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Events reference

Events are created by the Temporal Cluster in response to external occurrences and Commands generated by a Workflow Execution. All possible Events that could appear in a Workflow Execution Event History are listed below.

WorkflowExecutionStarted

This is always the first Event in a Workflow Execution History. It indicates that the execution was invoked.

FieldDescription
workflow_typeThe name/type of Workflow that was initiated.
parent_workflow_namespaceThe namespace of the parent Workflow, if applicable.
parent_workflow_executionIdentifies the parent Workflow and the execution run.
parent_initiated_event_idId of the StartWorkflowExecutionInitiated Event this Event corresponds to.
task_queueThe Task Queue that this Workflow Task was enqueued in.
inputInformation that is deserialized by the SDK to provide arguments to the Workflow.
workflow_execution_timeoutThe total timeout period for a Workflow Execution, including retries and continue-as-new.
workflow_run_timeoutTimeout of a single Workflow run.
workflow_task_timeoutTimeout of a single Workflow Task.
continued_execution_run_idRun id of the previous Workflow which continued-as-new, retried or was executed by cron into this Workflow.
initiatorAllows the Workflow to continue as a new execution.
continued_failureSerialized result of a failure.
last_completion_resultInformation from the previously completed Task, if applicable.
original_execution_run_idThe Run Id of the original Workflow started.
identityId of the Worker that requested the start of this Workflow.
first_execution_run_idThe first run Id, along the chain of ContinueAsNew and Reset.
retry_policyThe amount of retries as determined by the service's dynamic configuration. Retries will happen until 'schedule_to_close_timeout' is reached.
attemptThe number of attempts that have been made to complete this Task.
workflow_execution_expiration_timeThe absolute time at which the Workflow will be timed out.
cron_scheduleDisplays the Workflow's cron schedule, if applicable.
first_workflow_task_backoffContains the amount of time between when this iteration of the Workflow was scheduled, and when it should run next. Applies to cron scheduling.
memoNon-indexed information to show in the Workflow.
search_attributesProvides data for setting up a Workflow's search attributes.
prev_auto_reset_points
headerInformation passed by the sender of the Signal that is copied into the Workflow Task.

WorkflowExecutionCompleted

This indicates that the Workflow Execution has successfully completed. The Event contains Workflow Execution results.

FieldDescription
resultSerialized result of completed Workflow.
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
new_execution_run_idThe Run Id of the new Workflow started by cron.

WorkflowExecutionFailed

This Event indicates that the Workflow Execution has unsuccessfully completed and contains the Workflow Execution error.

FieldDescription
failureSerialized result of a Workflow failure.
retry_stateThe reason provided for whether the Task should or shouldn't be retried.
workflow_task_completed_event_idThe Run Id of the WorkflowTaskCompleted that the Event was reported with.
new_execution_run_idThe Run Id of the new Workflow started by cron or Retry.

WorkflowExecutionTimedOut

This Event type indicates that the Workflow Execution has timed out by the Temporal Server due to the Workflow having not been completed within timeout settings.

FieldDescription
retry_stateThe reason provided for whether the Task should or shouldn't be retried.
new_execution_run_idThe Run Id of the new Workflow started by cron or Retry.

WorkflowExecutionCancelRequested

This Event type indicates that a request has been made to cancel the Workflow Execution.

FieldDescription
causeThe user-provided reason for the cancelation request.
external_initiated_event_idThe Run Id of the Event in the Workflow that requested cancelation, if applicable.
external_workflow_executionIdentifies the external Workflow and the run of the its execution.
identityId of the Worker that requested cancelation.

WorkflowExecutionCanceled

This Event type indicates that the client has confirmed the cancelation request and the Workflow Execution has been canceled.

FieldDescription
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
detailsAdditional information reported by the Workflow upon cancelation.

WorkflowExecutionSignaled

This Event type indicates the Workflow has received a Signal Event. The Event type contains the Signal name, as well as a Signal payload.

