Log with OpenTelemetry, LangGraph, and OpenAI

Learn how to integrate Galileo with OpenTelemetry and OpenInference for comprehensive observability and tracing.

Overview

This guide walks you through running a LangGraph app with:

• OpenTelemetry tracing
• OpenInference semantic conventions
• Galileo’s built-in span processor
• Automatic LangGraph + OpenAI instrumentation

This example application demonstrates how to build a traced, observable LangGraph workflow that processes a user’s question, generates an LLM response, formats it, and sends complete telemetry to Galileo using OpenTelemetry

At a high level, the app:

• Takes a user question
• Validates the input
• Sends the question to OpenAI
• Parses/cleans the LLM response
• Returns a final formatted answer
• Emits detailed traces for every step

The full code example is available in the LangGraph Open Telemetry SDK example.

In this guide you will

• Set up your environment and requirements
• Understanding and running the LangGraph Open Telemetry SDK example
• Run your application with OpenTelemetry

Before you start

Below, you’ll find instructions on the key parts that come into play when using OpenTelemetry for observability.

• Python 3.9+ installed
• A free Galileo account and API key
• An OpenAI API key
• Basic understanding of LangGraph concepts
• Familiarity with OpenTelemetry basics

Set up your environment and requirements

For this how-to guide we’ll assume that you have some familiarity with LangGraph, as well as some familiarity with basic observability principles. To follow this guide pull the code from the LangGraph Open Telemetry SDK example and work in the root of that directory.

1. Install required dependencies

   The corresponding repository ships with a pyproject.toml and so uv is recommended for this project.

   After installing uv, you can create and sync a virtual environment with:

   uv sync
   
2. Set up environment variables

   Create environment file or copy it from the .env.example file

   cp .env.example .env
   
3. Self hosted deployments: Set the OTel endpoint

   Skip this step if you are using Galileo Cloud.

   The OTel endpoint is different from Galileo’s regular API endpoint and is specifically designed to receive telemetry data in the OTLP format.

   If you are using:

   • Galileo Cloud at app.galileo.ai, then you don’t need to provide a custom OTel endpoint. The default endpoint https://api.galileo.ai/otel/traces will be used automatically.

   • A self-hosted Galileo deployment, replace the https://api.galileo.ai/otel/traces endpoint with your deployment URL. The format of this URL is based on your console URL, replacing console with api and appending /otel/traces.

   For example:

   • if your console URL is https://console.galileo.example.com, the OTel endpoint would be https://api.galileo.example.com/otel/traces
   • if your console URL is https://console-galileo.apps.mycompany.com, the OTel endpoint would be https://api-galileo.apps.mycompany.com/otel/traces

   The convention is to store this in the OTEL_EXPORTER_OTLP_ENDPOINT environment variable. For example:

   Python

   os.environ["OTEL_EXPORTER_OTLP_TRACES_ENDPOINT"] = \
       "https://api.galileo.ai/otel/traces"
   

Understanding and running the LangGraph Open Telemetry SDK example

1. Initialize OpenTelemetry and Galileo span processor

   After setting up your environment variables, initialize OpenTelemetry and create the GalileoSpanProcessor. The TracerProvider manages tracers and spans, while the GalileoSpanProcessor is responsible for exporting those spans to Galileo.

   from galileo import otel
   from opentelemetry import trace as trace_api
   from opentelemetry.sdk import trace as trace_sdk
   from opentelemetry.sdk.resources import Resource
   
   # GalileoSpanProcessor (no manual OTLP config required) loads the env vars for 
   # the Galileo API key, Project, and Log stream. Make sure to set them first. 
   galileo_span_processor = otel.GalileoSpanProcessor(
       # Optional parameters if not set, uses env var
       # project=os.environ["GALILEO_PROJECT"], 
       # logstream=os.environ.get("GALILEO_LOG_STREAM"), 
   )
   
   # Resource metadata that will appear in Galileo
   resource = Resource.create({
       "service.name": "LangGraph-OpenTelemetry-Demo",
       "service.version": "1.0.0",
       "deployment.environment": "development",
   })
   
   # Create tracer provider
   tracer_provider = trace_sdk.TracerProvider(resource=resource)
   
   # Attach Galileo processor
   otel.add_galileo_span_processor(tracer_provider, galileo_span_processor)
   
   # Register this provider globally
   trace_api.set_tracer_provider(tracer_provider)
   
2. Apply OpenInference instrumentation

   Enable automatic AI observability by applying OpenInference instrumentors. These automatically capture LLM calls, token usage, and model performance without requiring changes to your existing code.

