feat(integrations): Add tracing to DramatiqIntegration

[Igreh]

Adds tracing support to DramatiqIntegration #3454

[szokeasaurusrex]

Hi @Igreh, I took a quick glance at your PR – at a high level this seems reasonable; however, before I do a full review, I would appreciate if you could please add some tests for these changes, since we need tests before we can consider merging this.

[szokeasaurusrex]

Why are we using a ContextVar here, instead of just a simple instance variable on the SentryMiddleware?

[Igreh]

To isolate variable between threads:

1. Dramatiq can be started in multithreading mode:
   dramatiq --processes 1 --threads 5 ...
2. And I was inspired by official middleware:
   CurrentMessageMiddleware

I will try recheck if it's actually needed

[codecov]

Codecov Report

Attention: Patch coverage is 93.75000% with 1 line in your changes missing coverage. Please review.

Project coverage is 80.72%. Comparing base (6f71a1b) to head (edee89d).
Report is 4 commits behind head on master.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/integrations/dramatiq.py	93.75%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4571      +/-   ##
==========================================
- Coverage   80.74%   80.72%   -0.03%     
==========================================
  Files         156      156              
  Lines       16483    16491       +8     
  Branches     2801     2801              
==========================================
+ Hits        13309    13312       +3     
- Misses       2296     2297       +1     
- Partials      878      882       +4     

Files with missing lines	Coverage Δ
sentry_sdk/integrations/dramatiq.py	81.31% <93.75%> (+0.59%)	⬆️

... and 4 files with indirect coverage changes

[Igreh]

Hi @Igreh, I took a quick glance at your PR – at a high level this seems reasonable; however, before I do a full review, I would appreciate if you could please add some tests for these changes, since we need tests before we can consider merging this.

Hi!
Thanks for reply. I'm not very familiar about what should be tested exactly for now (transaction was successfully started? or what objects/props must be created? and etc ) but I will take a look and try to do my best =)
If you have any advice - would be very helpful

Edit:
Or I just need to cover one missed line?

[sentrivana]

Hey @Igreh, it'd be good to have "end-to-end" (i.e., not unit tests) for the different tracing code paths. Stuff like:

• the happy path (if everything works fine, you get the transaction and it has the data you expect it to have)
• how it behaves if there's an error (a transaction still gets sent, and it has the correct status, etc.; maybe also check if the user's program still behaves as expected -- the exception bubbles up if it should bubble up, etc.)
• trace propagation (i.e., the transaction picks up propagation headers/vars if present) -- I think this might still be missing in your PR

...and/or whatever you consider important so that when the test suite is run and ends up green, you'd have a reasonable amount of confidence that tracing in the Dramatiq integration is working.

You can have a look at some of these similar integrations and their test suites (e.g. arq, huey) for inspiration.

Thanks for working on this! Let us know if you need any help.

[Igreh]

Hi @sentrivana !
Thanks for your reply. It was very helpful.
I believe I was able to solve propagation issue (see last commit)
Also, I've changed the way dramatiq_task_id is stored - now as tag (like in celery). It's actually very convenient to find transaction by ID.
New tests were added (huey integration I used for inspiration).
One thing I can't understand for now: mechanism.type of error event is "logging" instead of "dramatiq". https://github.com/getsentry/sentry-python/pull/4571/files#diff-ed170393871d90a02937ffecacd1b736805e6ea3c43e5549fd0df9bab883709eR82
Disabling LoggingIntegration fixes it (and actually it's the way we use sentry) but I suppose the general solution must work on defaults)
Probably, I have to dig deeper to dramatiq source code to understand what's happening... Not sure but I will keep investigating