FieldDescription
signal_nameThe name/type of Signal to be fired.
inputInformation that is deserialized by the SDK to provide arguments to the Workflow function.
identityIdentifies the Worker that signaled to the Workflow.
headerInformation passed by the sender of the Signal that is copied into the Workflow Task.

WorkflowExecutionTerminated

This Event type indicates that the Workflow Execution has been forcefully terminated and that likely the terminate Workflow API was called.

FieldDescription
reasonInformation provided by the user or client for Workflow termination.
detailsAdditional information reported by the Workflow upon termination.
identityIdentifies the Worker that requested termination.

WorkflowExecutionContinuedAsNew

This Event type indicates that the Workflow has successfully completed, and a new Workflow has been started within the same transaction. This Event type contains last Workflow Execution results as well as new Workflow Execution inputs.

FieldDescription
new_execution_run_idThe Run Id of the new Workflow started by this Continue-As-New Event.
workflow_typeThe name/type of Workflow that was started by this Event.
task_queueThe Task Queue that this Workflow Task was enqueued in.
inputInformation that is deserialized by the SDK to provide arguments to the Workflow.
workflow_run_timeoutTimeout of a single Workflow run.
workflow_task_timeoutTimeout of a single Workflow task.
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event command was reported with.
backoff_start_intervalThe amount of time to delay the beginning of the ContinuedAsNew Workflow.
initiatorAllows the Workflow to continue as a new execution.
last_completion_resultInformation passed by the previously completed Task to the ongoing execution.
headerInformation passed by the sender of the Signal that is copied into the Workflow Task.
memoNon-indexed information to show in the Workflow.
search_attributesProvides data for setting up a Workflow's search attributes.

WorkflowTaskScheduled

This Event type indicates that the Workflow Task has been scheduled. The SDK client should now be able to process any new history events.

FieldDescription
task_queueThe Task Queuethat this Workflow Task was enqueued in.
start_to_close_timeoutThe time that the Worker takes to process this Task once it's received.
attemptThe number of attempts that have been made to complete this Task.

WorkflowTaskStarted

This Event type indicates that the Workflow Task has started. The SDK client has picked up the Workflow Task and is processing new history events.

FieldDescription
scheduled_event_idThe Id of the WorkflowTaskScheduled Event that this Workflow Task corresponds to.
identityIdentifies the Worker that started this Task.
request_idIdentifies the Workflow Task request.

WorkflowTaskCompleted

This Event type indicates that the Workflow Task completed.

FieldDescription
scheduled_event_idThe Id of the WorkflowTaskScheduled Event that this Workflow Task corresponds to.
started_event_idThe Id of the WorkflowTaskStarted Event that this Task corresponds to.
identityIdentity of the Worker that completed this Task.
binary_checksumBinary Id of the Worker that completed this Task.

The SDK client picked up the Workflow Task, processed new history events, and may or may not ask the Temporal Server to do additional work. It is possible for the following events to still occur:

WorkflowTaskTimedOut

This Event type indicates that the Workflow Task encountered a timeout. Either an SDK client with a local cache was not available at the time, or it took too long for the SDK client to process the task.

FieldDescription
scheduled_event_idThe Id of the WorkflowTaskScheduled Event that this Workflow Task corresponds to.
started_event_idThe Id of the WorkflowTaskStarted Event that this Task corresponds to.
timeout_typeThe type of timeout that has occurred.

WorkflowTaskFailed

This Event type indicates that the Workflow Task encountered a failure. Usually this means that the Workflow was non-deterministic. However, the Workflow reset functionality also uses this Event.

FieldDescription
scheduled_event_idThe Id of the WorkflowTaskScheduled Event that this Workflow Task corresponds to.
started_event_idThe Id of the WorkflowTaskStarted Event that this Workflow Task corresponds to.
failureDetails for the Workflow Task's failure.
identityThe identity of the Worker that failed this Task. The Worker must be explicitly defined to return a value for this field.
base_run_idThe original Run Id of the Workflow.
new_run_idThe Run Id of the reset Workflow.
fork_event_versionIdentifies the Event version that was forked off to the reset Workflow.
binary_checksumThe Binary Id of the Worker that failed this Task. The Worker must be explicitly defined to return a value for this field.

