[Python] Resolve absl::InitializeLog warning by sreenithi · Pull Request #39779 · grpc/grpc

sreenithi · 2025-06-06T15:05:04Z

After Core recently changed its logging system to use absl logging, gRPC python users started seeing the warning log
WARNING: All log messages before absl::InitializeLog() is called are written to STDERR.

This issue especially affects users who are indirect users of the gRPC Python library too, such as Gemini API users.

absl::InitializeLog() is a C++ library that cannot directly be called in the Python layer. It is hence added in the Cython layer at the time of initializing.
The Python layer so far did not have a dependency on the absl library, hence this PR also adds an external dependency on absl/log:initialize

Design gRFC for this: grpc/proposal#505

However, abseil-cpp currently doesn't allow absl::InitializeLog() to be called more than once, and will result in an error like:

[globals.cc : 104] RAW: absl::log_internal::SetTimeZone() has already been called

The changes in this PR may hence cause problems to a small percentage of users with a custom build that's linking directly against gRPC Cython code, and then call absl::InitializeLog() (directly or transitively).

To solve this problem, this PR also introduces a new environment variable GRPC_PYTHON_DISABLE_ABSL_INIT_LOG that will allow users to opt-out of this automatic abseil log initialization when set.

This reverts commit f911f93.

This reverts commit 081df03.

This reverts commit 0931bef.

sergiitk · 2025-07-02T03:53:52Z

src/python/grpcio/grpc/_cython/cygrpc.pyx

 # initialize gRPC
 #
 cdef _initialize():
+  InitializeLog()


Do we know that _initialize is called exactly once even if client code imports grpc multiple times? If not, we should have an internal state to check if we have already initialized it.

asheshvidyut · 2026-01-09T11:58:30Z

src/python/grpcio/grpc/_cython/cygrpc.pyx

+  if not _disable_absl_init_log:
+    InitializeLog()
+  # grpc-oss-only-end
+


Suggested change

This was visible in the import cl internally.

sergiitk · 2026-01-13T03:31:05Z

src/python/grpcio/grpc/_cython/cygrpc.pxd


 include "_cygrpc/grpc.pxi"

+# grpc-oss-only-begin


We're already stripping unnecessary code from absl.pxi, no need to exclude it here too

sergiitk · 2026-01-13T03:36:29Z

src/python/grpcio/grpc/_cython/cygrpc.pyx

 include "_cygrpc/aio/server.pyx.pxi"

+# grpc-oss-only-begin
+cdef bint _disable_absl_init_log = os.environ.get("GRPC_PYTHON_DISABLE_ABSL_INIT_LOG", "")


I don't like the implicit cast to a bool. Maybe something like this?

Suggested change

cdef bint _disable_absl_init_log = os.environ.get("GRPC_PYTHON_DISABLE_ABSL_INIT_LOG", "")

cdef bint _disable_absl_init_log = os.environ.get("GRPC_PYTHON_DISABLE_ABSL_INIT_LOG", "") in {"1", "t", "true", "y", "yes"}

I got the set from gpr_parse_bool_value:

grpc/src/core/util/string.cc

Lines 323 to 325 in ae8671e

bool gpr_parse_bool_value(const char* value, bool* dst) {

const char* kTrue[] = {"1", "t", "true", "y", "yes"};

const char* kFalse[] = {"0", "f", "false", "n", "no"};

I'm also ok with using this method directly, but it'll be a bit more complex. Something like

cdef bint _absl_init_log_env_is_set = 0 cdef bint _absl_init_log_env_is_parsed = gpr_parse_bool_value(os.environ.get("GRPC_PYTHON_DISABLE_ABSL_INIT_LOG", "").encode(), &_absl_init_log_env_is_set) cdef bint _disable_absl_init_log = _absl_init_log_env_is_parsed && _absl_init_log_env_is_set

Note: not tested and not sure this'll work as we want

Though eventually it may not be a bad idea to add a wrapper around this, something like _parse_truthy_env(env_var_name: str) -> bool.

