Add HTTP user-agent in WSGI instrumentation (open-telemetry#964)

Author: jan25

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

@@ -117,6 +117,10 @@ def collect_request_attributes(environ):
     if remote_host and remote_host != remote_addr:
         result["net.peer.name"] = remote_host
 
+    user_agent = environ.get("HTTP_USER_AGENT")
+    if user_agent is not None and len(user_agent) > 0:
+        result["http.user_agent"] = user_agent
+
     setifnotnone(result, "net.peer.port", environ.get("REMOTE_PORT"))
     flavor = environ.get("SERVER_PROTOCOL", "")
     if flavor.upper().startswith(_HTTP_VERSION_PREFIX):

instrumentation/opentelemetry-instrumentation-wsgi/tests/test_wsgi_middleware.py

@@ -313,6 +313,14 @@ def test_request_attributes_with_full_request_uri(self):
             expected.items(),
         )
 
+    def test_http_user_agent_attribute(self):
+        self.environ["HTTP_USER_AGENT"] = "test-useragent"
+        expected = {"http.user_agent": "test-useragent"}
+        self.assertGreaterEqual(
+            otel_wsgi.collect_request_attributes(self.environ).items(),
+            expected.items(),
+        )
+
     def test_response_attributes(self):
         otel_wsgi.add_response_attributes(self.span, "404 Not Found", {})
         expected = (