ActivityTaskScheduled

This Event type indicates that an Activity Task was scheduled. The SDK client should pick up this activity task and execute. This Event type contains activity inputs, as well as activity timeout configurations.

FieldDescription
activity_idThe identifier assigned to this Activity by a Worker or user.
activity_typeThe type of Activity that was scheduled.
namespaceNamespace of the Workflow that the Activity resides in.
task_queueThe Task Queue that this Activity Task was enqueued in.
headerInformation passed by the sender of the Signal that is copied into the Workflow Task.
inputInformation that is deserialized by the SDK to provide arguments to the Workflow function.
schedule_to_close_timeoutThe amount of time that a caller will wait for Activity completion. Limits the amount of time that retries will be attempted for this Activity.
schedule_to_start_timeoutLimits the time that an Activity Task can stay in a Task Queue. This timeout cannot be retried.
start_to_close_timeoutMaximum amount of execution time that an Activity is allowed after being picked up by a Worker. This timeout is retryable.
heartbeat_timeoutMaximum amount of time allowed between successful Worker heartbeats.
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
retry_policyThe amount of retries as determined by the service's dynamic configuration. Retries will happen until schedule_to_close_timeout is reached.

ActivityTaskStarted

This Event type indicates that the Activity Task has started executing. The SDK client has picked up the Activity Task and is processing the Activity invocation.

FieldDescription
scheduled_event_idThe Id of the ActivityTaskScheduled Event that this Task corresponds to.
identityIdentifies the Worker that started the Task.
request_idIdentifies the Activity Task request.
attemptThe number of attempts that have been made to complete this Task.
last_failureDetails from the most recent failure Event. Only assigned values if the Task has previously failed and been retried.

ActivityTaskCompleted

This Event type indicates that the Activity Task has completed. The SDK client has picked up and successfully completed the Activity Task. This Event type contains Activity execution results.

FieldDescription
resultSerialized result of a completed Activity.
scheduled_event_idThe Id of the ActivityTaskScheduled Event that this completion Event corresponds to.
started_event_idThe Id of the ActivityTaskStarted Event that this Task corresponds to.
identityIdentity of the Worker that completed this Task.

ActivityTaskFailed

This Event type indicates that the Activity Task has completed. The SDK picked up the Activity Task but unsuccessfully completed it. This Event type contains Activity execution errors.

FieldDescription
failureSerialized result of a Workflow failure.
scheduled_event_idThe Id of the ActivityTaskScheduled Event that this failure Event corresponds to.
started_event_idThe Id of the ActivityTaskStarted Event that this failure corresponds to.
retry_stateThe reason provided for whether the Task should or shouldn't be retried.

ActivityTaskTimedOut

This Event type indicates that the Activity has timed out according to the Temporal Server, due to the Activity having not completed within the timeout settings.

FieldDescription
failureSerialized result of a Workflow failure.
scheduled_event_idThe Id of the ActivityTaskScheduled Event that this timeout Event corresponds to.
started_event_idThe Id of the ActivityTaskStarted Event that this timeout corresponds to.
retry_stateThe reason provided for whether the Task should or shouldn't be retried.

ActivityTaskCancelRequested

This Event type indicates that a request to cancel the Activity has occurred. The SDK client will be able to confirm cancelation of an Activity during an Activity heartbeat.

FieldDescription
scheduled_event_idThe Id of the ActivityTaskScheduled Event that this cancel Event corresponds to.
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.

ActivityTaskCanceled

This Event type indicates that the Activity has been canceled.

FieldDescription
detailsAdditional information reported by the Activity upon confirming cancelation.
latest_cancel_requested_event_idId of the most recent ActivityTaskCancelRequested Event which refers to the same Activity.
scheduled_event_idThe Id of the ActivityTaskScheduled Event that this cancelation corresponds to.
started_event_idThe Id of the ActivityTaskStarted Event that this cancelation corresponds to.
identityIdentifies the Worker that requested cancelation.

