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Failure detection - PHP SDK

Workflow timeouts​

Each Workflow timeout controls the maximum duration of a different aspect of a Workflow Execution.

Workflow timeouts are set when starting the Workflow Execution.

Create an instance of WorkflowOptions in the Client code and set your timeout.

Available timeouts are:

  • withWorkflowExecutionTimeout()
  • withWorkflowRunTimeout()
  • withWorkflowTaskTimeout()
$workflow = $this->workflowClient->newWorkflowStub(
    DynamicSleepWorkflowInterface::class,
    WorkflowOptions::new()
        ->withWorkflowId(DynamicSleepWorkflow::WORKFLOW_ID)
        ->withWorkflowIdReusePolicy(WorkflowIdReusePolicy::WORKFLOW_ID_REUSE_POLICY_ALLOW_DUPLICATE)
        // Set Workflow Timeout duration
        ->withWorkflowExecutionTimeout(CarbonInterval::minutes(2))
        // ->withWorkflowRunTimeout(CarbonInterval::minute(2))
        // ->withWorkflowTaskTimeout(CarbonInterval::minute(2))
);

Workflow retries​

A Retry Policy can work in cooperation with the timeouts to provide fine controls to optimize the execution experience.

Use a Retry Policy to retry a Workflow Execution in the event of a failure.

Workflow Executions do not retry by default, and Retry Policies should be used with Workflow Executions only in certain situations.

A Retry Policy can be configured with an instance of the RetryOptions object. To enable retries for a Workflow, you need to provide a Retry Policy object via ChildWorkflowOptions for Child Workflows or via WorkflowOptions for top-level Workflows.

$workflow = $this->workflowClient->newWorkflowStub(
      CronWorkflowInterface::class,
      WorkflowOptions::new()->withRetryOptions(
        RetryOptions::new()->withInitialInterval(120)
      )
);

How to set Activity timeouts​

Each Activity timeout controls the maximum duration of a different aspect of an Activity Execution.

The following timeouts are available in the Activity Options.

An Activity Execution must have either the Start-To-Close or the Schedule-To-Close Timeout set.

Because Activities are reentrant, only a single stub can be used for multiple Activity invocations.

Available timeouts are:

  • withScheduleToCloseTimeout()
  • withStartToCloseTimeout()
  • withScheduleToStartTimeout()
$this->greetingActivity = Workflow::newActivityStub(
    GreetingActivityInterface::class,
    // Set Activity Timeout duration
    ActivityOptions::new()
        ->withScheduleToCloseTimeout(CarbonInterval::seconds(2))
        // ->withStartToCloseTimeout(CarbonInterval::seconds(2))
        // ->withScheduleToStartTimeout(CarbonInterval::seconds(10))
);

How to set an Activity Retry Policy​

A Retry Policy works in cooperation with the timeouts to provide fine controls to optimize the execution experience.

Activity Executions are automatically associated with a default Retry Policy if a custom one is not provided.

To set an Activity Retry, set {@link RetryOptions} on {@link ActivityOptions}. The follow example creates a new Activity with the given options.

$this->greetingActivity = Workflow::newActivityStub(
    GreetingActivityInterface::class,
    ActivityOptions::new()
        ->withScheduleToCloseTimeout(CarbonInterval::seconds(10))
        ->withRetryOptions(
            RetryOptions::new()
                ->withInitialInterval(CarbonInterval::seconds(1))
                ->withMaximumAttempts(5)
                ->withNonRetryableExceptions([\InvalidArgumentException::class])
        )
);
}

For an executable code sample, see ActivityRetry sample in the PHP samples repository.

How to set the required Activity Timeouts​

Activity Execution semantics rely on several parameters. The only required value that needs to be set is either a Schedule-To-Close Timeout or a Start-To-Close Timeout. These values are set in the Activity Options.

How to Heartbeat an Activity​

An Activity Heartbeat is a ping from the Worker Process that is executing the Activity to the Temporal Service. Each Heartbeat informs the Temporal Service that the Activity Execution is making progress and the Worker has not crashed. If the Temporal Service does not receive a Heartbeat within a Heartbeat Timeout time period, the Activity will be considered failed and another Activity Task Execution may be scheduled according to the Retry Policy.

Heartbeats may not always be sent to the Temporal Service—they may be throttled by the Worker.

Activity Cancellations are delivered to Activities from the Temporal Service when they Heartbeat. Activities that don't Heartbeat can't receive a Cancellation. Heartbeat throttling may lead to Cancellation getting delivered later than expected.

Heartbeats can contain a details field describing the Activity's current progress. If an Activity gets retried, the Activity can access the details from the last Heartbeat that was sent to the Temporal Service.

Some Activities are long-running. To react to a crash quickly, use the Heartbeat mechanism, Activity::heartbeat(), which lets the Temporal Server know that the Activity is still alive. This acts as a periodic checkpoint mechanism for the progress of an Activity.

You can piggyback details on an Activity Heartbeat. If an Activity times out, the last value of details is included in the TimeoutFailure delivered to a Workflow. Then the Workflow can pass the details to the next Activity invocation. Additionally, you can access the details from within an Activity via Activity::getHeartbeatDetails. When an Activity is retried after a failure getHeartbeatDetails enables you to get the value from the last successful Heartbeat.

use Temporal\Activity;

class FileProcessingActivitiesImpl implements FileProcessingActivities
{
    // ...
    public function download(
        string $bucketName,
        string $remoteName,
        string $localName
    ): void
    {
        $this->dowloader->downloadWithProgress(
            $bucketName,
            $remoteName,
            $localName,
            // on progress
            function ($progress) {
                Activity::heartbeat($progress);
            }
        );

        Activity::heartbeat(100); // download complete

        // ...
    }

    // ...
}

How to set a Heartbeat Timeout​

A Heartbeat Timeout works in conjunction with Activity Heartbeats.

Some Activities are long-running. To react to a crash quickly, use the Heartbeat mechanism, Activity::heartbeat(), which lets the Temporal Server know that the Activity is still alive. This acts as a periodic checkpoint mechanism for the progress of an Activity.

You can piggyback details on an Activity Heartbeat. If an Activity times out, the last value of details is included in the TimeoutFailure delivered to a Workflow. Then the Workflow can pass the details to the next Activity invocation. Additionally, you can access the details from within an Activity via Activity::getHeartbeatDetails. When an Activity is retried after a failure getHeartbeatDetails enables you to get the value from the last successful Heartbeat.

use Temporal\Activity;

class FileProcessingActivitiesImpl implements FileProcessingActivities
{
    // ...
    public function download(
        string $bucketName,
        string $remoteName,
        string $localName
    ): void
    {
        $this->dowloader->downloadWithProgress(
            $bucketName,
            $remoteName,
            $localName,
            // on progress
            function ($progress) {
                Activity::heartbeat($progress);
            }
        );

        Activity::heartbeat(100); // download complete

        // ...
    }

    // ...
}