Examples of com.google.api.client.http.ExponentialBackOffPolicy

com.google.api.client.http.ExponentialBackOffPolicy

Implementation of {@link BackOffPolicy} that increases the back off period for each retry attemptusing a randomization function that grows exponentially.

{@link #getNextBackOffMillis()} is calculated using the following formula:

 randomized_interval = retry_interval * (random value in range [1 - randomization_factor, 1 + randomization_factor])

In other words {@link #getNextBackOffMillis()} will range between the randomization factorpercentage below and above the retry interval. For example, using 2 seconds as the base retry interval and 0.5 as the randomization factor, the actual back off period used in the next retry attempt will be between 1 and 3 seconds.

Note: max_interval caps the retry_interval and not the randomized_interval.

If the time elapsed since an {@link ExponentialBackOffPolicy} instance is created goes past themax_elapsed_time then the method {@link #getNextBackOffMillis()} starts returning{@link BackOffPolicy#STOP}. The elapsed time can be reset by calling {@link #reset()}.

Example: The default retry_interval is .5 seconds, default randomization_factor is 0.5, default multiplier is 1.5 and the default max_interval is 1 minute. For 10 requests the sequence will be (values in seconds) and assuming we go over the max_elapsed_time on the 10th request:

 request#     retry_interval     randomized_interval 1             0.5                [0.25,   0.75] 2             0.75               [0.375,  1.125] 3             1.125              [0.562,  1.687] 4             1.687              [0.8435, 2.53] 5             2.53               [1.265,  3.795] 6             3.795              [1.897,  5.692] 7             5.692              [2.846,  8.538] 8             8.538              [4.269, 12.807] 9            12.807              [6.403, 19.210] 10           19.210               {@link BackOffPolicy#STOP}

Implementation is not thread-safe.

@since 1.7 @author Ravi Mistry

          "bytes=" + bytesDownloaded + "-" + (bytesDownloaded + chunkSize - 1));


      if (backOffPolicyEnabled) {
        // Set ExponentialBackOffPolicy as the BackOffPolicy of the HTTP Request which will
        // retry the same request again if there is a server error.
        request.setBackOffPolicy(new ExponentialBackOffPolicy());
      }


      HttpResponse response = request.execute();
      AbstractInputStreamContent.copy(response.getContent(), outputStream);

      }
      request.getHeaders().setRange(rangeHeader.toString());
    }
    // use exponential backoff on server error
    if (backOffPolicyEnabled) {
      request.setBackOffPolicy(new ExponentialBackOffPolicy());
    }
    // execute the request and copy into the output stream
    HttpResponse response = request.execute();
    try {
      IOUtils.copy(response.getContent(), outputStream);

   */
  private HttpResponse executeCurrentRequestWithBackOffAndGZip(HttpRequest request)
      throws IOException {
    // use exponential backoff on server error
    if (backOffPolicyEnabled) {
      request.setBackOffPolicy(new ExponentialBackOffPolicy());
    }
    // enable GZip encoding if necessary
    if (!disableGZipContent && !(request.getContent() instanceof EmptyContent)) {
      request.setEncoding(new GZipEncoding());
    }

Examples of com.google.api.client.http.ExponentialBackOffPolicy

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