Maybe a bug of reopen_files when handle signal USR1 ？

[ysymi]

I am sorry I don't know how to discuss on mailing list.

phenomenon:

when gunicorn received signal USR1, my flask app's logger will write log to another file, which is unexpected.

reason:

my logger in flask app use handler implemented by myself, and my handler does not open file of handler.baseFilename. when gunicorn worker handle USR1, it will search all logger in that gunicorn worker process and reopen the handler's stream by open(handler.baseFilename).

related code:

# loggers method core logic
root = logging.root
existing = root.manager.loggerDict.keys()
return [logging.getLogger(name) for name in existing]

# reopen_files method core logic
for log in loggers():
    for handler in log.handlers:
        if isinstance(handler, logging.FileHandler):
            if handler.stream:
                handler.stream.close()
                handler.stream = open(handler.baseFilename,  handler.mode)

my idea:

To be honest, I do not understand why gunicorn need reopen all logger in a python process , shouldn’t it pick out only gunicorn's logger ？however, if it's really required, the reopen_files logic must be safe or do not have effect to other logger at least.
Many people use their own logger class or handler, they may have different implementation, but, they must overwrite same name method in python logging module. If gunicorn want to reopen all logger, it can use FileHandler's method close and _open(see here, line 898 )to support different custom logger or handler.

I am happy to submit a pr to optimize here :)

[tilgovi]

To be honest, I do not understand why gunicorn need reopen all logger in a python process , shouldn’t it pick out only gunicorn's logger?

I think I agree with that. That would be a small breaking change, so I think I like your other idea. Let's use close and _open. Using a _ method doesn't feel any worse than using two undocumented properties, and at least it can be overridden.

[tilgovi]

I'd review a PR for this.

[ysymi]

@tilgovi thanks for your comment. I will prepare a pr as quickly.
and I want to know, in your opinion, what is purpose of gunicorn need to process all logger (except root logger, of course) ?

[tilgovi]

what is purpose of gunicorn need to process all logger

I cannot remember any discussion of this. It probably just seemed sensible at the time.