Status tugas polling

Pembuatan File Data Terstruktur (SDF) dapat berlangsung dari beberapa detik hingga beberapa jam. Tugas selesai saat kolom done di Operation adalah True.

Operation diidentifikasi dengan nama berformat /sdfdownloadtasks/operations/{id}. Ambil Operation secara rutin dengan nama ini menggunakan sdfdownloadtasks.operations.get untuk melihat apakah tugas telah selesai. Proses ini dikenal sebagai "polling".

Jika done adalah True, kolom response atau error akan ditetapkan. Tugas yang gagal akan menetapkan kolom error. Objek Status yang ditetapkan memberikan detail tentang kegagalan. Tugas yang berhasil akan menetapkan kolom response. Download SDF yang dihasilkan dari response.resourceName.

Polling yang tidak efisien dapat menggunakan banyak kuota permintaan API. Batasi percobaan ulang dan hemat kuota menggunakan backoff eksponensial.

Berikut cara melakukan polling tugas download SDF menggunakan backoff eksponensial:

Java

// Provide the name of the sdfdownloadtask operation.
String operationName = operation-name;

// Configure the Operations.get request.
Sdfdownloadtasks.Operations.Get operationRequest =
    service.sdfdownloadtasks().operations().get(operationName);

// Configure exponential backoff for checking the status of our operation.
ExponentialBackOff backOff =
    new ExponentialBackOff.Builder()
        .setInitialIntervalMillis(5000) // setting initial interval to five seconds
        .setMaxIntervalMillis(5000 * 60) // setting max interval to five minutes
        .setMaxElapsedTimeMillis(5000 * 60 * 60) // setting max elapsed time to five hours
        .build();
long backoffMillis = 0;

// Create default operation variable.
Operation operation = new Operation();

do {
  // Sleep before retrieving operation again.
  Thread.sleep(backoffMillis);

  // Retrieve operation.
  operation = operationRequest.execute();

  // If operation is not done, calculate next sleep period.
  if (operation.getDone() == null) {
    backoffMillis = backOff.nextBackOffMillis();
    if (backoffMillis == ExponentialBackOff.STOP) {
      System.out.printf("The operation has taken more than five hours to complete.%n");
      break;
    }
    System.out.printf(
        "Operation %s is still running, sleeping for %s milliseconds.%n",
        operationName, backoffMillis);
  }
} while (operation.getDone() == null);

// Check whether operation finished with an error, or is completed and ready to download.
if (operation.getDone() != null) {
  if (operation.getError() != null) {
    System.out.printf(
        "The operation finished in error with code %s: %s%n",
        operation.getError().getCode(), operation.getError().getMessage());
  } else {
    System.out.printf(
        "The operation completed successfully. Resource %s was created.%n",
        operation.getResponse().get("resourceName").toString());
  }
}

Python

# Provide the name of the sdfdownloadtask operation.
operation_name = operation-name

# Set the following values that control retry behavior while the operation
# is running.
# Minimum amount of time between polling requests. Defaults to 5 seconds.
min_retry_interval = 5
# Maximum amount of time between polling requests. Defaults to 5 minutes.
max_retry_interval = 5 * 60
# Maximum amount of time to spend polling. Defaults to 5 hours.
max_retry_elapsed_time = 5 * 60 * 60

def next_sleep_interval(previous_sleep_interval):
  """Calculates the next sleep interval based on the previous."""
  min_interval = previous_sleep_interval or min_retry_interval
  max_interval = previous_sleep_interval * 3 or min_retry_interval
  return min(max_retry_interval, random.randint(min_interval, max_interval))

# Configure the sdfdownloadtasks.operations.get request.
get_request = service.sdfdownloadtasks().operations().get(name=operation_name)

sleep = 0
start_time = time.time()

while True:
  # Retrieve the operation.
  operation = get_request.execute()

  if "done" in operation:
    if "error" in operation:
      print(
          f"The operation finished in error with code "
          f'{operation["error"]["code"]}: {operation["error"]["message"]}'
      )
    else:
      print(
          f"The operation completed successfully. The resulting files can be "
          f'downloaded at {operation["response"]["resourceName"]}.'
      )
    break
  elif time.time() - start_time > max_retry_elapsed_time:
    print("SDF generation deadline exceeded.")
    break

  sleep = next_sleep_interval(sleep)
  print(
      f"Operation {operation_name} is still running, sleeping for "
      f"{sleep} seconds."
  )
  time.sleep(sleep)

PHP

// The following values control retry behavior while the task is processing.
// Minimum amount of time between polling requests. Defaults to 5 seconds.
$minRetryInterval = 5;
// Maximum amount of time between polling requests. Defaults to 5 minutes.
$maxRetryInterval = 300;
// Maximum amount of time to spend polling. Defaults to 5 hours.
$maxRetryElapsedTime = 18000;

// Provide the name of the sdfdownloadtask operation.
$operationName = operation-name;

// Poll operation.
$sleep = 0;
$startTime = time();
do {
    try {
        // Call the API, retrieving the SDF Download Task.
        $operation = $this->service->sdfdownloadtasks_operations->get(
            $operationName
        );
    } catch (\Exception $e) {
        $this->renderError($e);
        return;
    }

    // Check if retrieved operation is finished.
    if ($operation->getDone() === true) {
        if($operation->getError() !== null) {
            $error = $operation->getError();
            printf(
                'The operation finished in error with code %s: %s<br>',
                $error->setCode(),
                $error->setMessage()
            );
            break;
        } else {
            $response = $operation->getResponse();
            printf(
                'The operation completed successfully. Resource %s '
                    . 'was created.<br>',
                $response['resourceName']
            );
            break;
        }
    } elseif (time() - $startTime > self::MAX_RETRY_ELAPSED_TIME) {
        print '<p>SDF download task processing deadline exceeded</p>';
        break;
    }

    // Generate next sleep interval.
    $minInterval = max($minRetryInterval, $sleep);
    $maxInterval = max(
        $minRetryInterval,
        $sleep * 3
    );
    $sleep = min($maxRetryInterval, rand($minInterval, $maxInterval));

    // Sleep a determined amount of time before retrieving the operation
    // again.
    printf(
        'Operation %s is still running, sleeping for %d seconds<br>',
        $operationName,
        $sleep
    );
    sleep($sleep);
} while (true);