feat(langgraph): submit spans from langgraph to APM and LLMObs (#11730)

This PR adds a simple integration and corresponding LLMObs plugin for
the LangGraph framework.

### Enablement

For both APM and LLMObs, this integration is disabled by default, and
only enabled with `DD_TRACE_LANGGRAPH_ENABLED=true` or
`patch(langgraph=True)`, along with `_DD_TRACE_LANGGRAPH_ENABLED=true`,
due to its experimental nature.

### APM Tracing

The APM integration adds basic tracing for LangGraph `Pregel` graph
invocations, as well as the execution of each node/step in the graph
(traced as `RunnableSeq`).

### LLM Observability Plugin

The LLMObs plugin submits the traces to LLM Observability.

#### Graph Invocation/Streaming Output Tagging

Because we patch the `(a)stream` method for both streams and
`(a)invoke`, since they rely on `(a)stream` under the hood, we are bound
to the yields from the stream. The object shape and value depend on the
`stream_mode` passed in to the stream function. For `invoke`, it
defaults to `"values"`, which is perfect for our use case. However, if
one were to call `stream` directly, and either pass in nothing or
something like `stream_mode=["updates", "debug"]`, the output we would
have for the graph span would appear as:

```
{
  "type": "task_result",
  "timestamp": "2025-01-03T14:45:26.087608+00:00",
  "step": "3",
  "payload": {
    "id": "399cfe0a-aefd-f67c-6909-fcea80ef508b",
    "name": "e",
    "error": "None",
    "result": [
      "('a_list', ['e'])"
    ],
    "interrupts": []
  }
}
```

This is a known limitation for now, and a more thought-out solution for
either adding on `"values"` to `stream_mode` and omitting their yields
if it wasn't already present, or having some kind of clever joining, can
be added in a later PR or by feature request.

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

---------

Co-authored-by: Yun Kim <[email protected]>
Co-authored-by: Yun Kim <[email protected]>

.github/CODEOWNERS

@@ -145,6 +145,8 @@ ddtrace/contrib/internal/google_generativeai            @DataDog/ml-observabilit
 ddtrace/contrib/google_generativeai                     @DataDog/ml-observability
 ddtrace/contrib/internal/vertexai                       @DataDog/ml-observability
 ddtrace/contrib/vertexai                                @DataDog/ml-observability
+ddtrace/contrib/langgraph                               @DataDog/ml-observability
+ddtrace/contrib/internal/langgraph                      @DataDog/ml-observability
 tests/llmobs                                            @DataDog/ml-observability
 tests/contrib/openai                                    @DataDog/ml-observability
 tests/contrib/langchain                                 @DataDog/ml-observability
@@ -154,6 +156,7 @@ tests/contrib/botocore/bedrock_cassettes                @DataDog/ml-observabilit
 tests/contrib/anthropic                                 @DataDog/ml-observability
 tests/contrib/google_generativeai                       @DataDog/ml-observability
 tests/contrib/vertexai                                  @DataDog/ml-observability
+tests/contrib/langgraph                                 @DataDog/ml-observability
 .gitlab/tests/llmobs.yml                                @DataDog/ml-observability
 
 # Remote Config

.riot/requirements/115283d.txt

@@ -0,0 +1,42 @@
+#
+# This file is autogenerated by pip-compile with Python 3.12
+# by the following command:
+#
+#    pip-compile --allow-unsafe --no-annotate .riot/requirements/115283d.in
+#
+anyio==4.7.0
+attrs==24.3.0
+certifi==2024.12.14
+charset-normalizer==3.4.1
+coverage[toml]==7.6.10
+h11==0.14.0
+httpcore==1.0.7
+httpx==0.28.1
+hypothesis==6.45.0
+idna==3.10
+iniconfig==2.0.0
+jsonpatch==1.33
+jsonpointer==3.0.0
+langchain-core==0.3.28
+langgraph==0.2.60
+langgraph-checkpoint==2.0.9
+langgraph-sdk==0.1.48
+langsmith==0.2.6
+mock==5.1.0
+msgpack==1.1.0
+opentracing==2.4.0
+orjson==3.10.12
+packaging==24.2
+pluggy==1.5.0
+pytest==8.3.4
+pytest-asyncio==0.25.0
+pytest-cov==6.0.0
+pytest-mock==3.14.0
+pyyaml==6.0.2
+requests==2.32.3
+requests-toolbelt==1.0.0
+sniffio==1.3.1
+sortedcontainers==2.4.0
+tenacity==9.0.0
+typing-extensions==4.12.2
+urllib3==2.3.0

.riot/requirements/18551a1.txt

@@ -0,0 +1,45 @@
+#
+# This file is autogenerated by pip-compile with Python 3.13
+# by the following command:
+#
+#    pip-compile --allow-unsafe --no-annotate .riot/requirements/18551a1.in
+#
+annotated-types==0.7.0
+anyio==4.8.0
+attrs==24.3.0
+certifi==2024.12.14
+charset-normalizer==3.4.1
+coverage[toml]==7.6.10
+h11==0.14.0
+httpcore==1.0.7
+httpx==0.28.1
+hypothesis==6.45.0
+idna==3.10
+iniconfig==2.0.0
+jsonpatch==1.33
+jsonpointer==3.0.0
+langchain-core==0.3.29
+langgraph==0.2.61
+langgraph-checkpoint==2.0.9
+langgraph-sdk==0.1.48
+langsmith==0.2.10
+mock==5.1.0
+msgpack==1.1.0
+opentracing==2.4.0
+orjson==3.10.14
+packaging==24.2
+pluggy==1.5.0
+pydantic==2.10.5
+pydantic-core==2.27.2
+pytest==8.3.4
+pytest-asyncio==0.25.2
+pytest-cov==6.0.0
+pytest-mock==3.14.0
+pyyaml==6.0.2
+requests==2.32.3
+requests-toolbelt==1.0.0
+sniffio==1.3.1
+sortedcontainers==2.4.0
+tenacity==9.0.0
+typing-extensions==4.12.2
+urllib3==2.3.0

