Run Prometheus on a different port, optionally. (#3274)

16 files changed, 192 insertions, 26 deletions

diff --git a/docs/metrics-howto.rst b/docs/metrics-howto.rst
index 8acc479bc3..25e06bca58 100644
--- a/docs/metrics-howto.rst
+++ b/docs/metrics-howto.rst
@@ -1,25 +1,47 @@
 How to monitor Synapse metrics using Prometheus
 ===============================================
 
-1. Install prometheus:
+1. Install Prometheus:
 
    Follow instructions at http://prometheus.io/docs/introduction/install/
 
-2. Enable synapse metrics:
+2. Enable Synapse metrics:
 
-   Simply setting a (local) port number will enable it. Pick a port.
-   prometheus itself defaults to 9090, so starting just above that for
-   locally monitored services seems reasonable. E.g. 9092:
+   There are two methods of enabling metrics in Synapse.
 
-   Add to homeserver.yaml::
+   The first serves the metrics as a part of the usual web server and can be
+   enabled by adding the "metrics" resource to the existing listener as such::
 
-     metrics_port: 9092
+     resources:
+       - names:
+         - client
+         - metrics
 
-   Also ensure that ``enable_metrics`` is set to ``True``.
+   This provides a simple way of adding metrics to your Synapse installation,
+   and serves under ``/_synapse/metrics``. If you do not wish your metrics be
+   publicly exposed, you will need to either filter it out at your load
+   balancer, or use the second method.
 
-   Restart synapse.
+   The second method runs the metrics server on a different port, in a
+   different thread to Synapse. This can make it more resilient to heavy load
+   meaning metrics cannot be retrieved, and can be exposed to just internal
+   networks easier. The served metrics are available over HTTP only, and will
+   be available at ``/``.
 
-3. Add a prometheus target for synapse.
+   Add a new listener to homeserver.yaml::
+
+     listeners:
+       - type: metrics
+         port: 9000
+         bind_addresses:
+           - '0.0.0.0'
+
+   For both options, you will need to ensure that ``enable_metrics`` is set to
+   ``True``.
+
+   Restart Synapse.
+
+3. Add a Prometheus target for Synapse.
 
    It needs to set the ``metrics_path`` to a non-default value (under ``scrape_configs``)::
 
@@ -31,7 +53,40 @@ How to monitor Synapse metrics using Prometheus
    If your prometheus is older than 1.5.2, you will need to replace
    ``static_configs`` in the above with ``target_groups``.
 
-   Restart prometheus.
+   Restart Prometheus.
+
+
+Removal of deprecated metrics & time based counters becoming histograms in 0.31.0
+---------------------------------------------------------------------------------
+
+The duplicated metrics deprecated in Synapse 0.27.0 have been removed.
+
+All time duration-based metrics have been changed to be seconds. This affects:
+
+================================
+msec -> sec metrics
+================================
+python_gc_time
+python_twisted_reactor_tick_time
+synapse_storage_query_time
+synapse_storage_schedule_time
+synapse_storage_transaction_time
+================================
+
+Several metrics have been changed to be histograms, which sort entries into
+buckets and allow better analysis. The following metrics are now histograms:
+
+=========================================
+Altered metrics
+=========================================
+python_gc_time
+python_twisted_reactor_pending_calls
+python_twisted_reactor_tick_time
+synapse_http_server_response_time_seconds
+synapse_storage_query_time
+synapse_storage_schedule_time
+synapse_storage_transaction_time
+=========================================
 
 
 Block and response metrics renamed for 0.27.0
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index e4318cdfc3..a6925ab139 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -124,6 +124,19 @@ def quit_with_error(error_string):
     sys.exit(1)
 
