gRPC

Using metadata

https://github.com/grpc/grpc-go/blob/master/Documentation/grpc-metadata.md

Monitoring

• @peterbourgon

one Histogram per service for request duration, label for method (gRPC method, HTTP route, etc.), label for result (gRPC or HTTP status code), 10–20 buckets — should be no problem

• https://alex.dzyoba.com/blog/go-prometheus-service

• Request rate
• Errors
• Duration (latency) distribution

• https://www.weave.works/blog/of-metrics-and-middleware/