.riot/requirements/2bd0151.txt

@@ -0,0 +1,45 @@
+#
+# This file is autogenerated by pip-compile with Python 3.11
+# by the following command:
+#
+#    pip-compile --allow-unsafe --no-annotate --resolver=backtracking .riot/requirements/2bd0151.in
+#
+annotated-types==0.7.0
+anyio==4.7.0
+attrs==24.3.0
+certifi==2024.12.14
+charset-normalizer==3.4.0
+coverage[toml]==7.6.9
+h11==0.14.0
+httpcore==1.0.7
+httpx==0.28.1
+hypothesis==6.45.0
+idna==3.10
+iniconfig==2.0.0
+jsonpatch==1.33
+jsonpointer==3.0.0
+langchain-core==0.3.28
+langgraph==0.2.60
+langgraph-checkpoint==2.0.9
+langgraph-sdk==0.1.48
+langsmith==0.2.4
+mock==5.1.0
+msgpack==1.1.0
+opentracing==2.4.0
+orjson==3.10.12
+packaging==24.2
+pluggy==1.5.0
+pydantic==2.10.4
+pydantic-core==2.27.2
+pytest==8.3.4
+pytest-asyncio==0.25.0
+pytest-cov==6.0.0
+pytest-mock==3.14.0
+pyyaml==6.0.2
+requests==2.32.3
+requests-toolbelt==1.0.0
+sniffio==1.3.1
+sortedcontainers==2.4.0
+tenacity==9.0.0
+typing-extensions==4.12.2
+urllib3==2.3.0

.riot/requirements/2e4fbd3.txt

@@ -0,0 +1,47 @@
+#
+# This file is autogenerated by pip-compile with Python 3.9
+# by the following command:
+#
+#    pip-compile --allow-unsafe --no-annotate --resolver=backtracking .riot/requirements/2e4fbd3.in
+#
+annotated-types==0.7.0
+anyio==4.7.0
+attrs==24.3.0
+certifi==2024.12.14
+charset-normalizer==3.4.1
+coverage[toml]==7.6.10
+exceptiongroup==1.2.2
+h11==0.14.0
+httpcore==1.0.7
+httpx==0.28.1
+hypothesis==6.45.0
+idna==3.10
+iniconfig==2.0.0
+jsonpatch==1.33
+jsonpointer==3.0.0
+langchain-core==0.3.28
+langgraph==0.2.60
+langgraph-checkpoint==2.0.9
+langgraph-sdk==0.1.48
+langsmith==0.2.6
+mock==5.1.0
+msgpack==1.1.0
+opentracing==2.4.0
+orjson==3.10.12
+packaging==24.2
+pluggy==1.5.0
+pydantic==2.10.4
+pydantic-core==2.27.2
+pytest==8.3.4
+pytest-asyncio==0.25.0
+pytest-cov==6.0.0
+pytest-mock==3.14.0
+pyyaml==6.0.2
+requests==2.32.3
+requests-toolbelt==1.0.0
+sniffio==1.3.1
+sortedcontainers==2.4.0
+tenacity==9.0.0
+tomli==2.2.1
+typing-extensions==4.12.2
+urllib3==2.3.0

.riot/requirements/7dd4bcd.txt

@@ -0,0 +1,47 @@
+#
+# This file is autogenerated by pip-compile with Python 3.10
+# by the following command:
+#
+#    pip-compile --allow-unsafe --no-annotate .riot/requirements/7dd4bcd.in
+#
+annotated-types==0.7.0
+anyio==4.7.0
+attrs==24.3.0
+certifi==2024.12.14
+charset-normalizer==3.4.1
+coverage[toml]==7.6.10
+exceptiongroup==1.2.2
+h11==0.14.0
+httpcore==1.0.7
+httpx==0.28.1
+hypothesis==6.45.0
+idna==3.10
+iniconfig==2.0.0
+jsonpatch==1.33
+jsonpointer==3.0.0
+langchain-core==0.3.28
+langgraph==0.2.60
+langgraph-checkpoint==2.0.9
+langgraph-sdk==0.1.48
+langsmith==0.2.6
+mock==5.1.0
+msgpack==1.1.0
+opentracing==2.4.0
+orjson==3.10.12
+packaging==24.2
+pluggy==1.5.0
+pydantic==2.10.4
+pydantic-core==2.27.2
+pytest==8.3.4
+pytest-asyncio==0.25.0
+pytest-cov==6.0.0
+pytest-mock==3.14.0
+pyyaml==6.0.2
+requests==2.32.3
+requests-toolbelt==1.0.0
+sniffio==1.3.1
+sortedcontainers==2.4.0
+tenacity==9.0.0
+tomli==2.2.1
+typing-extensions==4.12.2
+urllib3==2.3.0

ddtrace/_monkey.py

@@ -49,6 +49,7 @@
     "grpc": True,
     "httpx": True,
     "kafka": True,
+    "langgraph": False,
     "mongoengine": True,
     "mysql": True,
     "mysqldb": True,
@@ -149,6 +150,10 @@
     "httplib": ("http.client",),
     "kafka": ("confluent_kafka",),
     "google_generativeai": ("google.generativeai",),
+    "langgraph": (
+        "langgraph",
+        "langgraph.graph",
+    ),
 }