Expand description
OpenTelemetry integration for Langfuse.
This crate provides OpenTelemetry components and utilities for integrating with Langfuse, enabling comprehensive observability for LLM applications.
For detailed information about OpenTelemetry support in Langfuse, see the official documentation.
§Quick Start
use opentelemetry_langfuse::exporter_from_env;
use opentelemetry_sdk::trace::SdkTracerProvider;
use opentelemetry_sdk::Resource;
use opentelemetry::KeyValue;
use opentelemetry::global;
// Create the Langfuse exporter from environment variables
// Requires: LANGFUSE_HOST, LANGFUSE_PUBLIC_KEY, LANGFUSE_SECRET_KEY
let exporter = exporter_from_env()?;
// Create your tracer provider with the Langfuse exporter
let provider = SdkTracerProvider::builder()
.with_batch_exporter(exporter)
.with_resource(Resource::builder().with_attributes(vec![
KeyValue::new("service.name", "my-service"),
]).build())
.build();
// Set as global provider
global::set_tracer_provider(provider);
// Use the tracer
let tracer = global::tracer("my-tracer");
// ... your tracing code here ...
// Provider will be shutdown when it goes out of scope§Components
§Exporter
- Configured OTLP/HTTP exporter for sending traces to Langfuse
- Automatic authentication header setup
- Environment variable configuration support (both Langfuse and OTEL standards)
- Builder pattern for custom configuration
§Environment Variables
This crate supports both Langfuse-specific and standard OpenTelemetry environment variables for configuration. You can choose the configuration style that best fits your needs:
§Langfuse-Specific Variables
Use these when working directly with Langfuse:
LANGFUSE_HOST: Base URL of your Langfuse instance (defaults tohttps://cloud.langfuse.com)LANGFUSE_PUBLIC_KEY: Your Langfuse public keyLANGFUSE_SECRET_KEY: Your Langfuse secret key
Example:
export LANGFUSE_HOST="https://cloud.langfuse.com"
export LANGFUSE_PUBLIC_KEY="pk-lf-..."
export LANGFUSE_SECRET_KEY="sk-lf-..."Use exporter_from_langfuse_env() to create an exporter using only these variables.
§Standard OpenTelemetry Variables
Following the OpenTelemetry Protocol Exporter specification:
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT: Direct endpoint for tracesOTEL_EXPORTER_OTLP_ENDPOINT: Base endpoint (will append/v1/traces)OTEL_EXPORTER_OTLP_TRACES_HEADERS: Headers for traces endpointOTEL_EXPORTER_OTLP_HEADERS: General headers
Example:
export OTEL_EXPORTER_OTLP_TRACES_ENDPOINT="https://cloud.langfuse.com/api/public/otel/v1/traces"
export OTEL_EXPORTER_OTLP_TRACES_HEADERS="Authorization=Basic <base64_encoded_credentials>"Use exporter_from_otel_env() to create an exporter using only these variables.
§Automatic Fallback
The exporter_from_env() function provides automatic fallback between both styles,
with Langfuse-specific variables taking precedence:
- First checks for Langfuse-specific variables
- Falls back to standard OTEL variables if Langfuse variables are not found
- Uses sensible defaults where applicable
This allows for flexible configuration in different deployment scenarios.
Re-exports§
pub use auth::build_auth_header;pub use auth::build_auth_header_from_env;pub use endpoint::build_otlp_endpoint;pub use endpoint::build_otlp_endpoint_from_env;pub use error::Error;pub use error::Result;pub use exporter::exporter;pub use exporter::exporter_from_env;pub use exporter::exporter_from_langfuse_env;pub use exporter::exporter_from_otel_env;pub use exporter::ExporterBuilder;