   from openinference.instrumentation.langchain import LangChainInstrumentor
   from openinference.instrumentation.openai import OpenAIInstrumentor
   
   LangChainInstrumentor().instrument(tracer_provider=tracer_provider)
   OpenAIInstrumentor().instrument(tracer_provider=tracer_provider)
   

   What this enables automatically:

   • LangGraph operations and OpenAI API calls are traced
   • Token usage and model information is captured
   • Performance metrics and errors are recorded
3. Define your LangGraph workflow

   This example app will build a simple LangGraph workflow that:

   • Validates user input with validate_input
   • Calls OpenAI with generate_response
   • Formats the final answer with format_answer

   from typing import TypedDict  
   from langgraph.graph import StateGraph
   from openai import OpenAI
   
   class AgentState(TypedDict, total=False):
       user_input: str  # The user's input question
       llm_response: str  # The raw response from the LLM
       parsed_answer: str  # The processed/cleaned answer
   
   
   # Node 1: Input Validation
   # Validates and prepares the user input for processing
   def validate_input(state: AgentState):
       user_input = state.get("user_input", "")
       print(f"📥 Validating input: '{user_input}'")
   
       return {"user_input": user_input}
   
   
   # Node 2: Generate Response
   # Calls OpenAI to generate a response to the user's question
   # OpenAI instrumentation will automatically create detailed spans
   def generate_response(state: AgentState):
       user_input = state.get("user_input", "")
   
       try:
           print(f"⚙️ Calling OpenAI with: '{user_input}'")
   
           # Make the OpenAI API call - OpenAI instrumentation handles tracing
           response = client.chat.completions.create(
               model="gpt-3.5-turbo",
               messages=[{"role": "user", "content": user_input}],
               max_tokens=300,
               temperature=0.7,
           )
   
           # Extract the response content
           llm_response = response.choices[0].message.content
   
           if not llm_response:
               print("❌ No response from OpenAI")
           else:
               print(f"✓ Received response: '{llm_response[:100]}...'")
   
           return {"llm_response": llm_response}
   
       except Exception as e:
           print(f"❌ Error calling OpenAI: {e}")
           return {"llm_response": f"Error: {str(e)}"}
   
   
   # Node 3: Format Answer
   # Extracts and formats a clean answer from the raw LLM response
   def format_answer(state: AgentState):
       llm_response = state.get("llm_response", "")
   
       # Simple parsing - extract first sentence for a concise answer
       sentences = llm_response.split(". ")
       parsed_answer = sentences[0] if sentences else llm_response
   
       # Clean up the answer
       parsed_answer = parsed_answer.strip()
       if not parsed_answer.endswith(".") and parsed_answer:
           parsed_answer += "."
   
       print(f"✨ Parsed answer: '{parsed_answer}'")
   
       return {"parsed_answer": parsed_answer}
   
4. Build and run the LangGraph application

   Everything is assembled using LangGraph’s StateGraph:

   from langgraph import StateGraph, END
   
   workflow = StateGraph(AgentState)
   
   workflow.add_node("validate_input", validate_input)
   workflow.add_node("generate_response", generate_response)
   workflow.add_node("format_answer", format_answer)
   
   workflow.set_entry_point("validate_input")
   workflow.add_edge("validate_input", "generate_response")
   workflow.add_edge("generate_response", "format_answer")
   workflow.add_edge("format_answer", END)
   
   app = workflow.compile()
   
5. Run the LangGraph application

   Finally, run the LangGraph application to observe the traces in Galileo.

   # Run the app and observe traces in both console and Galileo
   if __name__ == "__main__":
       inputs = {"user_input": "what moons did galileo discover"}
   
       result = app.invoke(AgentState(**inputs))
   
       provider = trace_api.get_tracer_provider()
   
   
       print("\n=== FINAL RESULT ===")
       print(f"Question: {result.get('user_input', 'N/A')}")
       print(f"LLM Response: {result.get('llm_response', 'N/A')}")
       print(f"Parsed Answer: {result.get('parsed_answer', 'N/A')}")
       print("✓ Execution complete - check Galileo for traces in your project/log stream")
   
6. Run the full code example

   Finnaly, run LangGraph Open Telemetry SDK example with:

   uv run python main.py 
   
7. Viewing your traces in Galileo

   Once your application is running with OpenTelemetry configured, you can view your traces in the Galileo dashboard. Navigate to your project and Log stream to see the complete trace graph showing your LangGraph workflow execution.