Proposes changes to Abseil logging initialization in gRPC Python to resolve the issue the absl warning `All log messages before absl::InitializeLog() is called are written to STDERR`. Related: - Bug report: grpc/grpc#38703 - Implementation PoC: grpc/grpc#39779 - b/423754102

sergiitk · 2026-02-03T04:36:58Z

src/python/grpcio/grpc/_cython/cygrpc.pyx

 include "_cygrpc/aio/channel.pyx.pxi"
 include "_cygrpc/aio/server.pyx.pxi"

+# Include only for OSS


Not sure we need this comment anymore

sergiitk · 2026-02-03T19:45:03Z

Internal changes rolled back (ref cl/864955066), need to re-apply them again.

sergiitk · 2026-02-04T16:22:31Z

New internal change: cl/865415667

sergiitk · 2026-02-12T00:26:27Z

Reopening, as the change was rolled back in 1aefa48 (cl/865459236).

Fixes grpc#38703 After Core recently changed its logging system to use absl logging, gRPC python users started seeing the warning log `WARNING: All log messages before absl::InitializeLog() is called are written to STDERR.` This issue especially affects users who are indirect users of the gRPC Python library too, such as Gemini API users. `absl::InitializeLog()` is a C++ library that cannot directly be called in the Python layer. It is hence added in the Cython layer at the time of initializing. The Python layer so far did not have a dependency on the absl library, hence this PR also adds an external dependency on `absl/log:initialize` Design gRFC for this: grpc/proposal#505 Closes grpc#39779 COPYBARA_INTEGRATE_REVIEW=grpc#39779 from sreenithi:absl_init_log_python 59eb1e5 PiperOrigin-RevId: 869586957

Backport of #39779 to v1.78.x. --- Fixes #38703 After Core recently changed its logging system to use absl logging, gRPC python users started seeing the warning log `WARNING: All log messages before absl::InitializeLog() is called are written to STDERR.` This issue especially affects users who are indirect users of the gRPC Python library too, such as Gemini API users. `absl::InitializeLog()` is a C++ library that cannot directly be called in the Python layer. It is hence added in the Cython layer at the time of initializing. The Python layer so far did not have a dependency on the absl library, hence this PR also adds an external dependency on `absl/log:initialize` Design gRFC for this: grpc/proposal#505 However, abseil-cpp currently [doesn't allow `absl::InitializeLog()` to be called more than once](abseil/abseil-cpp#1656), and will result in an error like: ``` [globals.cc : 104] RAW: absl::log_internal::SetTimeZone() has already been called ``` The changes in this PR may hence cause problems to a small percentage of users with a custom build that's linking directly against gRPC Cython code, and then call absl::InitializeLog() (directly or transitively). To solve this problem, this PR also introduces a new environment variable `GRPC_PYTHON_DISABLE_ABSL_INIT_LOG` that will allow users to opt-out of this automatic abseil log initialization when set.

add absl::InitializeLog with external dependency

d6d95a7

sreenithi requested review from asheshvidyut and sergiitk June 6, 2025 15:05

sreenithi self-assigned this Jun 6, 2025

sreenithi added lang/Python release notes: yes Indicates if PR needs to be in release notes labels Jun 6, 2025

sreenithi marked this pull request as draft June 6, 2025 15:27

sreenithi removed request for asheshvidyut and sergiitk June 6, 2025 15:33

try alternative dependency

e153e5b

grpc-checks bot added per-call-memory/neutral per-channel-memory/neutral bloat/none labels Jun 6, 2025

asheshvidyut force-pushed the absl_init_log_python branch from b9e6de8 to e153e5b Compare June 7, 2025 05:49

add absl/log/initialize as grpc core dependency

f911f93

github-actions bot added the lang/ruby label Jun 10, 2025

sreenithi added 12 commits June 17, 2025 07:17

Revert "add absl/log/initialize as grpc core dependency"

931479a

This reverts commit f911f93.

try direct dependency for python again

b183f79

add missing dep

7ddab89

add abseil-cpp dependency to Cython setup.py extensions

c1fd510

add full path of initialize file instead of directory

8ce8238

temp disable tests for faster CI runtime

081df03

Revert "temp disable tests for faster CI runtime"

ec43637

This reverts commit 081df03.

remove unwanted code

5a6523b

remove newline

2290648

remove commented code

d37f59b

rename functions

0931bef

Revert "rename functions"

ed1c7a7

This reverts commit 0931bef.

