Fix transport attribute not being set

Author: rayz

datadog/dogstatsd/base.py

@@ -534,6 +534,13 @@ def socket(self, new_socket):
             except AttributeError:  # _socket can't have a type if it doesn't have sockopts
                 log.info("Unexpected socket provided with no support for getsockopt")
         self._socket_kind = None
+        if self.socket_path:
+            if self.socket_path.startswith(UNIX_ADDRESS_STREAM_SCHEME):
+                self._transport = "uds-stream"
+            else:
+                self._transport = "uds"
+        else:
+            self._transport = "udp"
         # When the socket is None, we use the UDP optimal payload length
         self._max_payload_size = UDP_OPTIMAL_PAYLOAD_LENGTH
 

tests/unit/dogstatsd/test_statsd.py

@@ -2192,3 +2192,21 @@ def send(self, _):
         statsd.increment("test", 1)
 
         assert statsd.socket is not None
+
+    def test_transport_attribute_present_on_connection_error(self):
+        """
+        Ensure `_transport` attribute is present for telemetry even if the socket is None.
+        """
+        # This test will fail with an AttributeError before the fix.
+        # Use a non-resolvable host to trigger a connection error.
+        statsd = DogStatsd(
+            host='non.existent.host.datadog.internal',
+            telemetry_min_flush_interval=0  # Flush telemetry immediately
+        )
+
+        # This call will attempt to send a metric, fail to create a socket,
+        # and then attempt to send telemetry, which requires `_transport`.
+        statsd.gauge('test.metric', 1)
+
+        assert statsd.socket is None
+        assert statsd._transport is not None