Revert "Fix LaterGauge metrics to collect from all servers (#18751)"

This reverts commit 076db0a.

Author: devonh

changelog.d/18751.misc

@@ -37,7 +37,6 @@
 """
 
 import logging
-from enum import Enum
 from typing import (
     TYPE_CHECKING,
     Dict,
@@ -68,25 +67,6 @@
 logger = logging.getLogger(__name__)
 
 
-class QueueNames(str, Enum):
-    PRESENCE_MAP = "presence_map"
-    KEYED_EDU = "keyed_edu"
-    KEYED_EDU_CHANGED = "keyed_edu_changed"
-    EDUS = "edus"
-    POS_TIME = "pos_time"
-    PRESENCE_DESTINATIONS = "presence_destinations"
-
-
-queue_name_to_gauge_map: Dict[QueueNames, LaterGauge] = {}
-
-for queue_name in QueueNames:
-    queue_name_to_gauge_map[queue_name] = LaterGauge(
-        name=f"synapse_federation_send_queue_{queue_name.value}_size",
-        desc="",
-        labelnames=[SERVER_NAME_LABEL],
-    )
-
-
 class FederationRemoteSendQueue(AbstractFederationSender):
     """A drop in replacement for FederationSender"""
 
@@ -131,15 +111,23 @@ def __init__(self, hs: "HomeServer"):
         # we make a new function, so we need to make a new function so the inner
         # lambda binds to the queue rather than to the name of the queue which
         # changes. ARGH.
-        def register(queue_name: QueueNames, queue: Sized) -> None:
-            queue_name_to_gauge_map[queue_name].register_hook(
-                lambda: {(self.server_name,): len(queue)}
+        def register(name: str, queue: Sized) -> None:
+            LaterGauge(
+                name="synapse_federation_send_queue_%s_size" % (queue_name,),
+                desc="",
+                labelnames=[SERVER_NAME_LABEL],
+                caller=lambda: {(self.server_name,): len(queue)},
             )
 
-        for queue_name in QueueNames:
-            queue = getattr(self, queue_name.value)
-            assert isinstance(queue, Sized)
-            register(queue_name, queue=queue)
+        for queue_name in [
+            "presence_map",
+            "keyed_edu",
+            "keyed_edu_changed",
+            "edus",
+            "pos_time",
+            "presence_destinations",
+        ]:
+            register(queue_name, getattr(self, queue_name))
 
         self.clock.looping_call(self._clear_queue, 30 * 1000)
 

synapse/federation/send_queue.py

@@ -199,24 +199,6 @@
     labelnames=[SERVER_NAME_LABEL],
 )
 
-transaction_queue_pending_destinations_gauge = LaterGauge(
-    name="synapse_federation_transaction_queue_pending_destinations",
-    desc="",
-    labelnames=[SERVER_NAME_LABEL],
-)
-
-transaction_queue_pending_pdus_gauge = LaterGauge(
-    name="synapse_federation_transaction_queue_pending_pdus",
-    desc="",
-    labelnames=[SERVER_NAME_LABEL],
-)
-
-transaction_queue_pending_edus_gauge = LaterGauge(
-    name="synapse_federation_transaction_queue_pending_edus",
-    desc="",
-    labelnames=[SERVER_NAME_LABEL],
-)
-
 # Time (in s) to wait before trying to wake up destinations that have
 # catch-up outstanding.
 # Please note that rate limiting still applies, so while the loop is
@@ -416,28 +398,38 @@ def __init__(self, hs: "HomeServer"):
         # map from destination to PerDestinationQueue
         self._per_destination_queues: Dict[str, PerDestinationQueue] = {}
 
-        transaction_queue_pending_destinations_gauge.register_hook(
-            lambda: {
+        LaterGauge(
+            name="synapse_federation_transaction_queue_pending_destinations",
+            desc="",
+            labelnames=[SERVER_NAME_LABEL],
+            caller=lambda: {
                 (self.server_name,): sum(
                     1
                     for d in self._per_destination_queues.values()
                     if d.transmission_loop_running
                 )
-            }
+            },
         )
-        transaction_queue_pending_pdus_gauge.register_hook(
-            lambda: {
+
+        LaterGauge(
+            name="synapse_federation_transaction_queue_pending_pdus",
+            desc="",
+            labelnames=[SERVER_NAME_LABEL],
+            caller=lambda: {
                 (self.server_name,): sum(
                     d.pending_pdu_count() for d in self._per_destination_queues.values()
                 )
-            }
+            },
         )
-        transaction_queue_pending_edus_gauge.register_hook(
-            lambda: {
+        LaterGauge(
+            name="synapse_federation_transaction_queue_pending_edus",
+            desc="",
+            labelnames=[SERVER_NAME_LABEL],
+            caller=lambda: {
                 (self.server_name,): sum(
                     d.pending_edu_count() for d in self._per_destination_queues.values()
                 )
-            }
+            },
         )
 
