INTPYTHON-433 LangGraph longterm memory: MongoDBStore (#121)

Author: caseyclements

.github/scripts/check_diff.py

@@ -2,7 +2,11 @@
 import sys
 from typing import Dict
 
-LIB_DIRS = ["libs/langchain-mongodb", "libs/langgraph-checkpoint-mongodb"]
+LIB_DIRS = [
+    "libs/langchain-mongodb",
+    "libs/langgraph-checkpoint-mongodb",
+    "libs/langgraph-store-mongodb",
+]
 
 if __name__ == "__main__":
     files = sys.argv[1:]  # changed files

libs/langgraph-checkpoint-mongodb/pyproject.toml

@@ -10,14 +10,17 @@ readme = "README.md"
 requires-python = ">=3.9"
 dependencies = [
     "langgraph-checkpoint>=2.0.23,<3.0.0",
+    "langchain-mongodb>=0.6.1",
     "pymongo>=4.10,<4.13",
     "motor>3.6.0",
 ]
 
 [dependency-groups]
 dev = [
     "anyio>=4.4.0",
-    "langchain-core>=0.3.29",
+    "langchain-core>=0.3.55",
+    "langchain-ollama>=0.2.2",
+    "langchain-openai>=0.2.14",
     "langgraph-checkpoint>=2.0.9",
     "pytest-asyncio>=0.21.1",
     "pytest>=7.2.1",

libs/langgraph-checkpoint-mongodb/tests/integration_tests/conftest.py

@@ -0,0 +1,24 @@
+import os
+
+import pytest
+from langchain_core.embeddings import Embeddings
+from langchain_ollama.embeddings import OllamaEmbeddings
+from langchain_openai import OpenAIEmbeddings
+
+
+@pytest.fixture(scope="session")
+def embedding() -> Embeddings:
+    if os.environ.get("OPENAI_API_KEY"):
+        return OpenAIEmbeddings(
+            openai_api_key=os.environ["OPENAI_API_KEY"],  # type: ignore # noqa
+            model="text-embedding-3-small",
+        )
+
+    return OllamaEmbeddings(model="all-minilm:l6-v2")
+
+
+@pytest.fixture(scope="session")
+def dimensions() -> int:
+    if os.environ.get("OPENAI_API_KEY"):
+        return 1536
+    return 384

libs/langgraph-checkpoint-mongodb/uv.lock

@@ -0,0 +1,7 @@
+# Changelog
+
+---
+
+## Changes in version 0.0.1 (2025/05/09)
+
+- Initial release, added support for `MongoDBStore`.

libs/langgraph-store-mongodb/CHANGELOG.md

@@ -0,0 +1,3 @@
+# langraph-store-mongodb
+
+LangGraph long-term memory using MongoDB

libs/langgraph-store-mongodb/README.md

@@ -0,0 +1,40 @@
+set shell := ["bash", "-c"]
+set dotenv-load
+set dotenv-filename := "../../.local_atlas_uri"
+
+# Default target executed when no arguments are given.
+[private]
+default:
+  @just --list
+
+install:
+	uv sync --frozen
+
+[group('test')]
+integration_tests *args="":
+	uv run pytest tests/integration_tests/ {{args}}
+
+[group('test')]
+unit_tests *args="":
+	uv run pytest tests/unit_tests {{args}}
+
+[group('test')]
+tests *args="":
+	uv run pytest {{args}}
+
+[group('test')]
+test_watch filename:
+	uv run ptw --snapshot-update --now . -- -vv {{filename}}
+
+[group('lint')]
+lint:
+	git ls-files -- '*.py' | xargs uv run pre-commit run ruff --files
+	git ls-files -- '*.py' | xargs uv run pre-commit run ruff-format --files
+
+[group('lint')]
+typing:
+	uv run mypy .
+
+[group('lint')]
+codespell:
+	git ls-files -- '*.py' | xargs uv run pre-commit run --hook-stage manual codespell --files

libs/langgraph-store-mongodb/justfile

@@ -0,0 +1,7 @@
+from .base import (
+    MongoDBStore,
+    VectorIndexConfig,
+    create_vector_index_config,
+)
+
+__all__ = ["MongoDBStore", "VectorIndexConfig", "create_vector_index_config"]