Logging from "logging" package

Anvil Q&A
1

Hi there
I am using logging package in my server code and I have statements like:

import logging

logging.basicConfig(format='%(asctime)s - %(message)s', level=logging.INFO)
logging.info('My Info Log')

I see these logs don’t appear in App’s Logs.

Is there a way to have these logs in my App’s Logs? Or I need to revert to the good plain old print()?
Logging package is useful and has most of the things you need already built in.

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2

As a practical question, what would you add that is not already in Anvil’s logs?

3

Hi
well at least

  1. leveraging a built-in package designed to this purpose, with levels management, format management and every facility you could think of
  2. avoid refactoring existing codebases to “downgrade” logging management from using the builtin package to cusotm print() statements
  3. keep a single codebase that can run consistently between Anvil’s server environment and Uplinked servers, where built-in logging package is a best practice

I admit this is not indispensable but would be nice.
So, everyone is logging with print statements here?

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4

I haven’t tried this, but what happens if you define a handler that directs to stdout and add that to your logger? Something like:

handler = logging.StreamHandler(sys.stdout)
logger.addHandler(handler)
5

I put together a quick app that demonstrates this working:

https://anvil.works/build#clone:YAV4OHXDRCZOASWG=4RWKKHWLH6N4ZUNBRJ3PJTBN

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6

All great points. Thanks for making me think! :thinking:

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7

Next up: add a handler that also logs to a data table…

I feel an update to my orm coming shortly.

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8

Ouch that was a big miss!
Thanks Owen!
I didn’t event think of that, you’re absolutely right and now that I read it I wonder how didn’t that come up to my mind myself…
This is why this forum is so helpful, I was missing a point as big as a mountain because I was looking at my feet…

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9

Not sure who Paul might be, but you’re welcome. Glad it helped!

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10

Ahahaha my aplogies :innocent:, my messed mind mixed your content with “p.colbert” !!
Thanks Owen and again sorry for that. I fix the attribution immediately. :sweat_smile:

1 Like
11

Would you mind marking this one as solved?

12

To wrap it up

Here you can find ‘logging’ usable within Anvil.
https://anvil-extras.readthedocs.io/en/latest/guides/modules/logging.html

Once it is added to dependencies, you could do

from anvil_extras.logging import Logger, DEBUG
import sys

log = Logger(
    name="user",
    level=DEBUG,
    stream=sys.stdout,
    format="{datetime:%Y-%m-%d %H:%M:%S} | {name} | {level} | {msg}",
)

log.debug("Debug message")
log.info("Info message")
log.error("Something went wrong")

In name="user", I set the name of the Form/Module

So the output is visible on the Running App Console and looks like

2025-10-09 18:08:34 | EventEditorForm | INFO | Hello from foo
2025-10-09 18:08:34 | DashboardForm | DEBUG | Debug message
2025-10-09 18:08:34 | DashboardForm | INFO | Info message
2025-10-09 18:08:34 | DashboardForm | ERROR | Something went wrong
2025-10-09 18:08:34 | DashboardForm | INFO | Hello from foo
2025-10-09 18:08:34 | DashboardForm | INFO | Hello from a
2025-10-09 18:08:34 | DashboardForm | DEBUG | This goes to stdout

img

Feel free to improve.

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