__init__.py

import azure.functions as func
from fastapp.main import app, lifespan_sync
from fastapp.utils import setup_tracer
from opentelemetry.trace.propagation.tracecontext import TraceContextTextMapPropagator

lifespan_sync(app=app)
tracer = setup_tracer(__name__)


async def main(req: func.HttpRequest, context: func.Context) -> func.HttpResponse:
    # Start distributed tracing
    functions_current_context = {
        "traceparent": context.trace_context.Traceparent,
        "tracestate": context.trace_context.Tracestate,
    }
    parent_context = TraceContextTextMapPropagator().extract(
        carrier=functions_current_context
    )

    # Function logic
    with tracer.start_as_current_span("wrapper", context=parent_context) as span:
        response = await func.AsgiMiddleware(app).handle_async(
            req=req, context=parent_context
        )

    return response