         self._is_processing = False

synapse/federation/sender/__init__.py

@@ -173,18 +173,6 @@
     labelnames=["locality", "from", "to", SERVER_NAME_LABEL],
 )
 
-presence_user_to_current_state_size_gauge = LaterGauge(
-    name="synapse_handlers_presence_user_to_current_state_size",
-    desc="",
-    labelnames=[SERVER_NAME_LABEL],
-)
-
-presence_wheel_timer_size_gauge = LaterGauge(
-    name="synapse_handlers_presence_wheel_timer_size",
-    desc="",
-    labelnames=[SERVER_NAME_LABEL],
-)
-
 # If a user was last active in the last LAST_ACTIVE_GRANULARITY, consider them
 # "currently_active"
 LAST_ACTIVE_GRANULARITY = 60 * 1000
@@ -791,8 +779,11 @@ def __init__(self, hs: "HomeServer"):
             EduTypes.PRESENCE, self.incoming_presence
         )
 
-        presence_user_to_current_state_size_gauge.register_hook(
-            lambda: {(self.server_name,): len(self.user_to_current_state)}
+        LaterGauge(
+            name="synapse_handlers_presence_user_to_current_state_size",
+            desc="",
+            labelnames=[SERVER_NAME_LABEL],
+            caller=lambda: {(self.server_name,): len(self.user_to_current_state)},
         )
 
         # The per-device presence state, maps user to devices to per-device presence state.
@@ -891,8 +882,11 @@ def __init__(self, hs: "HomeServer"):
                 60 * 1000,
             )
 
-        presence_wheel_timer_size_gauge.register_hook(
-            lambda: {(self.server_name,): len(self.wheel_timer)}
+        LaterGauge(
+            name="synapse_handlers_presence_wheel_timer_size",
+            desc="",
+            labelnames=[SERVER_NAME_LABEL],
+            caller=lambda: {(self.server_name,): len(self.wheel_timer)},
         )
 
         # Used to handle sending of presence to newly joined users/servers

synapse/handlers/presence.py

@@ -164,12 +164,12 @@ def _get_in_flight_counts() -> Mapping[Tuple[str, ...], int]:
     return counts
 
 
-in_flight_requests = LaterGauge(
+LaterGauge(
     name="synapse_http_server_in_flight_requests_count",
     desc="",
     labelnames=["method", "servlet", SERVER_NAME_LABEL],
+    caller=_get_in_flight_counts,
 )
-in_flight_requests.register_hook(_get_in_flight_counts)
 
 
 class RequestMetrics:

synapse/http/request_metrics.py

@@ -31,7 +31,6 @@
     Dict,
     Generic,
     Iterable,
-    List,
     Mapping,
     Optional,
     Sequence,
@@ -74,6 +73,8 @@
 
 METRICS_PREFIX = "/_synapse/metrics"
 
+all_gauges: Dict[str, Collector] = {}
+
 HAVE_PROC_SELF_STAT = os.path.exists("/proc/self/stat")
 
 SERVER_NAME_LABEL = "server_name"
@@ -162,47 +163,42 @@ class LaterGauge(Collector):
     name: str
     desc: str
     labelnames: Optional[StrSequence] = attr.ib(hash=False)
-    # List of callbacks: each callback should either return a value (if there are no
-    # labels for this metric), or dict mapping from a label tuple to a value
-    _hooks: List[
-        Callable[
-            [], Union[Mapping[Tuple[str, ...], Union[int, float]], Union[int, float]]
-        ]
-    ] = attr.ib(factory=list, hash=False)
+    # callback: should either return a value (if there are no labels for this metric),
+    # or dict mapping from a label tuple to a value
+    caller: Callable[
+        [], Union[Mapping[Tuple[str, ...], Union[int, float]], Union[int, float]]
+    ]
 
     def collect(self) -> Iterable[Metric]:
         # The decision to add `SERVER_NAME_LABEL` is from the `LaterGauge` usage itself
         # (we don't enforce it here, one level up).
         g = GaugeMetricFamily(self.name, self.desc, labels=self.labelnames)  # type: ignore[missing-server-name-label]
 