   

   The trace graph displays:

   • Workflow spans showing the execution flow through your LangGraph nodes
   • LLM call details with token usage and model information
   • Performance metrics including timing and resource utilization
   • Error tracking if any issues occur during execution

Run your application with OpenTelemetry

With OpenTelemetry correctly configured, your application will now automatically capture and send observability data to Galileo with every run. You’ll see complete traces of your LangGraph workflows, detailed LLM call breakdowns with token counts, and performance insights organized by project and Log stream in your Galileo dashboard.

This provides consistent, well-structured logging across all your AI applications without requiring additional code changes, enabling effective monitoring, debugging, and optimization at scale.

OpenInference semantic conventions for LangGraph—Advanced Usage

When running your LangGraph app with OpenInference, Galileo automatically applies semantic conventions to your traces, capturing model information, token usage, and performance metrics without any additional code.

For advanced use cases, you can also manually add custom attributes to enhance your traces with domain-specific information:

1. Span attributes

   # Model information
   span.set_attribute("gen_ai.system", "openai")
   span.set_attribute("gen_ai.request.model", "gpt-4")
   span.set_attribute("gen_ai.request.prompt", user_prompt)
   
   # Response information
   span.set_attribute("gen_ai.response.model", "gpt-4")
   span.set_attribute("gen_ai.response.content", ai_response)
   
   # Token usage
   span.set_attribute("gen_ai.usage.prompt_tokens", 150)
   span.set_attribute("gen_ai.usage.completion_tokens", 75)
   span.set_attribute("gen_ai.usage.total_tokens", 225)
   
2. Events

   # Add events to spans for additional context
   span.add_event("model.loaded", {
       "model.name": "gpt-4",
       "model.size": "1.7T",
       "load.time_ms": 2500
   })
   
   span.add_event("inference.started", {
       "batch.size": 1,
       "max.tokens": 1000
   })
   
   span.add_event("inference.completed", {
       "duration.ms": 1250,
       "tokens.generated": 75
   })
   

Troubleshooting your LangGraph app

Here are some common troubleshooting steps when using OpenTelemetry and OpenInference.

Headers not formatted correctly

Not seeing your OTel traces in Galileo? Double checker your header formatting. OpenTelemetry requires headers in a specific comma-separated string format, not as a dictionary.

# ❌ Wrong - dictionary format won't work with OTel
headers = {"Galileo-API-Key": "your-key", "project": "your-project"}

# ✅ Correct - must be comma-separated string format
os.environ["OTEL_EXPORTER_OTLP_TRACES_HEADERS"] = \
    "Galileo-API-Key=your-key,project=your-project,logstream=default"

Wrong endpoint

# ❌ Wrong - this is the native SDK endpoint
endpoint = "https://api.galileo.ai/v2/otlp"

# ✅ Correct - this is the OTel endpoint
endpoint = "https://api.galileo.ai/otel/traces"

Console URL incorrect

For custom Galileo deployments, replace app.galileo.ai with your deployment URL.

# ❌ Wrong - using default URL for custom deployment
endpoint = "https://api.galileo.ai/otel/traces"

# ✅ Correct - using your custom deployment URL
endpoint = "https://api-your-custom-domain.com/galileo/otel/traces"

Missing LangGraph instrumentation

Not seeing your LangGraph workflow traces? Ensure you’re instrumenting both LangGraph and the underlying LLM providers. LangGraph workflows require instrumentation at multiple levels to capture the complete execution flow.

# ❌ Wrong - only instrumenting OpenAI, missing LangGraph workflow tracing
OpenAIInstrumentor().instrument(tracer_provider=tracer_provider)

# ✅ Correct - instrument both LangGraph workflows and LLM providers
from openinference.instrumentation.langgraph import LangGraphInstrumentor
from openinference.instrumentation.openai import OpenAIInstrumentor

LangGraphInstrumentor().instrument(tracer_provider=tracer_provider)
OpenAIInstrumentor().instrument(tracer_provider=tracer_provider)

Next steps

LangGraph OTel Cookbook

Complete tutorial with working LangGraph example

LangChain Integration

Integrate with LangChain using Galileo callbacks

Custom Metrics

Add custom metrics to track your LangGraph app performance

Experiments

Run experiments on your instrumented LangGraph workflows