Initial attempt at a scalar callback-based metric to give instantaneous snapshot gauges

1 files changed, 10 insertions, 1 deletions

diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index d5c30bbe41..d7584fc0bc 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .metric import CounterMetric, CacheCounterMetric
+from .metric import CounterMetric, CallbackMetric, CacheCounterMetric
 
 
 # We'll keep all the available metrics in a single toplevel dict, one shared
@@ -43,6 +43,15 @@ class Metrics(object):
 
         return metric
 
+    def register_callback(self, name, callback, *args, **kwargs):
+        full_name = "%s.%s" % (self.name_prefix, name)
+
+        metric = CallbackMetric(full_name, *args, callback=callback, **kwargs)
+
+        self._register(metric)
+
+        return metric
+
     def register_cachecounter(self, name, *args, **kwargs):
         full_name = "%s.%s" % (self.name_prefix, name)