Request timeout and rate limited error responses are structured errors

[IvanGoncharov]

Request timeout (408 Request Timeout) and request rate limited (429 Too Many Requests)errors will now result in a structured GraphQL error (i.e., {"errors": [...]}) being returned to the client rather than a plain-text error as was the case previously.

Also both errors are now properly tracked in telemetry, including apollo_router_graphql_error_total metric.

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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

Fixes: #4891

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. ↩

[router-perf]

CI performance tests

• 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

[bnjjj]

I think it might also be interesting to add more tests for metrics, like is it properly accounted with the right status code and so one

[IvanGoncharov]

I think it might also be interesting to add more tests for metrics, like is it properly accounted with the right status code and so one

@bnjjj I added metrics into integration tests, please take a look

[bnjjj]

Not a blocker, but if you have time could you add a test including configuration with custom telemetry and adding the status_code attributes on http.server.request.duration ?

Something like:

telemetry:
  instrumentation:
    instruments:
      router:
        http.server.request.duration:
          attributes:
            # Standard attributes
            http.response.status_code: true
            graphql.error:
              on_graphql_error: true

Make sure to guard it like here and test it with the right env variables set to enable graphos in tests (TEST_APOLLO_KEY, TEST_APOLLO_GRAPH_REF).