Capturing and replaying logs from nested functions

Hi! I just started using loguru this week and there is a specific behaviour I want to achieve but I’m not sure how to search for it. Let me provide a very simple example of what I’m talking about:

I have a function that may output logs

def bark():
    logger.info('whoof')

In another part of the code, I want to capture the log and add something before it:

# intercept message coming from bark
bark()
# add something or log something before it
logger.info('A dog will bark')
# replay message from bark

The final output I’m looking for is:

A dog will bark
whoof

The example heavily simplifies my use case, here calling logger.info('A dog will bark') before bark() would solve the issue, but for my use case that is not possible

---

I took a look at InterceptHandler but I don’t think that is related. I’m guessing there is a way to use sinks to achieve this, but I’m not sure how.

[Delgan]

Yeah, that’s because we are calling logger.log() using an “anonymous” level: record["level"].no. We are just passing a level no which is not associated to any color.

We need to pass the record["level"].name instead, but we need first to make sure that such level exist. For example, if you use logger.log(42, "Foobar") somewhere in your code then record["level"].name is equals to "Level 42" but such level is not registered. This becomes a little bit more verbose unfortunately.

for msg in self.deferred:
    record = msg.record
    patched = logger.patch(lambda r: r.update(record))
    level = record["level"].name

    try:
        logger.level(level)
    except ValueError:
        # If the level 'name' is not registered, use its 'no' instead
        level = record["level"].no
        
    patched.log(level, record["message"])

[Delgan]

You can patch() the logger before re-sending the log message in order to update the record dict:

for msg in self.deferred:
    record = msg.record
    patched = logger.patch(lambda r: r.update(record))
    patched.log(record["level"].no, record["message"])