feat: add redis liveness probe

documentation/api/change_log.rst

@@ -9,6 +9,7 @@ v3.0-10 | 2023-06-12
 """"""""""""""""""""
 
 - Introduced the ``storage-efficiency`` field to the ``flex-model``field for `/sensors/<id>/schedules/trigger` (POST).
+- Introduced the ``database_redis`` optional field to the response of the endpoint `/health/ready` (GET).
 
 v3.0-9 | 2023-04-26
 """""""""""""""""""

documentation/changelog.rst

@@ -23,8 +23,11 @@ Infrastructure / Support
 ----------------------
 
 * Add support for profiling Flask API calls using ``pyinstrument`` (if installed). Can be enabled by setting the environment variable ``FLEXMEASURES_PROFILE_REQUESTS`` to ``True`` [see `PR #722 <https://www.github.com/FlexMeasures/flexmeasures/pull/722>`_]
+* The endpoint `[POST] /health/ready <api/v3_0.html#get--api-v3_0-health-ready>`_ returns the status of the Redis connection, if configured [see `PR #699 <https://www.github.com/FlexMeasures/flexmeasures/pull/699>`_]
 
 
+/api/v3_0/health/ready
+
 v0.14.1 | June 26, 2023
 ============================
 

flexmeasures/api/v3_0/health.py

@@ -2,6 +2,8 @@
 from flask_classful import FlaskView, route
 from flask_json import as_json
 
+
+from redis.exceptions import ConnectionError
 from flexmeasures.data import db
 
 
@@ -14,6 +16,18 @@ def _check_sql_database():
         return False
 
 
+def _check_redis() -> bool:
+    """Check status of the redis instance
+
+    :return: True if the redis instance is active, False otherwise
+    """
+    try:
+        current_app.redis_connection.ping()
+        return True
+    except ConnectionError:
+        return False
+
+
 class HealthAPI(FlaskView):
 
     route_base = "/health"
@@ -32,11 +46,19 @@ def is_ready(self):
         .. sourcecode:: json
 
             {
-                'database_sql': True
+                'database_sql': True,
+                'database_redis': False
             }
 
         """
-        status = {"database_sql": _check_sql_database()}  # TODO: check redis
+
+        status = {
+            "database_sql": _check_sql_database(),
+        }
+
+        if current_app.config.get("FLEXMEASURES_REDIS_PASSWORD") is not None:
+            status["database_redis"] = _check_redis()
+
         if all(status.values()):
             return status, 200
         else: