Datadog exporter resource behavior and mapping

[bnjjj]

Datadog exporter resource behavior and mapping (Issue #5282)

Users of the Datadog trace exporter may have noticed that span and resource naming is not as expected.
Unlike other APMs, Datadog expects static span names, and then uses resource mapping to provide additional context.

The default behavior of the Datadog exporter has now been changed to support this and give a better user experience.

telemetry:
  exporters:
    tracing:
      datadog:
        enabled: true
        # Enables resource mapping, previously disabled by default, but now enabled.
        enable_span_mapping: true
        # Enables fixed span names, defaults to true.
        fixed_span_names: true

  instrumentation:
    spans:
      mode: spec_compliant

The following default resource mappings are applied:

OpenTelemetry Span Name	Datadog Span Operation Name
request	http.route
router	http.route
supergraph	graphql.operation.name
query_planning	graphql.operation.name
subgraph	subgraph.name
subgraph_request	graphql.operation.name
http_request	http.route

You can override the default resource mappings by specifying the resource_mapping configuration:

  exporters:
    tracing:
      datadog:
        enabled: true
        resource_mapping:
          # Use `my.span.attribute` as the resource name for the `router` span
          router: "my.span.attribute"

Fixes #5282

---

#ROUTER-359
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. ↩

[router-perf]

CI performance tests

• step - Basic stress test that steps up the number of users over time
• reload - Reload test over a long period of time at a constant rate of users
• step-with-prometheus - A copy of the step test with the Prometheus metrics exporter enabled
• events_without_dedup_callback - Stress test for events with a lot of users and deduplication DISABLED using callback mode
• events - Stress test for events with a lot of users and deduplication ENABLED
• events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• 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
• xlarge-request - Stress test with 10 MB request payload
• const - Basic stress test that runs with a constant number of users
• 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
• step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• xxlarge-request - Stress test with 100 MB request payload
• demand-control-uninstrumented - A copy of the step test, but with demand control monitoring enabled
• no-graphos - Basic stress test, no GraphOS.
• events_callback - Stress test for events with a lot of users and deduplication ENABLED in callback mode
• large-request - Stress test with a 1 MB request payload
• demand-control-instrumented - A copy of the step test, but with demand control monitoring and metrics enabled

[Samjin]

I think based on this latest comment, we have to use router as the HTTP and Service entry span for now until if Datadog could auto instrument http span someday. I think this change could go in.

[bnjjj]

@BrynCooke Could you see any issues by doing this ? Like breaking existing tracing for our customers on DD ?

[BrynCooke]

I pushed some WIP code to add configuration and integration tests to show that span mapping is working.

[bnjjj]

I can't approve it because I opened that PR but LGTM. Thanks for the refactor around consts it's really nice ! We should do this more often!