Dash webapps: logging errors within callback code?

MarkPundurs

In a dash webapp, I was trying to filter a table by the value selected in a dropdown. It was silently failing to alter the table contents because in the callback function I was calling df.drop('colname') instead of df.drop(columns='colname'). The backend ran without reported error or log file entry.

How can I log such errors? It seems dash's app.run[_server] function has debugging options (https://dash.plotly.com/reference), but that function appears to be called behind the curtains in DSS.

VitaliyD

Hi,

Technically using df.drop('colname') in the callback function should of throw the exception that should be printed in the logs unless you are using try/except or df.drop('colname', errors='ignore') which suppresses the error. However, it is impossible to say more without seeing your code.

Below are the screenshots of my test to confirm the above:

Best,

Vitaliy

MarkPundurs

Was your testing on DSS v11?

VitaliyD

Yes, 11.4.0.