Middleware

middleware

Middleware for making it easier to do distributed tracing.

TracingMiddleware

Middleware for propagating distributed tracing context using LangSmith.

This middleware checks for the 'langsmith-trace' header and propagates the tracing context if present. It does not start new traces by default.

Designed to work with ASGI applications.

ATTRIBUTE	DESCRIPTION
app	The ASGI application being wrapped.

METHOD	DESCRIPTION
__init__	Initialize the middleware.
__call__	Handle incoming requests and propagate tracing context if applicable.

__init__

__init__(app)

Initialize the middleware.

__call__ async

__call__(scope: dict, receive, send)

Handle incoming requests and propagate tracing context if applicable.

PARAMETER	DESCRIPTION
scope	A dict containing ASGI connection scope. TYPE: dict
receive	An awaitable callable for receiving ASGI events. TYPE: callable
send	An awaitable callable for sending ASGI events. TYPE: callable

If the request is HTTP and contains the 'langsmith-trace' header, it propagates the tracing context before calling the wrapped application.

Otherwise, it calls the application directly without modifying the context.