GraphQL: Capture user-provided error extension values

[marcotc]

A follow up from #4177, this PR allows users to capture custom error fields (called extensions in GraphQL).

Here's an example of an error with extensions (link):

{
  "errors": [
    {
      "message": "Cannot query field \"__typenam\" on type \"Query\".",
      "locations": [
        {
          "line": 1,
          "column": 2
        }
      ],
      "extensions": {
        "code": "GRAPHQL_VALIDATION_FAILED",
        "stacktrace": [
          "GraphQLError: Cannot query field \"__typenam\" on type \"Query\".",
          "    at Object.Field (/my_project/node_modules/graphql/validation/rules/FieldsOnCorrectTypeRule.js:48:31)",
          "    ...additional lines..."
        ]
      }
    }
  ]
}

extensions can contain any arbitrary data, but are often important for error debugging.
Because extensions can contain PII, or pretty much any arbitrary user-provided information, the extensions that are allowed to be capture by dd-trace-rb have to be added to a list in the DD_TRACE_GRAPHQL_ERROR_EXTENSIONS configuration.

Change log entry
No. This will be covered by #4177.

How to test the change?
All changes have automated tests.

[github-actions]

Thank you for updating Change log entry section 👏

^{Visited at: 2025-01-31 22:26:52 UTC}

[datadog-datadog-prod-us1]

Datadog Report

Branch report: graphql-error-event-ext
Commit report: 1209efb
Test service: dd-trace-rb

✅ 0 Failed, 22132 Passed, 1477 Skipped, 5m 39.79s Total Time
⌛ 1 Performance Regression

⌛ Performance Regressions vs Default Branch (1)

• Rails integration tests for an application with a basic route POST request with an event-triggering request in application/x-www-form-url-encoded body behaves like normal with tracing disable is expected to have 0 items - rspec 3.59s (+3.03s, +542%) - Details

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-01-31 22:30:13

Comparing candidate commit 1209efb in PR branch graphql-error-event-ext with baseline commit cf6efdc in branch graphql-error-event.

Found 2 performance improvements and 0 performance regressions! Performance is the same for 29 metrics, 2 unstable metrics.

scenario:profiler - sample timeline=false

• 🟩 throughput [+0.389op/s; +0.403op/s] or [+6.960%; +7.200%]

scenario:tracing - Propagation - Trace Context

• 🟩 throughput [+3738.461op/s; +3845.088op/s] or [+10.971%; +11.283%]

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.73%. Comparing base (cf6efdc) to head (1209efb).

Additional details and impacted files

@@                   Coverage Diff                   @@
##           graphql-error-event    #4325      +/-   ##
=======================================================
+ Coverage                97.72%   97.73%   +0.01%     
=======================================================
  Files                     1368     1370       +2     
  Lines                    83046    83127      +81     
  Branches                  4222     4228       +6     
=======================================================
+ Hits                     81157    81245      +88     
+ Misses                    1889     1882       -7     

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[buraizu]

Approving with a minor update requested

[buraizu]

Suggested change

	| `error_extensions` | `DD_TRACE_GRAPHQL_ERROR_EXTENSIONS` | `Array` | List of extensions keys to include in the span event reported for GraphQL queries with errors. | `[]` |
	| `error_extensions` | `DD_TRACE_GRAPHQL_ERROR_EXTENSIONS` | `Array` | List of extension keys to include in the span event reported for GraphQL queries with errors. | `[]` |