fix(opentelemetry-instrumentation-asgi): Correct http.url attribute g…

…eneration (#2477)

CHANGELOG.md

@@ -15,6 +15,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#2612](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2612))
 - `opentelemetry-instrumentation-system-metrics` Permit to use psutil 6.0+.
   ([#2630](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2630))
+- `opentelemetry-instrumentation-asgi` Fix generation of `http.target` and `http.url` attributes for ASGI apps
+  using sub apps
+  ([#2477](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2477))
+
 
 ### Added
 

instrumentation/opentelemetry-instrumentation-asgi/src/opentelemetry/instrumentation/asgi/__init__.py

@@ -367,7 +367,13 @@ def get_host_port_url_tuple(scope):
     server = scope.get("server") or ["0.0.0.0", 80]
     port = server[1]
     server_host = server[0] + (":" + str(port) if str(port) != "80" else "")
-    full_path = scope.get("root_path", "") + scope.get("path", "")
+    # using the scope path is enough, see:
+    # - https://asgi.readthedocs.io/en/latest/specs/www.html#http-connection-scope (see: root_path and path)
+    # - https://asgi.readthedocs.io/en/latest/specs/www.html#wsgi-compatibility (see: PATH_INFO)
+    #       PATH_INFO can be derived by stripping root_path from path
+    #       -> that means that the path should contain the root_path already, so prefixing it again is not necessary
+    # - https://wsgi.readthedocs.io/en/latest/definitions.html#envvar-PATH_INFO
+    full_path = scope.get("path", "")
     http_url = scope.get("scheme", "http") + "://" + server_host + full_path
     return server_host, port, http_url