 
+def listen_metrics(bind_addresses, port):
+    """
+    Start Prometheus metrics server.
+    """
+    from synapse.metrics import RegistryProxy
+    from prometheus_client import start_http_server
+
+    for host in bind_addresses:
+        reactor.callInThread(start_http_server, int(port),
+                             addr=host, registry=RegistryProxy)
+        logger.info("Metrics now reporting on %s:%d", host, port)
+
+
 def listen_tcp(bind_addresses, port, factory, backlog=50):
     """
     Create a TCP socket for a port and several addresses
diff --git a/synapse/app/appservice.py b/synapse/app/appservice.py
index b1efacc9f8..dd114dee07 100644
--- a/synapse/app/appservice.py
+++ b/synapse/app/appservice.py
@@ -94,6 +94,13 @@ class AppserviceServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/client_reader.py b/synapse/app/client_reader.py
index 38b98382c6..85dada7f9f 100644
--- a/synapse/app/client_reader.py
+++ b/synapse/app/client_reader.py
@@ -25,6 +25,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -77,7 +78,7 @@ class ClientReaderServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     PublicRoomListRestServlet(self).register(resource)
@@ -118,7 +119,13 @@ class ClientReaderServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
-
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/event_creator.py b/synapse/app/event_creator.py
index bd7f3d5679..5ca77c0f1a 100644
--- a/synapse/app/event_creator.py
+++ b/synapse/app/event_creator.py
@@ -25,6 +25,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
@@ -90,7 +91,7 @@ class EventCreatorServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     RoomSendEventRestServlet(self).register(resource)
@@ -134,6 +135,13 @@ class EventCreatorServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/federation_reader.py b/synapse/app/federation_reader.py
index 6e10b27b9e..2a1995d0cd 100644
--- a/synapse/app/federation_reader.py
+++ b/synapse/app/federation_reader.py
@@ -26,6 +26,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.federation.transport.server import TransportLayerServer
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.directory import DirectoryStore
@@ -71,7 +72,7 @@ class FederationReaderServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "federation":
                     resources.update({
                         FEDERATION_PREFIX: TransportLayerServer(self),
@@ -107,6 +108,13 @@ class FederationReaderServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/federation_sender.py b/synapse/app/federation_sender.py
index 6f24e32d6d..81ad574043 100644
--- a/synapse/app/federation_sender.py
+++ b/synapse/app/federation_sender.py
@@ -25,6 +25,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.federation import send_queue
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
 from synapse.replication.slave.storage.devices import SlavedDeviceStore
@@ -89,7 +90,7 @@ class FederationSenderServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
 
         root_resource = create_resource_tree(resources, NoResource())
 
@@ -121,6 +122,13 @@ class FederationSenderServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/frontend_proxy.py b/synapse/app/frontend_proxy.py
index 0f700ee786..5a164a7a95 100644
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@@ -29,6 +29,7 @@ from synapse.http.servlet import (
     RestServlet, parse_json_object_from_request,
 )
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -131,7 +132,7 @@ class FrontendProxyServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     KeyUploadServlet(self).register(resource)
@@ -172,6 +173,13 @@ class FrontendProxyServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 449bfacdb9..51fc3645d5 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -35,7 +35,7 @@ from synapse.http.additional_resource import AdditionalResource
 from synapse.http.server import RootRedirect
 from synapse.http.site import SynapseSite
 from synapse.metrics import RegistryProxy
-from synapse.metrics.resource import METRICS_PREFIX
+from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.python_dependencies import CONDITIONAL_REQUIREMENTS, \
     check_requirements
 from synapse.replication.http import ReplicationRestResource, REPLICATION_PREFIX
@@ -61,8 +61,6 @@ from twisted.web.resource import EncodingResourceWrapper, NoResource
 from twisted.web.server import GzipEncoderFactory
 from twisted.web.static import File
 
-from prometheus_client.twisted import MetricsResource
-
 logger = logging.getLogger("synapse.app.homeserver")
 
