Fixup comments and add warning

changelog.d/4632.feature

@@ -1 +1 @@
-Add basic optional sentry.io integration
+Add basic optional sentry integration

synapse/app/_base.py

@@ -269,7 +269,7 @@ def start(hs, listeners=None):
         hs.start_listening(listeners)
         hs.get_datastore().start_profiling()
 
-        setup_sentry_io(hs)
+        setup_sentry(hs)
     except Exception:
         traceback.print_exc(file=sys.stderr)
         reactor = hs.get_reactor()
@@ -278,8 +278,8 @@ def start(hs, listeners=None):
         sys.exit(1)
 
 
-def setup_sentry_io(hs):
-    """Enable sentry.io integration, if enabled in configuration
+def setup_sentry(hs):
+    """Enable sentry integration, if enabled in configuration
 
     Args:
         hs (synapse.server.HomeServer)

synapse/config/metrics.py

@@ -16,7 +16,7 @@
 from ._base import Config, ConfigError
 
 MISSING_SENTRY = (
-    """Missing sentry_sdk library. This is required for enable sentry.io
+    """Missing sentry_sdk library. This is required for enable sentry
     integration.
 
     Install by running:
@@ -48,7 +48,12 @@ class MetricsConfig(Config):
         # Enable collection and rendering of performance metrics
         enable_metrics: False
 
-        # Enable sentry.io integration
+        # Enable sentry integration
+        # NOTE: While attempts are made to ensure that the logs don't contain
+        # any sensitive information, this cannot be guaranteed. By enabling
+        # this option the sentry server may therefore receive sensitive
+        # information, and it in turn may then diseminate sensitive information
+        # through insecure notification channels if so configured.
         #sentry:
         #    dsn: "..."
         """