Turn off color logging prefix

[maxliuofficial]

Why are these changes needed?

This pr adds optionality to turn off color logging from actors. This is useful in the case where the logs are outputted to a location that does not support ansi codes, which leads to messy logs.

Similarly to multi color logging, this option uses the RAY_COLOR_PREFIX env var, this time when set to 0. Slightly differently, setting to 0 disables all color logging, even the special cases of raylet / autoscaler. This seems like the more correct approach given the use case.

I also updated the relevant docs (lmk if there are any other relevant docs to this). Here is a screenshot of the local build.

I didn't see any existing corresponding test file for this file, so I created one, and added some tests for this change. Please advise if there is a better place these tests should go, thanks!

Related issue number

Resolves #6855.

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[aslonnie]

maybe RAY_LOG_COLOR or something? I think it is better to make it clear that this is related to logs.

and if I would want to disable color, I would want to also disable it for the log line, not only the prefix.

[maxliuofficial]

maybe RAY_LOG_COLOR or something? I think it is better to make it clear that this is related to logs.

I was aiming for consistency with the existing usage of RAY_COLOR_PREFIX=1 which turns on multi color. It seemed like reusing the same env var made sense. Unless the suggestion is to change both, in which case it might be necessary to have a deprecation period for users that already are setting the existing env var somewhere? Lmk ur thoughts, I am open to changing this!

[maxliuofficial]

and if I would want to disable color, I would want to also disable it for the log line, not only the prefix.

Looks like the color wrapping only applies for the prefix based on this code. Lmk if I missed something somewhere else.

[maxliuofficial]

Please advise on failing rllib test, appears to be unrelated.

[aslonnie]

@jjyao could you get some one from core team to review?

@maxliuofficial maybe sync your branch with latest master head.

[jjyao]

lg, thanks for the contribution!