respan-instrumentation-langfuse 1.0.1

OTEL-compliant instrumentation for Langfuse to send traces to Respan

Keywords AI Instrumentation for Langfuse

OTEL-compliant automatic instrumentation for Langfuse that sends all traces to Keywords AI.

✅ Why This Implementation is OTEL-Compliant

This package follows OpenTelemetry best practices:

• ✅ Uses BaseInstrumentor - Standard OTEL instrumentation interface
• ✅ Uses wrapt for safe patching - Reliable, reversible monkey-patching of httpx.Client
• ✅ Single responsibility - Only does instrumentation (HTTP interception), not span processing
• ✅ No import substitution - Use from langfuse import Langfuse normally!
• ✅ Minimal interception - Only redirects Langfuse's HTTP requests to Keywords AI
• ✅ Supports uninstrumentation - Can be cleanly enabled/disabled
• ✅ Compatible with auto-instrumentation - Works with opentelemetry-instrument

Installation

pip install keywordsai-instrumentation-langfuse

Usage

Option 1: Standard OTEL Pattern (Recommended)

# IMPORTANT: Instrument BEFORE importing Langfuse
from keywordsai_instrumentation_langfuse import LangfuseInstrumentor

LangfuseInstrumentor().instrument(api_key="your-keywordsai-api-key")

# Now import and use Langfuse normally - NO code changes needed!
from langfuse import Langfuse, observe

langfuse = Langfuse(
    public_key="your-langfuse-public-key",
    secret_key="your-langfuse-secret-key",
)

@observe()
def my_llm_function(query: str):
    # Your LLM code here
    return f"Response to: {query}"

# All traces automatically go to Keywords AI!
result = my_llm_function("Hello!")
langfuse.flush()

Option 2: Using Environment Variables

export KEYWORDSAI_API_KEY="your-api-key"
# Optionally set custom endpoint:
# export KEYWORDSAI_ENDPOINT="https://custom.endpoint.com/api/v1/traces/ingest"

# Langfuse credentials (Langfuse SDK's own env vars):
export LANGFUSE_PUBLIC_KEY="your-langfuse-public-key"
export LANGFUSE_SECRET_KEY="your-langfuse-secret-key"

# Instrument before importing Langfuse
from keywordsai_instrumentation_langfuse import LangfuseInstrumentor
LangfuseInstrumentor().instrument()

# Use Langfuse normally
from langfuse import Langfuse, observe

Option 3: Zero-Code Auto-Instrumentation

If you have opentelemetry-instrument configured:

export KEYWORDSAI_API_KEY="your-api-key"
# Langfuse credentials can be set via Langfuse's own env vars:
export LANGFUSE_PUBLIC_KEY="your-langfuse-public-key"
export LANGFUSE_SECRET_KEY="your-langfuse-secret-key"

opentelemetry-instrument python your_app.py

Note: LANGFUSE_PUBLIC_KEY and LANGFUSE_SECRET_KEY are Langfuse SDK's own environment variables, not specific to this instrumentation package.

How It Works

The instrumentor patches Langfuse's HTTP client to redirect trace data from Langfuse backend to Keywords AI:

1. You call LangfuseInstrumentor().instrument() before importing Langfuse
2. This patches httpx.Client.send() using wrapt (safe, reversible)
3. You use Langfuse normally with @observe() decorators
4. When Langfuse sends data to its backend, the patch intercepts the HTTP request
5. Data is transformed from Langfuse format to Keywords AI format
6. Request is redirected to Keywords AI API instead

Why patch before import? The HTTP client must be patched before Langfuse creates its client instances. This is standard OTEL instrumentation behavior.

Configuration

Environment Variables

• KEYWORDSAI_API_KEY - Your Keywords AI API key (required)
• KEYWORDSAI_ENDPOINT - Custom endpoint URL (optional, defaults to https://api.keywordsai.co/api/v1/traces/ingest)

Programmatic Configuration

from keywordsai_instrumentation_langfuse import instrument

instrument(
    api_key="your-api-key",
    endpoint="https://custom-endpoint.com/api/v1/traces/ingest",
)

Advanced Usage

Custom Endpoint

from keywordsai_instrumentation_langfuse import LangfuseInstrumentor

LangfuseInstrumentor().instrument(
    api_key="your-api-key",
    endpoint="https://your-instance.com/api/v1/traces/ingest"
)

from langfuse import Langfuse, observe

Disabling Instrumentation

from keywordsai_instrumentation_langfuse import LangfuseInstrumentor

instrumentor = LangfuseInstrumentor()
instrumentor.instrument(api_key="your-key")

# ... use Langfuse ...

# Disable when done
instrumentor.uninstrument()

Troubleshooting

Spans Not Appearing in Keywords AI

1. Check your API key is set correctly
2. Ensure langfuse.flush() is called before program exit
3. Check logs for any error messages
4. Verify network connectivity to Keywords AI API

Import Errors

Make sure all dependencies are installed:

pip install opentelemetry-api opentelemetry-sdk opentelemetry-instrumentation wrapt langfuse requests

Compatibility Issues

• Requires Python 3.8+
• Requires Langfuse SDK v2.0.0+
• Requires OpenTelemetry SDK v1.20.0+

Development

# Install with dev dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Format code
black src/

# Lint
ruff check src/

What Makes This OTEL-Compliant?

1. Uses BaseInstrumentor - Standard OTEL pattern with .instrument() and .uninstrument()
2. Uses wrapt for Patching - Safe, reversible monkey-patching of httpx client
3. Single Responsibility - Only intercepts HTTP requests, doesn't create custom span processors
4. No Import Substitution - Use from langfuse import Langfuse normally
5. Entry Points - Supports opentelemetry-instrument auto-instrumentation

License

Apache 2.0

Support

• Documentation: https://docs.keywordsai.co
• Issues: https://github.com/keywordsai/keywordsai-instrumentation-langfuse/issues
• Email: [e-mail]