-        for hook in self._hooks:
-            try:
-                hook_result = hook()
-            except Exception:
-                logger.exception(
-                    "Exception running callback for LaterGauge(%s)", self.name
-                )
-                yield g
-                return
-
-            if isinstance(hook_result, (int, float)):
-                g.add_metric([], hook_result)
-            else:
-                for k, v in hook_result.items():
-                    g.add_metric(k, v)
-
+        try:
+            calls = self.caller()
+        except Exception:
+            logger.exception("Exception running callback for LaterGauge(%s)", self.name)
             yield g
+            return
 
-    def register_hook(
-        self,
-        hook: Callable[
-            [], Union[Mapping[Tuple[str, ...], Union[int, float]], Union[int, float]]
-        ],
-    ) -> None:
-        self._hooks.append(hook)
+        if isinstance(calls, (int, float)):
+            g.add_metric([], calls)
+        else:
+            for k, v in calls.items():
+                g.add_metric(k, v)
+
+        yield g
 
     def __attrs_post_init__(self) -> None:
+        self._register()
+
+    def _register(self) -> None:
+        if self.name in all_gauges.keys():
+            logger.warning("%s already registered, reregistering", self.name)
+            REGISTRY.unregister(all_gauges.pop(self.name))
+
         REGISTRY.register(self)
+        all_gauges[self.name] = self
 
 
 # `MetricsEntry` only makes sense when it is a `Protocol`,
@@ -254,7 +250,7 @@ def __init__(
         # Protects access to _registrations
         self._lock = threading.Lock()
 
-        REGISTRY.register(self)
+        self._register_with_collector()
 
     def register(
         self,
@@ -345,6 +341,14 @@ def collect(self) -> Iterable[Metric]:
                 gauge.add_metric(labels=key, value=getattr(metrics, name))
             yield gauge
 
+    def _register_with_collector(self) -> None:
+        if self.name in all_gauges.keys():
+            logger.warning("%s already registered, reregistering", self.name)
+            REGISTRY.unregister(all_gauges.pop(self.name))
+
+        REGISTRY.register(self)
+        all_gauges[self.name] = self
+
 
 class GaugeHistogramMetricFamilyWithLabels(GaugeHistogramMetricFamily):
     """

synapse/metrics/__init__.py

@@ -86,24 +86,6 @@
     labelnames=["stream", SERVER_NAME_LABEL],
 )
 
-
-notifier_listeners_gauge = LaterGauge(
-    name="synapse_notifier_listeners",
-    desc="",
-    labelnames=[SERVER_NAME_LABEL],
-)
-
-notifier_rooms_gauge = LaterGauge(
-    name="synapse_notifier_rooms",
-    desc="",
-    labelnames=[SERVER_NAME_LABEL],
-)
-notifier_users_gauge = LaterGauge(
-    name="synapse_notifier_users",
-    desc="",
-    labelnames=[SERVER_NAME_LABEL],
-)
-
 T = TypeVar("T")
 
 
@@ -299,16 +281,28 @@ def count_listeners() -> Mapping[Tuple[str, ...], int]:
                 )
             }
 
-        notifier_listeners_gauge.register_hook(count_listeners)
-        notifier_rooms_gauge.register_hook(
-            lambda: {
+        LaterGauge(
+            name="synapse_notifier_listeners",
+            desc="",
+            labelnames=[SERVER_NAME_LABEL],
+            caller=count_listeners,
+        )
+
+        LaterGauge(
+            name="synapse_notifier_rooms",
+            desc="",
+            labelnames=[SERVER_NAME_LABEL],
+            caller=lambda: {
                 (self.server_name,): count(
                     bool, list(self.room_to_user_streams.values())
                 )
-            }
+            },
         )
-        notifier_users_gauge.register_hook(
-            lambda: {(self.server_name,): len(self.user_to_user_stream)}
+        LaterGauge(
+            name="synapse_notifier_users",
+            desc="",
+            labelnames=[SERVER_NAME_LABEL],
+            caller=lambda: {(self.server_name,): len(self.user_to_user_stream)},
         )
 
     def add_replication_callback(self, cb: Callable[[], None]) -> None: