Add open telemetry tracing

Author: marvinbuss

code/function/wrapper/__init__.py

@@ -1,8 +1,11 @@
 import azure.functions as func
 from fastapp.main import app
+from fastapp.utils import setup_tracer
 from opentelemetry.context import attach, detach
 from opentelemetry.trace.propagation.tracecontext import TraceContextTextMapPropagator
 
+tracer = setup_tracer(__name__)
+
 
 async def main(req: func.HttpRequest, context: func.Context) -> func.HttpResponse:
     # Start distributed tracing
@@ -16,8 +19,11 @@ async def main(req: func.HttpRequest, context: func.Context) -> func.HttpRespons
     token = attach(parent_context)
 
     # Function logic
-    response = await func.AsgiMiddleware(app).handle_async(req, context)
+    try:
+        with tracer.start_as_current_span('wrapper') as span:
+            response = await func.AsgiMiddleware(app).handle_async(req, context)
+    finally:
+        # End distributed tracing
+        detach(token)
 
-    # End distributed tracing
-    detach(token)
     return response