Question: how to use colors properly with custom levels/tags?

[vonpupp]

Hello,

I am trying to have custom colors for custom message types. For instance:
Tag: event1 -> red
Tag: event2 -> blue
Tag: event3 -> white

I first tried to have a custom ColorizedStderrHandler class as shown in this example. However I later noticed on the core features that: custom log levels are not supported, instead we strongly recommend using logging subclasses or log processors that inject tagged information into the log record for this purpose.

I am not sure how to do that, is there any example on how to get different colors with something that emulates custom levels i.e. tags?

Thank you very much.

[vmalloc]

It sounds like you will need to create a custom handler to do that. Once a custom handler is written, you can easily control its emit method to customize the color based on level, channel (a.k.a. logger name) or other information, such as the extra information passed in the extra argument to the logging functions...

[vonpupp]

Thank you for your time and answer. I still don't fully get how the parts play with each other.

I tried this using a TaggingLogger as the base logger:

    log = TaggingLogger(
        'Test',
        [
            'info',
            'warning',
            'debug',
            'event1',
            'event2'
        ]
    )
    my_handler = MyLogHandler({})
    log.handlers.append(my_handler)
    log.event1('Test event1 tag')
    log.event2('Test event2 tag')

When I try write the handler, I am using the TaggingHandler with the ColorizingStreamHandlerMixin to have both functionalities.

class MyLogHandler(ColorizingStreamHandlerMixin, TaggingHandler):

    def get_color(self, record):
        import ipdb; ipdb.set_trace() # BREAKPOINT

    def emit(self, record):
        import ipdb; ipdb.set_trace() # BREAKPOINT
        if 'event1' in record.extra.get('tags', ()):
            record.extra.update({'color': 'red'})

The emit is indeed being called. My initial thought was to add a color key to the extra dict depending on the current tags, so that the get_color would use that color. However, the get_color never gets called.

Also, I am confused on how to use the log method itself with the TaggingLogger, since tags seem to replace the levels, and I would like to have both, I would like something like this:

log.info(['event1'], 'Event1')                # Color red
log.info(['event2'], 'Event2')                # Color green
log.warning(['event1'], 'Warning event1')     # Color blue (any event)
log.warning(['event2'], 'Warning event2')     # Color blue (any event)
log.debug(['event1'], 'Debug event1')         # Color cyan (only event 1)
log.debug(['event2'], 'Debug event2')         # Color magenta (only event 2)

I am not sure how to achieve this with a TaggingLogger.

Thank you once again.

[vmalloc]

Your code above doesn't seem to be using Logbook loggers... the "handlers.append" approach is the way the native logging library is usually used...