Consistent logging method

[mwakaba2]

Problem

This closes #605

Two methods in the class ZMQChannelsHandler were using the logging function directly instead of self.log method to emit logs. We already have a default format set for all Jupyter server logs, so this PR updates the following methods' logging calls to keep the format consistent.

• on_kernel_restarted
• on_restart_failed

Changes made

• Replace all logs emitted with direct use of logging with the instantiated class's own logging method: self.log.
• Add optional log parameter to list_running_servers to add missing warning log for failed server info file deletion.

Tests

While trying to reproduce the logs with logging, I found out that logs emitted with the logging function weren't getting propagated.

To reproduce the issue, I tested logging in the ZMQChannelsHandler.on_iopub method - code. (I didn't know how to reproduce/trigger calls to ZMQChannelsHandler.<on_kernel_restarted, on_restart_failed>). I replaced self.log withlogging.

def on_iopub(msg):
            self.log.debug("!!!!!!!!!!! UPDATED LOGGING METHOD")
            logging.debug("Nudge: IOPub received: %s", self.kernel_id)
            if not iopub_future.done():

To emit the logs, I did the following:

1. Start Jupyter server: jupyter server --ServerApp.log_level=DEBUG --ServerApp.jpserver_extensions='{"jupyterlab": True}'
2. Create a python kernel
3. Restarte the python kernel

The "IoPub received" log wasn't emitted.

[D 2021-11-06 10:15:34.214 ServerApp] !!!!!!!!!!! UPDATED LOGGING METHOD
[D 2021-11-06 10:15:34.214 ServerApp] Nudge: resolving iopub future: e1b8b87c-4d10-4782-bad7-50e7cf1cf732
[D 2021-11-06 10:15:34.214 ServerApp] Nudge: shell info reply received: e1b8b87c-4d10-4782-bad7-50e7cf1cf732

With self.log, the logs are emitted:

[D 2021-11-06 10:15:07.030 ServerApp] !!!!!!!!!!! UPDATED LOGGING METHOD
[D 2021-11-06 10:15:07.030 ServerApp] Nudge: IOPub received: 1e48ec11-17c0-487b-bd53-f24bce96617a
[D 2021-11-06 10:15:07.030 ServerApp] Nudge: resolving iopub future: 1e48ec11-17c0-487b-bd53-f24bce96617a
[D 2021-11-06 10:15:07.031 ServerApp] Nudge: shell info reply received: 1e48ec11-17c0-487b-bd53-f24bce96617a

At some point, we may want to figure out a way to encourage usage of self.log instead of logging.

[codecov-commenter]

Codecov Report

Merging #607 (e4a8cb4) into master (3ecb4e0) will decrease coverage by 0.08%.
The diff coverage is 12.50%.

@@            Coverage Diff             @@
##           master     #607      +/-   ##
==========================================
- Coverage   77.42%   77.34%   -0.09%     
==========================================
  Files         110      110              
  Lines       10252    10252              
  Branches     1258     1259       +1     
==========================================
- Hits         7938     7929       -9     
- Misses       1917     1927      +10     
+ Partials      397      396       -1     

Impacted Files	Coverage Δ
jupyter_server/services/kernels/handlers.py	60.82% <0.00%> (-0.11%)	⬇️
jupyter_server/serverapp.py	65.47% <16.66%> (-0.07%)	⬇️
jupyter_server/services/kernels/kernelmanager.py	79.79% <0.00%> (-2.06%)	⬇️
jupyter_server/tests/services/kernels/test_api.py	97.02% <0.00%> (-1.99%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3ecb4e0...e4a8cb4. Read the comment docs.

[mwakaba2]

I also did a quick check for any log.warn usage in the codebase, but I found none. All the warning log calls are using log.warning.

[kevin-bates]

LGTM @mwakaba2 - thank you.

[mlucool]

Thanks!