[Bug]: Make absl::InitializeLog safe to be called multiple times

[janpfeifer]

Describe the issue

I don't really use absl::log, but a library I depend on uses it. It logs a bunch of "garbage" (unrelated to my project) that appears on the stderr. It includes the message:

WARNING: All log messages before absl::InitializeLog() is called are written to STDERR

Now I'm adding an earlier call in my program to absl::InitializeLog() in an attempt to eliminate the noise. But I noticed the library I use also eventually calls absl::InitializeLog().

Checking the documentation of absl::InitializeLog it's an error to call it more than once.

More generically, a project and one or more of its dependencies may need to call absl::InitializeLog, and there is no way to coordinate this across completely independent libraries -- ideally, libraries should never call it but ... it happens -- see Google's XLA as an example.

Hence my bug/feature request to make InitializeLog safe to be called multiple times -- a no-op if it has already been called.

ps.: I'm no expert on absl library, it's very likely there is nuance I'm missing.

Steps to reproduce the problem

Use two libraries where both call absl::InitializeLog()

What version of Abseil are you using?

Head.

What operating system and version are you using?

Ubuntu, various versions.

What compiler and version are you using?

clang

What build system are you using?

bazel

Additional context

No response

[janpfeifer]

Any considerations on this one ? I bumped into the exact same issue again.

Apparently this is also a dependency, for similar reasons for GRPC Proposal to use Absl Logging.

[AustinSchuh]

Definitely not a great long term strategy since it is an internal API, but the following works in a single threaded environment:

if (!absl::log_internal::IsInitialized()) {
  absl::InitializeLog();
}

Maybe that suggests that should become a public API instead of internal? This bug got mentioned in the glog -> absl conversion for ceres-solver.

[janpfeifer]

Well, if only I had access to all the code (of all dependencies) ... One could also create a wrapper to absl::InitiailzedLog that includes a std::call_once() to the original.

Alas, the issue is that the other libraries that I link call absl::InitailizeLog and I cannot change their code with any of the suggestions. Case in point, I'm not able to change the Abseil library to include such a test inside abls::InitializedLog directly 😄

[h-vetinari]

One could also create a wrapper to absl::InitiailzeLog that includes a std::call_once() to the original.

@derekmauro, would that be an acceptable solution that could be considered for inclusion?

[janpfeifer]

One could also create a wrapper to absl::InitiailzeLog that includes a std::call_once() to the original.

@derekmauro, would that be an acceptable solution that could be considered for inclusion?

Not sure this relative to this bug, but generically this would be a solution if this was done in absl itself. Doing yourself the wrapper, per previous post, doesn't solve the issue because other libraries would call absl::InitializeLog directly.

[h-vetinari]

That's why I'm asking a maintainer on the abseil repo if he would accept that wrapper-approach in abseil. ;-)