Environment:Truera Trulens LangChain LangGraph Environment
| Knowledge Sources | |
|---|---|
| Domains | Infrastructure, LLM_Frameworks |
| Last Updated | 2026-02-14 08:00 GMT |
Overview
Python 3.9+ environment with LangChain >= 1.0.0, LangGraph >= 0.4.4, and Pydantic 2 for instrumenting LangChain Runnables and LangGraph compiled agents.
Description
This environment provides the framework integration layer for wrapping LangChain Runnables (via `TruChain`) and LangGraph compiled state graphs (via `TruGraph`). `TruGraph` inherits from `TruChain` and combines both instrumentation systems via a `CombinedInstrument` class. LangChain 1.x is required; the codebase has migrated from the pre-1.0 API. Pydantic 2 is mandatory due to LangChain 1.x requirements.
Usage
Use this environment for the RAG Evaluation with LangChain and LangGraph Agent Evaluation workflows. Required whenever using `TruChain` or `TruGraph` to record and evaluate LangChain/LangGraph applications.
System Requirements
| Category | Requirement | Notes |
|---|---|---|
| OS | Any (OS Independent) | Linux, macOS, Windows all supported |
| Python | >= 3.9 | Same as trulens-core |
| Network | Internet access | Required for LLM API calls within chains |
Dependencies
LangChain App (TruChain)
- `trulens-core` >= 2.0.0
- `langchain` >= 1.0.0
- `langchain-core` >= 1.0.0
- `langchain-community` >= 0.3.0
- `pydantic` >= 2.4.2
LangGraph App (TruGraph)
All of the above, plus:
- `langgraph` >= 0.4.4
- `opentelemetry-api` >= 1.23.0
- `opentelemetry-sdk` >= 1.23.0
- `opentelemetry-proto` >= 1.23.0
Credentials
No additional credentials beyond what the underlying LLM provider requires (e.g., `OPENAI_API_KEY` for OpenAI-backed chains).
Quick Install
# Install LangChain integration
pip install trulens-apps-langchain>=2.6.0
# Install LangGraph integration (includes LangChain dependencies)
pip install trulens-apps-langgraph>=2.6.0
Code Evidence
LangChain version constraint from `src/apps/langchain/pyproject.toml:36-39`:
langchain = ">=1.0.0"
langchain-core = ">=1.0.0"
langchain-community = ">=0.3.0"
pydantic = "^2.4.2"
LangGraph version constraint from `src/apps/langgraph/pyproject.toml:39`:
langgraph = ">=0.4.4"
Multiple ImportError handling in `src/apps/langchain/trulens/apps/langchain/tru_chain.py:119-230`:
# Multiple try/except ImportError blocks for optional LangChain components
# Lines 119, 126, 153, 219, 230
Common Errors
| Error Message | Cause | Solution |
|---|---|---|
| `ImportError: langchain` | LangChain not installed | `pip install trulens-apps-langchain` |
| `ModuleNotFoundError: langgraph` | LangGraph not installed | `pip install trulens-apps-langgraph` |
| Pydantic v1 compatibility error | LangChain 1.x requires Pydantic 2 | Upgrade pydantic: `pip install pydantic>=2.4.2` |
Compatibility Notes
- LangChain < 1.0.0: Not supported. See `LANGCHAIN_1X_MIGRATION.md` for migration guidance from pre-1.0 APIs.
- TruGraph inheritance: `TruGraph` inherits from `TruChain`, not directly from `App`. This means LangChain must be installed even when only using LangGraph.
- Async streaming: Async streaming instrumentation for TruGraph has known issues and is disabled (see `tru_graph.py:1542`).