Investigate missing operation from jaeger-query metrics reader

[albertteoh]

Describe the bug

Context: jaegertracing/jaeger-ui#815 (comment)

To Reproduce
Steps to reproduce the behavior:

1. cd docker-compose/monitor/
2. docker-compose up
3. /api/metrics/latencies?service=driver&endTs=1636969517360&groupByOperation=true&lookback=7200000&quantile=0.95&ratePer=3600000&step=60000
4. (Need to confirm) only receiving metrics for operation /FindNearest.
5. From main Jaeger UI Search tab, select driver service. Both /FindNearest and HTTP GET operations are present.

Expected behavior
Receive latency metrics for two operations:

• HTTP GET
• /FindNearest

Version (please complete the following information):

• OS: MacOS
• Jaeger version: master
• Deployment: dev

[Ashmita152]

The prometheus query executed while hitting /api/metrics/latencies has label filter as span_kind =~ "SPAN_KIND_SERVER" while the operation HTTP GET has label span_kind = "SPAN_KIND_CLIENT". Hence it gets filtered out.

[albertteoh]

Ah, thanks for investigating, @Ashmita152!

Yes, it's all coming back to me now; we filter on SPAN_KIND_SERVER because we want to aggregate on ingress rather than egress requests (the latter wouldn't make sense IMO).

I'll close this ticket since it's expected (although potentially confusing) behaviour. I'll include this note in the documentation task for ATM.