Record origin of client requests in metrics

[jpraynaud]

Why

We need to record the origin of the requests which are done on the aggregator REST API in order to have a fine grain monitoring of its usage. This will help separate benchmark traffic, traffic from selected partners,...

How

Implement a feature to optionally record an origin tag requests made to the aggregator and compute the metrics in Grafana and/or protocol dashboard.

What

• Create a list of authorized origin tag:
  • One part is hard-coded: EXPLORER, BENCHMARK, CI, NA
  • The other is done with configuration
• In the client library/WASM, use an optional origin tag set with a specific option (this options adds an HTTP header mithril-origin-tag)
• In the client cli, add an optional command parameter for the origin tag
• In the aggregator benchmarks, use the origin tag BENCHMARK
• In the explorer, use the origin tag EXPLORER
• In the CI, use the origin tag CI for the manual/nightly workflows calling external aggregators
• In the aggregator, add a middleware to the HTTP routes for computing the origin tag:
  • If it is not in the white list: fallback to NA
  • Otherwise use the white listed value
  • Use the computed origin tag in the metrics recording inside the handlers of the routes
  • Update EventMessage with the origin tag when needed
• In the aggregator, extend the metrics:
  • Support recording of a metric with an optional origin tag (and keep supporting metrics without origin tag)
  • Update all the calls to the metrics to support an optional origin tag
  • In the state machine, the calls to the metrics should not be modified (as there is no origin tag in that case)
• Migrations to use the origin tag:
  • ~~event table ( ~800K rows today, is it needed?)~~
  • metrics_per_day view
  • check that there is no degradation in the performances of the metrics_per_day view
• Documentation:
  • How to specify an origin tag in the clients (examples, website)
  • How to setup an aggregator with custom white list of origin tags (website)