Servers-known-about statistic

changelog.d/5981.feature

@@ -0,0 +1 @@
+Setting metrics_flags.known_servers to True in the configuration will publish the synapse_federation_known_servers metric over Prometheus. This represents the total number of servers your server knows about (i.e. is in rooms with), including itself.

docs/sample_config.yaml

@@ -926,6 +926,16 @@ uploads_path: "DATADIR/uploads"
 #sentry:
 # dsn: "..."
 
+# Flags to enable Prometheus metrics which are not suitable to be
+# enabled by default, either for performance reasons or limited use.
+#
+metrics_flags:
+ # Publish synapse_federation_known_servers, a g auge of the number of
+ # servers this homeserver knows about, including itself. May cause
+ # performance problems on large homeservers.
+ #
+ #known_servers: true
+
 # Whether or not to report anonymized homeserver usage statistics.
 # report_stats: true|false
 

synapse/config/metrics.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
+# Copyright 2019 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,20 +14,40 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import attr
+
 from ._base import Config, ConfigError
 
 MISSING_SENTRY = """Missing sentry-sdk library. This is required to enable sentry
  integration.
  """
 
 
+@attr.s
+class MetricsFlags(object):
+ known_servers = attr.ib(default=False, validator=attr.validators.instance_of(bool))
+
+ @classmethod
+ def all_off(cls):
+ """
+ Instantiate the flags with all options set to off.
+ """
+ return cls(**{x.name: False for x in attr.fields(cls)})
+
+
 class MetricsConfig(Config):
  def read_config(self, config, **kwargs):
  self.enable_metrics = config.get("enable_metrics", False)
  self.report_stats = config.get("report_stats", None)
  self.metrics_port = config.get("metrics_port")
  self.metrics_bind_host = config.get("metrics_bind_host", "127.0.0.1")
 
+ if self.enable_metrics:
+ _metrics_config = config.get("metrics_flags") or {}
+ self.metrics_flags = MetricsFlags(**_metrics_config)
+ else:
+ self.metrics_flags = MetricsFlags.all_off()
+
  self.sentry_enabled = "sentry" in config
  if self.sentry_enabled:
  try:
@@ -58,6 +79,16 @@ def generate_config_section(self, report_stats=None, **kwargs):
  #sentry:
  # dsn: "..."
 
+ # Flags to enable Prometheus metrics which are not suitable to be
+ # enabled by default, either for performance reasons or limited use.
+ #
+ metrics_flags:
+ # Publish synapse_federation_known_servers, a g auge of the number of
+ # servers this homeserver knows about, including itself. May cause
+ # performance problems on large homeservers.
+ #
+ #known_servers: true
+
  # Whether or not to report anonymized homeserver usage statistics.
  """
 

synapse/storage/roommember.py

@@ -24,8 +24,10 @@
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
+from synapse.metrics import LaterGauge
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import LoggingTransaction
+from synapse.storage.engines import Sqlite3Engine
 from synapse.storage.events_worker import EventsWorkerStore
 from synapse.types import get_domain_from_id
 from synapse.util.async_helpers import Linearizer
@@ -74,6 +76,63 @@ def __init__(self, db_conn, hs):
  self._check_safe_current_state_events_membership_updated_txn(txn)
  txn.close()
 