sergiitk self-requested a review June 19, 2025 05:53

sergiitk reviewed Jul 2, 2025

View reviewed changes

sergiitk added the disposition/Needs Internal Changes label Jan 6, 2026

asheshvidyut reviewed Jan 9, 2026

View reviewed changes

sergiitk requested changes Jan 13, 2026

View reviewed changes

sreenithi added 3 commits January 27, 2026 14:17

Merge branch 'master' into absl_init_log_python

ca8313e

separate initializeLog call into a separate file

2960839

update env variable cast to bint

80ac638

sergiitk approved these changes Feb 3, 2026

View reviewed changes

sergiitk removed lang/ruby disposition/Needs Internal Changes labels Feb 3, 2026

sreenithi added 2 commits February 3, 2026 17:37

Merge branch 'master' into absl_init_log_python

0d6a4e9

remove comment and rearrange import order

d53d529

sergiitk added the disposition/Needs Internal Changes label Feb 3, 2026

sergiitk removed the disposition/Needs Internal Changes label Feb 4, 2026

ctiller closed this in b2925a0 Feb 4, 2026

sergiitk reopened this Feb 12, 2026

sreenithi added 2 commits February 12, 2026 07:56

update copyright year

69c8c0c

Merge branch 'master' into absl_init_log_python

59eb1e5

copybara-service bot closed this in 7328158 Feb 13, 2026

sreenithi mentioned this pull request Feb 16, 2026

[Backport][v1.78.x][Python] Resolve absl::InitializeLog warning #41639

Merged

sreenithi mentioned this pull request Feb 23, 2026

1.78.1: Error building Python wheel due to hardcoded dependency on vendored abseil #41696

Open

sergiitk mentioned this pull request Feb 24, 2026

[Python] grpcio==1.78.1 in python fails with certain googleapis like secrets manager, pubsub, bigquery, workflows (through its sdk) from Cloud Run Functions #41725

Open

sreenithi mentioned this pull request Mar 6, 2026

[Python] Fix GRPC_TRACE and add test to check the GRPC_TRACE logs print #41814

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[Python] Resolve absl::InitializeLog warning#39779

[Python] Resolve absl::InitializeLog warning#39779
sreenithi wants to merge 34 commits intogrpc:masterfrom
sreenithi:absl_init_log_python

sreenithi commented Jun 6, 2025 •

edited

Loading

Uh oh!

sergiitk Jul 2, 2025

Uh oh!

asheshvidyut Jan 9, 2026

Uh oh!

asheshvidyut Jan 9, 2026

Uh oh!

sergiitk Jan 13, 2026

Uh oh!

sergiitk Jan 13, 2026

Uh oh!

sergiitk Jan 13, 2026 •

edited

Loading

Uh oh!

sergiitk Jan 13, 2026

Uh oh!

sergiitk Feb 3, 2026

Uh oh!

sergiitk commented Feb 3, 2026 •

edited

Loading

Uh oh!

sergiitk commented Feb 4, 2026

Uh oh!

sergiitk commented Feb 12, 2026 •

edited

Loading

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

	cdef bint _disable_absl_init_log = os.environ.get("GRPC_PYTHON_DISABLE_ABSL_INIT_LOG", "")
	cdef bint _disable_absl_init_log = os.environ.get("GRPC_PYTHON_DISABLE_ABSL_INIT_LOG", "") in {"1", "t", "true", "y", "yes"}

	bool gpr_parse_bool_value(const char* value, bool* dst) {
	const char* kTrue[] = {"1", "t", "true", "y", "yes"};
	const char* kFalse[] = {"0", "f", "false", "n", "no"};

Conversation

sreenithi commented Jun 6, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

sergiitk Jul 2, 2025

Choose a reason for hiding this comment

Uh oh!

asheshvidyut Jan 9, 2026

Choose a reason for hiding this comment

Uh oh!

asheshvidyut Jan 9, 2026

Choose a reason for hiding this comment

Uh oh!

sergiitk Jan 13, 2026

Choose a reason for hiding this comment

Uh oh!

sergiitk Jan 13, 2026

Choose a reason for hiding this comment

Uh oh!

sergiitk Jan 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

sergiitk Jan 13, 2026

Choose a reason for hiding this comment

Uh oh!

sergiitk Feb 3, 2026

Choose a reason for hiding this comment

Uh oh!

sergiitk commented Feb 3, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

sergiitk commented Feb 4, 2026

Uh oh!

sergiitk commented Feb 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

sreenithi commented Jun 6, 2025 •

edited

Loading

sergiitk Jan 13, 2026 •

edited

Loading

sergiitk commented Feb 3, 2026 •

edited

Loading

sergiitk commented Feb 12, 2026 •

edited

Loading