(cfg: &Config) -> String

Flatten a type declaration. This function will panic if the type cannot be flattened.

fn visit_generics(v: &mut impl TypeVisitor)

where Self: 'static,

Iterates over all type parameters of this type.

fn output_path() -> Option<PathBuf>

Returns the output path to where T should be exported, relative to the output directory. The returned path does not include any base directory.

fn visit_dependencies(v: &mut impl TypeVisitor)

where Self: 'static,

Iterates over all dependency of this type.

fn dependencies(cfg: &Config) -> Vec<Dependency>

where Self: 'static,

Resolves all dependencies of this type recursively.

fn export(cfg: &Config) -> Result<(), ExportError>

where Self: 'static,

Manually export this type to the filesystem. To export this type together with all of its dependencies, use TS::export_all.

fn export_all(cfg: &Config) -> Result<(), ExportError>

where Self: 'static,

Manually export this type to the filesystem, together with all of its dependencies. To export only this type, without its dependencies, use TS::export.

fn export_to_string(cfg: &Config) -> Result<String, ExportError>

where Self: 'static,

Manually generate bindings for this type, returning a String. This function does not format the output, even if the format feature is enabled.