plugins/fleet_detector: add schema and persisted_queries gauges

[loshz]

Adds an additional metric to the fleet_detector plugin in the form of: apollo.router.instance.schema with 2 attributes: schema_hash and launch_id.

In order to pass a launch_id to the plugin builder, changes were made to the UpdateSchema variant of the Event enum in order to pass a new SchemaState struct instead of just an SDL string.

Tested via using OpenTelemetry Collector with the following router config and OTEL config

telemetry:
  apollo:
    experimental_otlp_endpoint: "http://0.0.0.0:4317"
  instrumentation:
    spans:
      mode: "spec_compliant"

receivers:
  otlp:
    protocols:
      grpc:
      http:

exporters:
  debug:
    verbosity: detailed

processors:
  batch:
  filter:
    metrics:
      include:
        match_type: regexp
        metric_names:
          - apollo.router.instance.*

service:
  pipelines:
    metrics:
      receivers: [otlp]
      processors: [filter]
      exporters: [debug]

Metric #4
Descriptor:
     -> Name: apollo.router.instance.schema
     -> Description: Details about the current in-use schema
     -> Unit:
     -> DataType: Gauge
NumberDataPoints #0
Data point attributes:
     -> schema_hash: Str(49d5a7e330fea60ef11b282d29f6441d1723a06d2edf3dc8a7985144e4a43a96)
StartTimestamp: 1970-01-01 00:00:00 +0000 UTC
Timestamp: 2024-12-05 14:26:08.704042 +0000 UTC

---

Checklist

Complete the checklist (and note appropriate exceptions) before the PR is marked ready-for-review.

• Changes are compatible¹
• Documentation² completed
• Performance impact assessed and acceptable
• Tests added and passing³
  • Unit Tests
  • Integration Tests
  • Manual Tests

Exceptions

Note any exceptions here

Notes

Footnotes

1. It may be appropriate to bring upcoming changes to the attention of other (impacted) groups. Please endeavour to do this before seeking PR approval. The mechanism for doing this will vary considerably, so use your judgement as to how and when to do this. ↩

2. Configuration is an important part of many changes. Where applicable please try to document configuration examples. ↩

3. Tick whichever testing boxes are applicable. If you are adding Manual Tests, please document the manual testing (extensively) in the Exceptions. ↩

[svc-apollo-docs]

✅ Docs Preview Ready

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[router-perf]

CI performance tests

• connectors-const - Connectors stress test that runs with a constant number of users
• const - Basic stress test that runs with a constant number of users
• demand-control-instrumented - A copy of the step test, but with demand control monitoring and metrics enabled
• demand-control-uninstrumented - A copy of the step test, but with demand control monitoring enabled
• enhanced-signature - Enhanced signature enabled
• events - Stress test for events with a lot of users and deduplication ENABLED
• events_big_cap_high_rate - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity
• events_big_cap_high_rate_callback - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity using callback mode
• events_callback - Stress test for events with a lot of users and deduplication ENABLED in callback mode
• events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• events_without_dedup_callback - Stress test for events with a lot of users and deduplication DISABLED using callback mode
• extended-reference-mode - Extended reference mode enabled
• large-request - Stress test with a 1 MB request payload
• no-tracing - Basic stress test, no tracing
• reload - Reload test over a long period of time at a constant rate of users
• step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• step-local-metrics - Field stats that are generated from the router rather than FTV1
• step-with-prometheus - A copy of the step test with the Prometheus metrics exporter enabled
• step - Basic stress test that steps up the number of users over time
• xlarge-request - Stress test with 10 MB request payload
• xxlarge-request - Stress test with 100 MB request payload

[loshz]

Marking this ready for initial review so I can get feedback before fixing tests and pulling launch_id from uplink.

[jonathanrainer]

LGTM