A significant amount of errors are coming from worker-abusefilter.js, for example https://logstash.wikimedia.org/app/dashboards#/doc/logstash-*/logstash-2021.02.10?id=YKJ7i3cBjr5R1RLC-QVJ usually a large amount from a single client.
No stack trace provided.
| Subject | Repo | Branch | Lines +/- | |
|---|---|---|---|---|
| Check response code and prevent exception in worker-abusefilter | mediawiki/extensions/AbuseFilter | master | +8 -1 |
The lack of a stacktrace or something is quite problematic, but this is probably the faulty line. Somehow, the API call is not returning valid JSON. It's hard to provide an explanation without knowing what the response was, but personally, 99% of the times I've seen a similar error is because something fails on the PHP side, causing a fatal error. The problem is, I cannot find any error on logstash.
It could possibly be sending the HTML associated with a server error. I've seen those quite frequently. Best to be defensive here and wrap in a try / catch block when using XMLHttpRequest
Yeah, that was my theory, but I couldn't find any AbuseFilter-related error on logstash for that time. Anyway yes, catching any exception seems a good idea. In case of failure, how can I log the response body so it's visible on logstash?
The client should check the status code (and perhaps the content-type) before attempting to parse the response body.
Heh, unfortunately no, otherwise we'd be using mw.Api which would do all these checks for us.
I'm going to implement this, but also adding a try/catch in case of something else that's also unexpected.
Change 663655 had a related patch set uploaded (by Daimona Eaytoy; owner: Daimona Eaytoy):
[mediawiki/extensions/AbuseFilter@master] Check response code and prevent exception in worker-abusefilter
Change 663655 merged by jenkins-bot:
[mediawiki/extensions/AbuseFilter@master] Check response code and prevent exception in worker-abusefilter