[MLOB-1858] feat(llmobs): langchain submits llmobs span events

[sabrenner]

What does this PR do?

Adds an additional LangChainLLMObs plugin to handle sending LLMObs span events for the LangChain integration. This plugin is registered as part of the existing LangChain plugin, but is not enabled when LLMObs is not enabled.

Motivation

Furthering auto-instrumentation for the LLMObs Node.js SDK. This integration will be expanded upon to be in parity with the Python SDK in future PRs.

[github-actions]

Overall package size

Self size: 8.16 MB
Deduped: 94.66 MB
No deduping: 95 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/libdatadog | 0.2.2 | 29.27 MB | 29.27 MB | | @datadog/native-appsec | 8.3.0 | 19.37 MB | 19.38 MB | | @datadog/native-iast-taint-tracking | 3.2.0 | 13.9 MB | 13.91 MB | | @datadog/pprof | 5.4.1 | 9.76 MB | 10.13 MB | | protobufjs | 7.2.5 | 2.77 MB | 5.16 MB | | @datadog/native-iast-rewriter | 2.5.0 | 2.51 MB | 2.65 MB | | @opentelemetry/core | 1.14.0 | 872.87 kB | 1.47 MB | | @datadog/native-metrics | 3.0.1 | 1.06 MB | 1.46 MB | | @opentelemetry/api | 1.8.0 | 1.21 MB | 1.21 MB | | import-in-the-middle | 1.11.2 | 112.74 kB | 826.22 kB | | msgpack-lite | 0.1.26 | 201.16 kB | 281.59 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | lru-cache | 7.18.3 | 133.92 kB | 133.92 kB | | pprof-format | 2.1.0 | 111.69 kB | 111.69 kB | | @datadog/sketches-js | 2.1.0 | 109.9 kB | 109.9 kB | | semver | 7.6.3 | 95.82 kB | 95.82 kB | | lodash.sortby | 4.7.0 | 75.76 kB | 75.76 kB | | ignore | 5.3.1 | 51.46 kB | 51.46 kB | | int64-buffer | 0.1.10 | 49.18 kB | 49.18 kB | | shell-quote | 1.8.1 | 44.96 kB | 44.96 kB | | istanbul-lib-coverage | 3.2.0 | 29.34 kB | 29.34 kB | | rfdc | 1.3.1 | 25.21 kB | 25.21 kB | | @isaacs/ttlcache | 1.4.1 | 25.2 kB | 25.2 kB | | tlhunter-sorted-set | 0.1.0 | 24.94 kB | 24.94 kB | | limiter | 1.1.5 | 23.17 kB | 23.17 kB | | dc-polyfill | 0.1.4 | 23.1 kB | 23.1 kB | | retry | 0.13.1 | 18.85 kB | 18.85 kB | | jest-docblock | 29.7.0 | 8.99 kB | 12.76 kB | | crypto-randomuuid | 1.0.0 | 11.18 kB | 11.18 kB | | koalas | 1.0.2 | 6.47 kB | 6.47 kB | | path-to-regexp | 0.1.10 | 6.38 kB | 6.38 kB | | module-details-from-path | 1.0.3 | 4.47 kB | 4.47 kB |

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

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-11-26 15:24:35

Comparing candidate commit a14f2f2 in PR branch sabrenner/llmobs-langchain with baseline commit d3b9b3a in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 261 metrics, 5 unstable metrics.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.

Project coverage is 62.20%. Comparing base (c8ab3e4) to head (fbfa26e).
Report is 8 commits behind head on master.

Files with missing lines	Patch %	Lines
packages/dd-trace/src/llmobs/tagger.js	0.00%	3 Missing ⚠️
packages/dd-trace/src/llmobs/util.js	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4923      +/-   ##
==========================================
- Coverage   66.51%   62.20%   -4.32%     
==========================================
  Files         143      281     +138     
  Lines        4784    13125    +8341     
==========================================
+ Hits         3182     8164    +4982     
- Misses       1602     4961    +3359     

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