Error with SendSmtpEmail: 'NoneType' object has no attribute 'bio_read' about spidermon HOT 5 OPEN

Spidermon uses scrapy.mail.EmailSender to send emails using SMTP protocol. Such class returns a Deferred object that is never awaited and caused the error logs that you are raising. To fix this we either need to:

• Block until the deferred object has been processed
• Implement the SMTP mailing using an alternative library
• Allow to execute async code on actions and/or return deferreds

cc. @Gallaecio @wRAR @rennerocha

from spidermon.

Rebuild spidermon to support async code would be a Spidermon 2.0 change. I don't think we are considering this in short term 😄

Using blocking Python stlib smtplib for that looks fine to me, and not complicated to do.

from spidermon.

Seems related to scrapy/scrapy#3478

from spidermon.

The analysis makes sense. Blocking until the deferred finishes should be fine if the code allows doing it easily.

from spidermon.

It doesn't look trivial to block on a deferred or rebuild spidermon to support async code, so we should change the current action to use some other smtp library like https://docs.python.org/3/library/smtplib.html instead.

from spidermon.