Hi everyone i m currently transforming some previous Prefect

Question

Hi everyone i m currently transforming some previous Prefect flow to the Prefect 2 0 i encountered some issues during migration How can I write log into the local file In 1 0 i use python s file handler and add that handler to the Prefect logger However in 2 0 it seems there s no addHandler method in Prefect logger

Zanie · Answer

See <https docs prefect io concepts logs h=logging logging configuration>

Zanie · Answer

Basically we expose all of Python s logging settings to you <https github com PrefectHQ prefect blob orion src prefect logging logging yml>

Tuoyi Zhao · Answer

HI Michael I still not fully understand so you mean I can just add a file handler into the logging yml in handlers section

Andrew Huang · Answer

Maybe this can help too <https discourse prefect io t prefect logging faq 1476>

Tuoyi Zhao · Answer

Thanks < Andrew Huang> but i still have no idea how to add a local file handler directly in the python code is there a handy way to add the File Handler to the Prefect 2 0 logger so the log can be written during flow run

Tuoyi Zhao · Answer

I saw there s way to add extra logger from yaml but is that going to be global instead of flow specific as i only want to log one specific flow

Andrew Huang · Answer

my guess is using logging yml and then <https discourse prefect io t how to add extra loggers to prefect 2 0 1040>

Tuoyi Zhao · Answer

but no way to attach handler directly to Prefect logger

Andrew Huang · Answer

Tuoyi Zhao · Answer

thanks i will do some investigations

Andrew Huang · Answer

great if you figure it out feel free to post on the discourse so it can be shared with others too or reply back here and I can post it for you

Tuoyi Zhao · Answer

< Andrew Huang> I actually figured out a way to add FileHandler to specific flow The part in Italic is the key This solution is similar to the one I used in Prefect 1 0 but I have to add separately to both Flow and Task logger in Prefect 2 0 import prefect from prefect import flow task import logging from datetime import datetime task def string prep ct return ct strftime H M S flow def dynamic parameter ct=datetime now Add File Handler to both flow and task logger flow logger = logging getLogger prefect flow runs task logger = logging getLogger prefect task runs handler = logging FileHandler filename= lt replace with your own log file path gt handler setFormatter logging Formatter asctime s msecs 03d | levelname 7s | name s message s flow logger addHandler handler task logger addHandler handler Actual Flow Part general logger = prefect logging get run logger strings = string prep ct see see + strings

Andrew Huang · Answer

awesome job I ll add to Discourse if you dont mind

Tuoyi Zhao · Answer

Of course wink Hope this will help

Andrew Huang · Answer

<https discourse prefect io t add separate logging filehandlers within python code specific to a flow 1498 > much appreciated

Andrew Huang · Answer

and also linked here for visibility <https discourse prefect io t prefect logging faq 1476>