Convert some util functions to async (#8035)

synapse/util/metrics.py

@@ -13,14 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import inspect
 import logging
 from functools import wraps
 
 from prometheus_client import Counter
 
-from twisted.internet import defer
-
 from synapse.logging.context import LoggingContext, current_context
 from synapse.metrics import InFlightGauge
 
@@ -62,25 +59,31 @@ in_flight = InFlightGauge(
 
 
 def measure_func(name=None):
+    """
+    Used to decorate an async function with a `Measure` context manager.
+
+    Usage:
+
+    @measure_func()
+    async def foo(...):
+        ...
+
+    Which is analogous to:
+
+    async def foo(...):
+        with Measure(...):
+            ...
+
+    """
+
     def wrapper(func):
         block_name = func.__name__ if name is None else name
 
-        if inspect.iscoroutinefunction(func):
-
-            @wraps(func)
-            async def measured_func(self, *args, **kwargs):
-                with Measure(self.clock, block_name):
-                    r = await func(self, *args, **kwargs)
-                return r
-
-        else:
-
-            @wraps(func)
-            @defer.inlineCallbacks
-            def measured_func(self, *args, **kwargs):
-                with Measure(self.clock, block_name):
-                    r = yield func(self, *args, **kwargs)
-                return r
+        @wraps(func)
+        async def measured_func(self, *args, **kwargs):
+            with Measure(self.clock, block_name):
+                r = await func(self, *args, **kwargs)
+            return r
 
         return measured_func