Error handling in PHP

An Activity, or a child Workflow, might fail, and you could handle errors differently based on the different error cases.

If the Activity returns throws an exception, that exception will be converted to Temporal\Exception\Failure\ApplicationFailure and wrapped inside Temporal\Exception\Failure\ActivityFailure or Temporal\Exception\Failure\ChildWorkflowFailure.

It is possible to throw ApplicationFailure manually with the ability to set nonRetryable flag.

There are other types of exceptions such as TimeoutFailure, CanceledFailure and ServerFailure.

All temporal related exceptions has suffix Failure for easier comprehension.

Here's an example of handling Activity errors within Workflow code that differentiates between different error types.

use Temporal\Exception\Failure;
use Temporal\Api\Enums\V1\TimeoutType;

$yourActivity = Workflow::newActivityStub(
    YourActivityInterface::class,
    ActivityOptions::new()->withScheduleToStartTimeout(60)
);

try {
    yield $yourActivity->doSomething();
} catch(Failure\ActivityFailure $e) {
    $cause = $e->getPrevious();

    if ($cause instanceof Failure\ApplicationFailure) {
        // domain code error
        $originalError = $cause->getType();
        $originalMessage = $cause->getOriginalMessage();

        // optional: additional error details
        $value = $cause->getDetails()->getValue(0, Type::TYPE_STRING);
    }

     if ($cause instanceof Failure\TimeoutFailure) {
        switch ($cause->getTimeoutType()) {
            case TimeoutType::TIMEOUT_TYPE_START_TO_CLOSE:
                // handle start to close timeout
                break;
            case TimeoutType::TIMEOUT_TYPE_SCHEDULE_TO_CLOSE:
                // handle schedule to close timeout
                break;
            case TimeoutType::TIMEOUT_TYPE_SCHEDULE_TO_START:
                // handle schedule to start timeout
                break;
            case TimeoutType::TIMEOUT_TYPE_HEARTBEAT:
                // handle heartbeat timeout

                // last recorded heartbeat (optional)
                $heartbeatDetails = $cause->getLastHeartbeatDetails();
                break;
        }
    }

    if($cause instanceof Failure\CanceledFailure){
        // activity was canceled
    }

    if ($cause instanceof Failure\ServerFailure) {
        // handle server error
    }
}