[SVLS-7168] Create GCP PubSub Push Subscriptions Plugin

[nina9753]

What does this PR do?

Extends the official PubSub plugin capabilities and optimizes Datadog tracing instrumentation for Google Cloud Pub/Sub push messages and Cloud Events across all Node.js web frameworks.

• Automatic Detection: No configuration needed
• Large Payloads: Supports up to 10MB efficiently
• All Frameworks: Works with Express, Fastify, Hapi, Koa, etc.
• Distributed Tracing: Maintains trace context across services
• Production Ready: Comprehensive error handling

GCP sends push → HTTP server receives POST request
Plugin detects → "This is a Pub/Sub push!" (via User-Agent: APIs-Google)
Plugin creates → HTTP span as child of PubSub span
Express inherits → Express spans inherit via scope activation
Your app processes → Business logic with automatic tracing

This makes the spans have this hierarchy :
http.request (manually created as child)
└── express.request (inherits via scope activation)
└── express.middleware (inherits via scope activation)
└── your-business-logic (main.js)

Follow-up PR will be opened to create the synthetic span in the flame graph

Motivation

An inferred span for the HTTP push post to the Cloud Run service from a pub/sub topic
Example full Push Direct Span of a cloud run service triggering another service using a direct push subscription
Example full Eventarc pubsub trigger span of a cloud run service triggering another service using an Eventarc cloud event trigger

Plugin Checklist

• Unit tests.
• Integration tests.
• Benchmarks.
• TypeScript definitions.
• TypeScript tests.
• API documentation.
• CI jobs/workflows.

Additional Notes

The changes had to be made in server.js because in Push Subscription, the Cloud Run Service receives HTTP Requests.

• Google Cloud Pub/Sub acts as the HTTP client
• The cloud run service acts as the HTTP server
• GCP topic pushes TO the cloud run service via HTTP POST requests
• Then the cloud run service receives the pushed messages

Additional information can be found in this doc

[github-actions]

Overall package size

Self size: 11.92 MB
Deduped: 111.53 MB
No deduping: 111.87 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/libdatadog | 0.7.0 | 35.02 MB | 35.02 MB | | @datadog/native-appsec | 10.1.0 | 20.37 MB | 20.37 MB | | @datadog/native-iast-taint-tracking | 4.0.0 | 11.72 MB | 11.73 MB | | @datadog/pprof | 5.9.0 | 9.77 MB | 10.1 MB | | @opentelemetry/core | 1.30.1 | 908.66 kB | 7.16 MB | | protobufjs | 7.5.4 | 2.95 MB | 5.6 MB | | @datadog/wasm-js-rewriter | 4.0.1 | 2.85 MB | 3.58 MB | | @datadog/native-metrics | 3.1.1 | 1.02 MB | 1.43 MB | | @opentelemetry/api | 1.8.0 | 1.21 MB | 1.21 MB | | jsonpath-plus | 10.3.0 | 617.18 kB | 1.08 MB | | import-in-the-middle | 1.14.2 | 122.36 kB | 850.93 kB | | lru-cache | 10.4.3 | 804.3 kB | 804.3 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | source-map | 0.7.6 | 185.63 kB | 185.63 kB | | pprof-format | 2.1.0 | 111.69 kB | 111.69 kB | | @datadog/sketches-js | 2.1.1 | 109.9 kB | 109.9 kB | | lodash.sortby | 4.7.0 | 75.76 kB | 75.76 kB | | ignore | 7.0.5 | 63.38 kB | 63.38 kB | | istanbul-lib-coverage | 3.2.2 | 34.37 kB | 34.37 kB | | rfdc | 1.4.1 | 27.15 kB | 27.15 kB | | dc-polyfill | 0.1.10 | 26.73 kB | 26.73 kB | | @isaacs/ttlcache | 1.4.1 | 25.2 kB | 25.2 kB | | tlhunter-sorted-set | 0.1.0 | 24.94 kB | 24.94 kB | | shell-quote | 1.8.3 | 23.74 kB | 23.74 kB | | limiter | 1.1.5 | 23.17 kB | 23.17 kB | | retry | 0.13.1 | 18.85 kB | 18.85 kB | | semifies | 1.0.0 | 15.84 kB | 15.84 kB | | jest-docblock | 29.7.0 | 8.99 kB | 12.76 kB | | crypto-randomuuid | 1.0.0 | 11.18 kB | 11.18 kB | | ttl-set | 1.0.0 | 4.61 kB | 9.69 kB | | mutexify | 1.4.0 | 5.71 kB | 8.74 kB | | path-to-regexp | 0.1.12 | 6.6 kB | 6.6 kB | | koalas | 1.0.2 | 6.47 kB | 6.47 kB | | module-details-from-path | 1.0.4 | 3.96 kB | 3.96 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

[codecov]

Codecov Report

❌ Patch coverage is 28.49162% with 128 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.25%. Comparing base (0502c95) to head (1e9b42b).

Files with missing lines	Patch %	Lines
...-google-cloud-pubsub/src/pubsub-transit-handler.js	14.39%	113 Missing ⚠️
...ckages/datadog-instrumentations/src/body-parser.js	14.28%	12 Missing ⚠️
...ckages/datadog-instrumentations/src/http/server.js	84.21%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6260      +/-   ##
==========================================
- Coverage   84.06%   83.25%   -0.82%     
==========================================
  Files         382      478      +96     
  Lines       17269    20177    +2908     
==========================================
+ Hits        14518    16798    +2280     
- Misses       2751     3379     +628     

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[pr-commenter]

Benchmarks

Benchmark execution time: 2025-08-20 21:22:34

Comparing candidate commit 1e9b42b in PR branch nina.rei/SVLS-7168/gcp-push-pubsub-plugin with baseline commit 0502c95 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 1268 metrics, 55 unstable metrics.

[BridgeAR]

This is quite a big PR, if you like, we could set up a sync call to go through the changes to review the PR :)

[BridgeAR]

I am not sure I understand this change.
I don't think we should ever skip that functionality, since it would also interfere with user's code, if I am not mistaken.