TimerStarted

This Event type indicates a timer has started.

FieldDescription
timer_idThe Id assigned for the timer by a Worker or user.
start_to_fire_timeoutAmount of time to elapse before the timer fires.
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.

TimerFired

This Event type indicates a timer has fired.

FieldDescription
timer_idThe Id assigned for the timer by a Worker or user.
started_event_idThe Id of the TimerStarted Event itself.

TimerCanceled

This Event type indicates a Timer has been canceled.

FieldDescription
timer_idThe Id assigned for the timer by a Worker or user.
started_event_idThe Id of the TimerStarted Event itself.
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.

RequestCancelExternalWorkflowExecutionInitiated

This Event type indicates that a Workflow has requested that the Temporal Server try to cancel another Workflow.

FieldDescription
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
namespaceNamespace of the Workflow that`s going to be signaled for execution.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
child_workflow_onlySet to true if this Workflow is a child of the Workflow which issued the cancelation request.
reasonInformation provided by the user or client for Workflow cancelation.

RequestCancelExternalWorkflowExecutionFailed

This Event type indicates that Temporal Server could not cancel the targeted Workflow. This is usually because the target Workflow could not be found.

FieldDescription
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
namespaceNamespace of the Workflow that failed to cancel.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
initiated_event_idId of the [RequestCancelExternalWorkflowExecutionInitiated] Event this failure corresponds to.

ExternalWorkflowExecutionCancelRequested

This Event type indicates that the Temporal Server has successfully requested the cancelation of the target Workflow.

FieldDescription
initiated_event_idId of the RequestCancelExternalWorkflowExecutionInitiated Event that this cancelation request corresponds to.
namespaceNamespace of the Workflow that was requested tp cancel.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.

ExternalWorkflowExecutionSignaled

This Event type indicates that the Temporal Server has successfully Signaled the targeted Workflow.

FieldDescription
initiated_event_idId of the SignalExternalWorkflowExecutionInitiated Event this Event corresponds to.
namespaceNamespace of the Workflow that was signaled to.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.

MarkerRecorded

This Event type is transparent to the Temporal Server. The Server will only store it and will not try to understand it. The SDK client may use it for local activities or side effects.

FieldDescription
marker_nameIdentifies various markers.
detailsSerialized information recorded in the marker.
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
headerInformation passed by the sender of the Signal that is copied into the marker.
failureSerialized result of a Workflow failure.

StartChildWorkflowExecutionInitiated

This Event type indicates that the Temporal Server will try to start a child Workflow.

FieldDescription
namespaceNamespace of the child Workflow.
workflow_idIdentifies the child Workflow.
workflow_typeThe name/type of Workflow that was initiated.

StartChildWorkflowExecutionFailed

This Event type indicates a child Workflow Execution cannot be started / triggered. It is usually due to a child Workflow Id collision.

FieldDescription
namespaceNamespace of the child Workflow.
workflow_idIdentifies the child Workflow.
workflow_typeThe name/type of Workflow that has failed.
initiated_event_idId of the StartChildWorkflowExecutionInitiated Event this Event corresponds to.
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.

ChildWorkflowExecutionStarted

This Event type indicates a child Workflow Execution has successfully started / triggered. This would also cause the WorkflowExecutionStarted to be recorded for the Workflow that has started.

FieldDescription
namespaceNamespace of the child Workflow.
initiated_event_idId of the StartChildWorkflowExecutionInitiated Event this Event corresponds to.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
workflow_typeThe name/type of Workflow that has started execution.
headerInformation passed by the sender of the Signal that is copied into the child Workflow Task.

ChildWorkflowExecutionCompleted

This Event type indicates that the child Workflow Execution has successfully completed. This would also cause the WorkflowExecutionCompleted to be recorded for the Workflow that has completed.

