One issue with platforms like Heroku is the opaque routing layer. You get a few general metrics from it, but lack visibility into or control over things like:
- chosen routing algorithm (random afaik)
- websocket connections (only logged when a connection completes)
- headers (not loggable)
- time series metrics (none available generally)
It would be interesting to know if we could get insight into any or all of these in the future. One header that does get passed on a few platforms is
X-Request-Start to help understand if requests are queued at before the VM layer. Anyway, just thought I’d raise this topic and see what your thoughts are on routing and visibility.