+ if self.hs.config.metrics_flags.known_servers:
+ self._known_servers_count = 1
+ self.hs.get_clock().looping_call(
+ run_as_background_process,
+ 60 * 1000,
+ "_count_known_servers",
+ self._count_known_servers,
+ )
+ self.hs.get_clock().call_later(
+ 1000,
+ run_as_background_process,
+ "_count_known_servers",
+ self._count_known_servers,
+ )
+ LaterGauge(
+ "synapse_federation_known_servers",
+ "",
+ [],
+ lambda: self._known_servers_count,
+ )
+
+ @defer.inlineCallbacks
+ def _count_known_servers(self):
+ """
+ Count the servers that this server knows about.
+
+ The statistic is stored on the class for the
+ `synapse_federation_known_servers` LaterGauge to collect.
+ """
+
+ def _transact(txn):
+ if isinstance(self.database_engine, Sqlite3Engine):
+ query = """
+ SELECT COUNT(DISTINCT substr(out.user_id, pos+1))
+ FROM (
+ SELECT rm.user_id as user_id, instr(rm.user_id, ':')
+ AS pos FROM room_memberships as rm
+ INNER JOIN current_state_events as c ON rm.event_id = c.event_id
+ WHERE c.type = 'm.room.member'
+ ) as out
+ """
+ else:
+ query = """
+ SELECT COUNT(DISTINCT split_part(state_key, ':', 2))
+ FROM current_state_events
+ WHERE type = 'm.room.member' AND membership = 'join';
+ """
+ txn.execute(query)
+ return list(txn)[0][0]
+
+ count = yield self.runInteraction("get_known_servers", _transact)
+
+ # We always know about ourselves, even if we have nothing in
+ # room_memberships (for example, the server is new).
+ self._known_servers_count = max([count, 1])
+ return self._known_servers_count
+
  def _check_safe_current_state_events_membership_updated_txn(self, txn):
  """Checks if it is safe to assume the new current_state_events
  membership column is up to date

tests/config/test_generate.py

@@ -17,6 +17,8 @@
 import re
 import shutil
 import tempfile
+from contextlib import redirect_stdout
+from io import StringIO
 
 from synapse.config.homeserver import HomeServerConfig
 
@@ -32,17 +34,18 @@ def tearDown(self):
  shutil.rmtree(self.dir)
 
  def test_generate_config_generates_files(self):
- HomeServerConfig.load_or_generate_config(
- "",
- [
- "--generate-config",
- "-c",
- self.file,
- "--report-stats=yes",
- "-H",
- "lemurs.win",
- ],
- )
+ with redirect_stdout(StringIO()):
+ HomeServerConfig.load_or_generate_config(
+ "",
+ [
+ "--generate-config",
+ "-c",
+ self.file,
+ "--report-stats=yes",
+ "-H",
+ "lemurs.win",
+ ],
+ )
 
  self.assertSetEqual(
  set(["homeserver.yaml", "lemurs.win.log.config", "lemurs.win.signing.key"]),

tests/config/test_load.py

@@ -15,6 +15,8 @@
 import os.path
 import shutil
 import tempfile
+from contextlib import redirect_stdout
+from io import StringIO
 
 import yaml
 
@@ -26,7 +28,6 @@
 class ConfigLoadingTestCase(unittest.TestCase):
  def setUp(self):
  self.dir = tempfile.mkdtemp()
- print(self.dir)
  self.file = os.path.join(self.dir, "homeserver.yaml")
 
  def tearDown(self):
@@ -94,18 +95,27 @@ def test_disable_registration(self):
  )
  self.assertTrue(config.enable_registration)
 
+ def test_stats_enabled(self):
+ self.generate_config_and_remove_lines_containing("enable_metrics")
+ self.add_lines_to_config(["enable_metrics: true"])
+
+ # The default Metrics Flags are off by default.
+ config = HomeServerConfig.load_config("", ["-c", self.file])
+ self.assertFalse(config.metrics_flags.known_servers)
+
  def generate_config(self):
- HomeServerConfig.load_or_generate_config(
- "",
- [
- "--generate-config",
- "-c",
- self.file,
- "--report-stats=yes",
- "-H",
- "lemurs.win",
- ],
- )
+ with redirect_stdout(StringIO()):
+ HomeServerConfig.load_or_generate_config(
+ "",
+ [
+ "--generate-config",
+ "-c",
+ self.file,
+ "--report-stats=yes",
+ "-H",
+ "lemurs.win",
+ ],
+ )
 
  def generate_config_and_remove_lines_containing(self, needle):
  self.generate_config()