FieldDescription
resultSerialized result of the completed child Workflow.
namespaceNamespace of the completed child Workflow.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
workflow_typeThe name/type of Workflow that was completed.
initiated_event_idId of the StartChildWorkflowExecutionInitiated Event this Event corresponds to.
started_event_idId of the ChildWorkflowExecutionStarted Event this Event corresponds to.

ChildWorkflowExecutionFailed

This Event type indicates that the child Workflow Execution has unsuccessfully completed. This would also cause the WorkflowExecutionFailed to be recorded for the Workflow that has failed.

FieldDescription
failureSerialized result of a Workflow failure.
namespaceNamespace of the child Workflow that failed.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
workflow_typeThe name/type of Workflow that has failed.
initiated_event_idId of the StartChildWorkflowExecutionInitiated Event this Event corresponds to.
started_event_idId of the ChildWorkflowExecutionStarted Event this failure corresponds to.
retry_stateThe reason provided for whether the Task should or shouldn't be retried.

ChildWorkflowExecutionCanceled

This Event type indicates that the child Workflow Execution has been canceled. This would also cause the WorkflowExecutionCanceled to be recorded for the Workflow that was canceled.

FieldDescription
detailsAdditional information reported by the child Workflow upon cancelation.
namespaceNamespace of the child Workflow that was canceled.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
workflow_typeThe name/type of Workflow that was canceled.
initiated_event_idId of the StartChildWorkflowExecutionInitiated Event this Event corresponds to.
started_event_idId of the ChildWorkflowExecutionStarted Event this cancelation corresponds to.

ChildWorkflowExecutionTimedOut

This Event type indicates that the child Workflow Execution has timed out by the Temporal Server. This would also cause the WorkflowExecutionTimeOut to be recorded for the Workflow that timed out.

FieldDescription
namespaceNamespace of the child Workflow.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
workflow_typeThe name/type of Workflow that has timed out.
initiated_event_idId of the StartChildWorkflowExecutionInitiated Event this Event corresponds to.
started_event_idId of the ChildWorkflowExecutionStarted Event that this timeout corresponds to.
retry_stateThe reason provided for whether the Task should or shouldn't be retried.

ChildWorkflowExecutionTerminated

This Event type indicates that the child Workflow Execution has been terminated. This would also cause the WorkflowExecutionTerminated to be recorded for the Workflow that was terminated.

FieldDescription
namespaceNamespace of the child Workflow.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
workflow_typeThe name/type of Workflow that was terminated.
initiated_event_idId of the StartChildWorkflowExecutionInitiated Event this Event corresponds to.
started_event_idId of the ChildWorkflowExecutionStarted Event that this termination corresponds to.
retry_stateThe reason provided for whether the Task should or shouldn't be retried.

SignalExternalWorkflowExecutionInitiated

This Event type indicates that the Temporal Server will try to Signal the targeted Workflow. This Event type contains the Signal name, as well as a Signal payload.

FieldDescription
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
namespaceNamespace of the Workflow that's to be signaled.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
signal_nameThe name/type of Signal to be fired.
inputInformation that is deserialized by the SDK to provide arguments to the Workflow function.
child_workflow_onlySet to true if this Workflow is a child of the Workflow which issued the cancelation request.
headerInformation to be passed from the Signal to the targeted Workflow.

SignalExternalWorkflowExecutionFailed

This Event type indicates that the Temporal Server cannot Signal the targeted Workflow, usually because the Workflow could not be found.

FieldDescription
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
namespaceNamespace of the Workflow that failed to execute.
workflow_executionIdentifies the Workflow and the run of the Workflow Execution.
initiated_event_idId of the RequestCancelExternalWorkflowExecutionInitiated Event this failure signal corresponds to.

UpsertWorkflowSearchAttributes

This Event type indicates that the Workflow Search Attributes should be updated and synchronized with the visibility store.

FieldDescription
workflow_task_completed_event_idThe Id of the WorkflowTaskCompleted that the Event was reported with.
search_attributesProvides data for setting up a Workflow`s search attributes.