OpenConceptLab/ocl_issues#927 Redis clustering, fixing redis healthcheck

core/common/healthcheck/healthcheck.py

@@ -1,8 +1,11 @@
 from celery.app import default_app as celery_app
 from django.conf import settings
-from health_check.backends import BaseHealthCheckBackend
+from django_redis import get_redis_connection
+from health_check.backends import BaseHealthCheckBackend, logger
+from health_check.contrib.redis.backends import RedisHealthCheck
 from health_check.exceptions import ServiceReturnedUnexpectedResult, ServiceUnavailable
 from pydash import get
+from redis import exceptions
 
 from core.common.utils import flower_get, es_get
 
@@ -18,6 +21,29 @@ def check_status(self):
         raise NotImplementedError
 
 
+class RedisHealthCheck(BaseHealthCheck):
+
+    def check_status(self):
+        """Check Redis service by pinging the redis instance with a redis connection."""
+        try:
+            # conn is used as a context to release opened resources later
+            with get_redis_connection('default') as conn:
+                conn.ping()  # exceptions may be raised upon ping
+        except ConnectionRefusedError as e:
+            self.add_error(ServiceUnavailable("Unable to connect to Redis: Connection was refused."), e)
+        except exceptions.TimeoutError as e:
+            self.add_error(ServiceUnavailable("Unable to connect to Redis: Timeout."), e)
+        except exceptions.ConnectionError as e:
+            self.add_error(ServiceUnavailable("Unable to connect to Redis: Connection Error"), e)
+        except BaseException as e:
+            self.add_error(ServiceUnavailable("Unknown error"), e)
+        else:
+            logger.debug("Connection established. Redis is healthy.")
+
+    def identifier(self):
+        return "Redis"
+
+
 class FlowerHealthCheck(BaseHealthCheck):
     critical_service = False
 

core/common/healthcheck/views.py

@@ -1,11 +1,10 @@
-from health_check.contrib.redis.backends import RedisHealthCheck
 from health_check.db.backends import DatabaseBackend
 from health_check.views import MainView
 
 from core.common.healthcheck.healthcheck import FlowerHealthCheck, CeleryDefaultQueueHealthCheck, \
     CeleryBulkImport0QueueHealthCheck, CeleryBulkImportRootQueueHealthCheck, CeleryBulkImport3QueueHealthCheck, \
     CeleryBulkImport2QueueHealthCheck, CeleryBulkImport1QueueHealthCheck, CeleryConcurrentThreadsHealthCheck, \
-    ESHealthCheck, CeleryIndexingQueueHealthCheck
+    ESHealthCheck, CeleryIndexingQueueHealthCheck, RedisHealthCheck
 
 
 class BaseHealthcheckView(MainView):

core/settings.py

@@ -83,7 +83,6 @@
     'health_check',  # required
     'health_check.db',  # stock Django health checkers
     # 'health_check.contrib.celery_ping',  # requires celery
-    'health_check.contrib.redis',  # requires Redis broker
     'core.common.apps.CommonConfig',
     'core.users',
     'core.orgs',