 
@@ -232,7 +230,7 @@ class SynapseHomeServer(HomeServer):
             resources[WEB_CLIENT_PREFIX] = build_resource_for_web_client(self)
 
         if name == "metrics" and self.get_config().enable_metrics:
-            resources[METRICS_PREFIX] = MetricsResource(RegistryProxy())
+            resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
 
         if name == "replication":
             resources[REPLICATION_PREFIX] = ReplicationRestResource(self)
@@ -265,6 +263,13 @@ class SynapseHomeServer(HomeServer):
                     reactor.addSystemEventTrigger(
                         "before", "shutdown", server_listener.stopListening,
                     )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/media_repository.py b/synapse/app/media_repository.py
index 9c93195f0a..006bba80a8 100644
--- a/synapse/app/media_repository.py
+++ b/synapse/app/media_repository.py
@@ -27,6 +27,7 @@ from synapse.config.homeserver import HomeServerConfig
 from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -73,7 +74,7 @@ class MediaRepositoryServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "media":
                     media_repo = self.get_media_repository_resource()
                     resources.update({
@@ -114,6 +115,13 @@ class MediaRepositoryServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/pusher.py b/synapse/app/pusher.py
index 3912eae48c..64df47f9cc 100644
--- a/synapse/app/pusher.py
+++ b/synapse/app/pusher.py
@@ -23,6 +23,7 @@ from synapse.config._base import ConfigError
 from synapse.config.homeserver import HomeServerConfig
 from synapse.config.logger import setup_logging
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
 from synapse.replication.slave.storage.events import SlavedEventStore
@@ -92,7 +93,7 @@ class PusherServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
 
         root_resource = create_resource_tree(resources, NoResource())
 
@@ -124,6 +125,13 @@ class PusherServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index c6294a7a0c..6808d6d3e0 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -26,6 +26,7 @@ from synapse.config.logger import setup_logging
 from synapse.handlers.presence import PresenceHandler, get_interested_parties
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
@@ -257,7 +258,7 @@ class SynchrotronServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     sync.register_servlets(self, resource)
@@ -301,6 +302,13 @@ class SynchrotronServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/user_dir.py b/synapse/app/user_dir.py
index 53eb3474da..ada1c13cec 100644
--- a/synapse/app/user_dir.py
+++ b/synapse/app/user_dir.py
@@ -26,6 +26,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -105,7 +106,7 @@ class UserDirectoryServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     user_directory.register_servlets(self, resource)
@@ -146,6 +147,13 @@ class UserDirectoryServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 8f0b6d1f28..968ecd9ea0 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -14,8 +14,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from ._base import Config, ConfigError
 
+logger = logging.Logger(__name__)
+
 
 class ServerConfig(Config):
 
@@ -138,6 +142,12 @@ class ServerConfig(Config):
 
         metrics_port = config.get("metrics_port")
         if metrics_port:
+            logger.warn(
+                ("The metrics_port configuration option is deprecated in Synapse 0.31 "
+                 "in favour of a listener. Please see "
+                 "http://github.com/matrix-org/synapse/blob/master/docs/metrics-howto.rst"
+                 " on how to configure the new listener."))
+
             self.listeners.append({
                 "port": metrics_port,
                 "bind_addresses": [config.get("metrics_bind_host", "127.0.0.1")],
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index bfdbbc9a23..56c0032f91 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -39,7 +39,8 @@ HAVE_PROC_SELF_STAT = os.path.exists("/proc/self/stat")
 
 class RegistryProxy(object):
 
-    def collect(self):
+    @staticmethod
+    def collect():
         for metric in REGISTRY.collect():
             if not metric.name.startswith("__"):
                 yield metric
diff --git a/synapse/metrics/resource.py b/synapse/metrics/resource.py
index 7996e6ab66..9789359077 100644
--- a/synapse/metrics/resource.py
+++ b/synapse/metrics/resource.py
@@ -13,4 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from prometheus_client.twisted import MetricsResource
+
 METRICS_PREFIX = "/_synapse/metrics"
+
+__all__ = ["MetricsResource", "METRICS_PREFIX"]