refactor: extract common OTLP logic into base classes

[mabdinur]

What does this PR do?

Extracts common OTLP functionality into base classes to eliminate expected code duplication between otel logs and metrics.

Motivation

Prepare for metrics implementation by creating shared infrastructure. Reduces ~400 lines of duplicate code and ensures consistency.

Changes

New Base Classes:

• otlp/otlp_http_exporter_base.js - Shared HTTP export logic (URL parsing, request handling, headers, telemetry)
• otlp/otlp_transformer_base.js - Shared transformation logic (attributes, resources, scopes, serialization)

Refactored Files:

• logs/otlp_http_log_exporter.js - Now extends base class
• logs/otlp_transformer.js - Now extends base class
• test/opentelemetry/logs.spec.js - Updated mocking paths

Benefits

• Single source of truth for HTTP/transformation logic
• Easier to maintain and debug
• Consistent behavior across signal types
• Cleaner code for future metrics implementation (and maybe even otlp trace/profiling support)

Testing

• All existing logs tests pass
• No functionality changes
• No linter errors

Plugin Checklist

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

Additional Notes

[github-actions]

Overall package size

Self size: 12.78 MB
Deduped: 115.39 MB
No deduping: 117.59 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/libdatadog | 0.7.0 | 35.02 MB | 35.02 MB | | @datadog/native-appsec | 10.2.1 | 20.64 MB | 20.65 MB | | @datadog/native-iast-taint-tracking | 4.0.0 | 11.72 MB | 11.73 MB | | @datadog/pprof | 5.11.1 | 9.96 MB | 10.34 MB | | @opentelemetry/core | 1.30.1 | 908.66 kB | 7.16 MB | | protobufjs | 7.5.4 | 2.95 MB | 5.73 MB | | @datadog/wasm-js-rewriter | 4.0.1 | 2.85 MB | 3.58 MB | | @opentelemetry/resources | 1.9.1 | 306.54 kB | 1.74 MB | | @datadog/native-metrics | 3.1.1 | 1.02 MB | 1.43 MB | | @opentelemetry/api-logs | 0.205.0 | 201.51 kB | 1.42 MB | | @opentelemetry/api | 1.9.0 | 1.22 MB | 1.22 MB | | jsonpath-plus | 10.3.0 | 617.18 kB | 1.08 MB | | import-in-the-middle | 1.15.0 | 127.66 kB | 856.24 kB | | lru-cache | 10.4.3 | 804.3 kB | 804.3 kB | | @datadog/openfeature-node-server | 0.1.0-preview.10 | 95.11 kB | 401.46 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | source-map | 0.7.6 | 185.63 kB | 185.63 kB | | pprof-format | 2.2.1 | 163.06 kB | 163.06 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 | | 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 86.60714% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.03%. Comparing base (dc2f39d) to head (97a3cae).
⚠️ Report is 7 commits behind head on master.

Files with missing lines	Patch %	Lines
.../src/opentelemetry/otlp/otlp_http_exporter_base.js	84.48%	9 Missing ⚠️
...ce/src/opentelemetry/otlp/otlp_transformer_base.js	85.36%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6659      +/-   ##
==========================================
- Coverage   84.12%   84.03%   -0.09%     
==========================================
  Files         503      496       -7     
  Lines       21010    20763     -247     
==========================================
- Hits        17674    17448     -226     
+ Misses       3336     3315      -21     

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[pr-commenter]

Benchmarks

Benchmark execution time: 2025-10-16 22:07:25

Comparing candidate commit 97a3cae in PR branch munir/otlp-refactor-base-classes with baseline commit dc2f39d in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 1606 metrics, 64 unstable metrics.

[mabdinur]

9 Missing ⚠️

Base classes are missing test coverage because they are not tested directly. They will have full test coverage in the follow up PR: https://app.codecov.io/gh/DataDog/dd-trace-js/pull/6654/indirect-changes

[khanayan123]

Overall LGTM. Minor NIT: can we create a opentelemetry/exporters subfolder and add otlp_http_exporter_base.js there, same with a opentelemetry/transformers subfolder and add otlp_transformer_base there? we can make maybe even remove the prefix from the two files once it's moved and just call it base?

[mabdinur]

Overall LGTM. Minor NIT: can we create a opentelemetry/exporters subfolder and add otlp_http_exporter_base.js there, same with a opentelemetry/transformers subfolder and add otlp_transformer_base there? we can make maybe even remove the prefix from the two files once it's moved and just call it base?

I get the idea, but I’d keep the current layout for now. Right now we’ve got:

• opentelemetry/logs
• opentelemetry/otlp (which has the base exporter, transformer, and all the proto files)
• .... trace specific files

Keeping all the OTLP serialization logic together in otlp/ makes things a bit easier to manage until we add opentelemetry/metrics in a follow-up. Once that change lands we can break things up into whatever structor makes the most sense. I don't have strong opinions here. Also this branch is also the target for 4 more PRs, so refactoring into new exporters/transformers subfolders now could complicate things and cause extra merge conflicts.