Skip to content

Fix #2723: Retry on HTTP 400 failedPrecondition#2731

Open
codeXsidd wants to merge 1 commit intogoogleapis:mainfrom
codeXsidd:main
Open

Fix #2723: Retry on HTTP 400 failedPrecondition#2731
codeXsidd wants to merge 1 commit intogoogleapis:mainfrom
codeXsidd:main

Conversation

@codeXsidd
Copy link

Screenshot 2026-03-21 100631 Resolves #2723

Thank you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly:

  • Make sure to open an issue as a bug/issue before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
  • Ensure the tests and linter pass
  • Code coverage does not decrease (if any source code was changed)
  • Appropriate docs were updated (if necessary)

Fixes #<issue_number_goes_here> 🦕

@codeXsidd codeXsidd requested a review from a team as a code owner March 21, 2026 04:44
@product-auto-label product-auto-label bot added the size: m Pull request size is medium. label Mar 21, 2026
@gemini-code-assist
Copy link

Summary of Changes

Hello, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the robustness of the HTTP client by implementing a retry mechanism for specific HTTP 400 Bad Request errors. Previously, only certain 403 Forbidden errors triggered retries; now, the system will also retry requests that fail with a 400 status code if the underlying reason is identified as a failedPrecondition. This change aims to improve the resilience of API calls against transient precondition failures.

Highlights

  • Enhanced Retry Mechanism: The _should_retry_response function was updated to include HTTP 400 (Bad Request) status codes in its retry considerations, specifically for failedPrecondition and preconditionFailed reasons.
  • Expanded Error Handling: The retry logic now explicitly checks for failedPrecondition and preconditionFailed reasons within 400 Bad Request responses, allowing for retries on these specific conditions.
  • New Test Coverage: A new test case, test_retry_400_failed_precondition, was added to verify the correct retry behavior when an HTTP 400 response with a failedPrecondition reason is encountered.
Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature Command Description
Code Review /gemini review Performs a code review for the current pull request in its current state.
Pull Request Summary /gemini summary Provides a summary of the current pull request in its current state.
Comment @gemini-code-assist Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help /gemini help Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for GitHub and other Google products, sign up here.

Footnotes

  1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution.

@google-cla
Copy link

google-cla bot commented Mar 21, 2026

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

Copy link

@gemini-code-assist gemini-code-assist bot left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Code Review

This pull request adds retry logic for HTTP 400 errors with a failedPrecondition reason, which resolves issue #2723. The changes in googleapiclient/http.py correctly implement this by extending the _should_retry_response function. The accompanying tests in tests/test_http.py validate the new behavior. My review includes a suggestion to refactor the retry logic for better maintainability and a recommendation to enhance test coverage for all supported retry reasons. Overall, this is a good improvement.

Comment on lines +140 to +149
if resp_status == http_client.FORBIDDEN:
LOGGER.warning('Encountered 403 Forbidden with reason "%s"', reason)
# Only retry on rate limit related failures.
if reason in ("userRateLimitExceeded", "rateLimitExceeded"):
return True
elif resp_status == http_client.BAD_REQUEST:
LOGGER.warning('Encountered 400 Bad Request with reason "%s"', reason)
# Only retry on precondition failures.
if reason in ("failedPrecondition", "preconditionFailed"):
return True

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

medium

For better maintainability and to make it easier to add more retryable status codes in the future, consider refactoring this if/elif block to be more data-driven. You can use a dictionary to map status codes to their retryable reasons and log messages.

Suggested change
if resp_status == http_client.FORBIDDEN:
LOGGER.warning('Encountered 403 Forbidden with reason "%s"', reason)
# Only retry on rate limit related failures.
if reason in ("userRateLimitExceeded", "rateLimitExceeded"):
return True
elif resp_status == http_client.BAD_REQUEST:
LOGGER.warning('Encountered 400 Bad Request with reason "%s"', reason)
# Only retry on precondition failures.
if reason in ("failedPrecondition", "preconditionFailed"):
return True
RETRYABLE_INFO = {
http_client.FORBIDDEN: {
"reasons": ("userRateLimitExceeded", "rateLimitExceeded"),
"message": 'Encountered 403 Forbidden with reason "%s"',
},
http_client.BAD_REQUEST: {
"reasons": ("failedPrecondition", "preconditionFailed"),
"message": 'Encountered 400 Bad Request with reason "%s"',
},
}
if resp_status in RETRYABLE_INFO:
info = RETRYABLE_INFO[resp_status]
LOGGER.warning(info["message"], reason)
if reason in info["reasons"]:
return True

Comment on lines +1073 to +1099
def test_retry_400_failed_precondition(self):
num_retries = 2
resp_seq = [
({"status": "400"}, FAILED_PRECONDITION_RESPONSE),
({"status": "200"}, "{}")
]
http = HttpMockSequence(resp_seq)
model = JsonModel()
uri = "https://www.googleapis.com/someapi/v1/collection/?foo=bar"
method = "POST"
request = HttpRequest(
http,
model.response,
uri,
method=method,
body="{}",
headers={"content-type": "application/json"},
)

sleeptimes = []
request._sleep = lambda x: sleeptimes.append(x)
request._rand = lambda: 10

request.execute(num_retries=num_retries)

self.assertEqual(1, len(sleeptimes))
self.assertEqual(10 * 2 ** 1, sleeptimes[0])

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

medium

The new test test_retry_400_failed_precondition is great for covering the failedPrecondition reason. However, the implementation in http.py also handles the preconditionFailed reason. It would be beneficial to add a test case for preconditionFailed as well to ensure full coverage of the new logic.

You could achieve this by parameterizing the test or by adding a separate test method for the preconditionFailed case.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

size: m Pull request size is medium.

Projects

None yet

Development

Successfully merging this pull request may close these issues.

HTTP 400 / preconditionFailed should be retried

2 participants