Where is local logs for Python on Azure App Service?

Question

if I run locally, I can see my print() texts. But even after enable File System App Service Logs, I still don't see any logs, both in _docker.log or streaming log. What is the right way to generate local logs for Python on Azure App Service?

Answer 1

To close the loop, I ended up making a simple log method

def writeLog(log: str):
    basepath = path.dirname(__file__)
    today = date.today()
    filepath = path.abspath(path.join(basepath, "..", "..", "LogFiles", "MyBot_" + today.strftime("%Y-%m-%d") + ".log"))
    f = open(filepath, "a+")
    f.write(today.strftime("%Y-%m-%d %H:%M:%S") + " " + log)
    f.write("\n")
    f.close()

If I don't close() , I won't be able to download the file. Putting it in LogFiles together with other log files makes it easier to view from VS Code

Answer 2

I test with a Flask web and set the WSGI_LOG follow this doc: Configure the FastCGI handler , it will create the log however the logs file only have the StdErr log, about StdOut it's always blank.

So I use another solution to redirect the standard output of your scripts to some log file.

import sys
sys.stdout = open('D:\\home\\LogFiles\\app.log', 'w')
print("test")

You can configure the above code, then publish your code and run it.

Answer 3

I was encountering a similar issue. In my case the logging was inconsistent in relation to the other logs in the container. In the end it seemed to be more of a log buffering issue, rather than something specific to Azure App Service. It was solved by setting the following environment variable in Azure App Service: Settings -> Container -> Application Settings

PYTHONUNBUFFERED = 1

In a docker run command you'd set it as:

--env PYTHONUNBUFFERED=1