ERROR: httplib2 transport does not support per-request timeout. Set the timeout when constructing the httplib2.Http instance.

[byronmccollum]

Environment details

• OS: Linux / Docker / Kubernetes (GKE)
• Python version: 3.13.3
• pip version: 25.0.1
• google-auth version: 2.39.0

After upgrading to 2.39.0, starting getting the following error being logged:

httplib2 transport does not support per-request timeout. Set the timeout when constructing the httplib2.Http instance.

Reverting to 2.38.0 suppresses the above error. I suspect it might be related to #1699.

[byronmccollum]

Here is a reproduction of the issues:

test.py

import logging
from google.auth import compute_engine
from googleapiclient import discovery

logging.basicConfig(
    format="%(asctime)s %(levelname)-8s %(message)s", level="INFO"
)

credentials = compute_engine.Credentials(scopes=[])

cloudasset_service = discovery.build(
    "cloudasset", "v1", credentials=credentials
)

request = cloudasset_service.v1().searchAllIamPolicies(
    scope="projects/my-project",
    pageSize=500,
)

response = request.execute()

logging.info(f"Results: {str(len(response.get('results')))}")

---

google-auth==2.38.0

(.venv) root@instance-20250709-145032:~# pip show google-auth
Name: google-auth
Version: 2.38.0
Summary: Google Authentication Library
Home-page: https://github.com/googleapis/google-auth-library-python
Author: Google Cloud Platform
Author-email: googleapis-packages@google.com
License: Apache 2.0
Location: /root/.venv/lib/python3.13/site-packages
Requires: cachetools, pyasn1-modules, rsa
Required-by: google-api-core, google-api-python-client, google-auth-httplib2, google-auth-oauthlib, google-cloud-appengine-logging, google-cloud-core, google-cloud-logging

(.venv) root@instance-20250709-145032:~# python3 test.py 
2025-07-09 16:11:13,582 INFO     file_cache is only supported with oauth2client<4.0.0
2025-07-09 16:11:13,888 INFO     Results: 6

---

google-auth==2.39.0

(.venv) root@instance-20250709-145032:~# pip show google-auth
Name: google-auth
Version: 2.39.0
Summary: Google Authentication Library
Home-page: https://github.com/googleapis/google-auth-library-python
Author: Google Cloud Platform
Author-email: googleapis-packages@google.com
License: Apache 2.0
Location: /root/.venv/lib/python3.13/site-packages
Requires: cachetools, pyasn1-modules, rsa
Required-by: google-api-core, google-api-python-client, google-auth-httplib2, google-auth-oauthlib, google-cloud-appengine-logging, google-cloud-core, google-cloud-logging

(.venv) root@instance-20250709-145032:~# python3 test.py 
2025-07-09 16:11:36,053 INFO     file_cache is only supported with oauth2client<4.0.0
2025-07-09 16:11:36,151 WARNING  httplib2 transport does not support per-request timeout. Set the timeout when constructing the httplib2.Http instance.
2025-07-09 16:11:36,153 WARNING  httplib2 transport does not support per-request timeout. Set the timeout when constructing the httplib2.Http instance.
2025-07-09 16:11:36,320 INFO     Results: 6

[harkamaljot]

@byronmccollum I am unable to reproduce this warning. A the client is selected by google-api-python-client can you share pip show output there, for reference this my output

Name: google-api-python-client
Version: 2.176.0
Summary: Google API Client Library for Python
Home-page: https://github.com/googleapis/google-api-python-client/
Author: Google LLC
Author-email: googleapis-packages@google.com
License: Apache 2.0
Location: /usr/local/google/home/harkamalj/.pyenv/versions/3.8.1/lib/python3.8/site-packages
Requires: google-api-core, google-auth, google-auth-httplib2, httplib2, uritemplate
Required-by:

and I don't see any warnings.

[np5]

I can see the same warnings:

from googleapiclient import discovery
client = discovery.build('compute', 'v1', cache_discovery=False)
client.zones().list(project="PROJECT_ID").execute()

No warning in that case:

from google.cloud import compute_v1
client = compute_v1.ZonesClient()
client.list(project="PROJECT_ID")

Versions:

google-api-core==2.25.1
google-api-python-client==2.176.0
google-auth==2.40.3
google-auth-httplib2==0.2.0
google-cloud-compute==1.33.0
google-cloud-core==2.4.3
google-crc32c==1.7.1
google-resumable-media==2.7.2
googleapis-common-protos==1.70.0
grpc-google-iam-v1==0.14.2

[adityakaldate21-dev]

import httplib2
from google.auth import compute_engine
from googleapiclient.discovery import build
import logging

logging.basicConfig(format="%(asctime)s %(levelname)-8s %(message)s", level=logging.INFO)

Custom Http instance with timeout

http_with_timeout = httplib2.Http(timeout=60) # set your preferred timeout in seconds

Compute Engine credentials

credentials = compute_engine.Credentials()

Apply authorized credentials to the custom HTTP object

http_with_timeout = credentials.authorize(http_with_timeout)

Build the service using the custom transport

cloudasset_service = build("cloudasset", "v1", credentials=credentials, http=http_with_timeout)

Search all IAM policies

request = cloudasset_service.v1().searchAllIamPolicies(scope="projects/my-project", pageSize=500)
response = request.execute()

logging.info(f"Results: {len(response.get('results', []))}")

why does this works?
In simpler terms, you're running into that timeout error because the googleapiclient.discovery library depends on an older HTTP system (httplib2) that doesn’t let you set a timeout for each API call unless you manually provide a custom setup. So, to fix it, you pass in a custom Http() object with a defined timeout when building the service client—this ensures your requests don’t hang indefinitely. Newer Google Cloud libraries (like google-cloud-compute) don’t have this issue because they’re built on modern transport systems like gRPC or requests, which already handle timeouts smartly, meaning fewer headaches and cleaner code.