While testing T301878, it took a while to end up with the following fix: https://gerrit.wikimedia.org/r/c/machinelearning/liftwing/inference-services/+/814098
Tornado (part of KServe/LiftWing) uses application/x-www-form-urlencoded as Content-Type for its HTTP client (for POSTs), unless explicitly told otherwise (like using Content-type: application/json). In EventGate's logs we found only these traces:
event e1809d3f-db47-493d-bd36-9c0575e63649 of schema at /mediawiki/revision/score/2.0.0 destined to stream unknown encountered an error: Field(s) meta.stream were missing from event and could not be extracted.","time":"2022-07-14T07:25:39.758Z","v":0}
The above error message led us to think that the stream field was not populated for some reason, and the strange thing was that the schema was picked up correctly. After some tests we figure out it was the wrong Content-type, so we thought to open a task to see if the error message could be improved or not :)