Add health check endpoint (#8048)

synapse/rest/health.py

@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 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.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from twisted.web.resource import Resource
+
+
+class HealthResource(Resource):
+    """A resource that does nothing except return a 200 with a body of `OK`,
+    which can be used as a health check.
+
+    Note: `SynapseRequest._should_log_request` ensures that requests to
+    `/health` do not get logged at INFO.
+    """
+
+    isLeaf = 1
+
+    def render_GET(self, request):
+        request.setHeader(b"Content-Type", b"text/plain")
+        return b"OK"