fix(svc): properly use Redis sentinel (#3319)

Author: Panaetius

renku/ui/cli/service.py

@@ -176,7 +176,7 @@ def read_logs(log_file, follow=True, output_all=False):
 @click.pass_context
 def service(ctx, env):
     """Manage service components."""
-    import redis  # noqa: F401
+    import redis
     import rq  # noqa: F401
     from dotenv import load_dotenv
 
@@ -196,10 +196,9 @@ def service(ctx, env):
 
         ctx.exit(1)
 
-    except redis.exceptions.ConnectionError:
+    except redis.exceptions.ConnectionError as e:
         # NOTE: Cannot connect to the service dependencies, ie. Redis.
-
-        click.echo(ERROR + "Cannot connect to Redis")
+        click.echo(ERROR + f"Cannot connect to Redis: {e}")
 
         ctx.exit(1)
 

renku/ui/service/cache/base.py

@@ -18,28 +18,43 @@
 """Renku service cache management."""
 import json
 import os
+from typing import Any, Dict
 
 import redis
 from redis import RedisError
 from walrus import Database
 
-from renku.ui.service.cache.config import REDIS_DATABASE, REDIS_HOST, REDIS_NAMESPACE, REDIS_PASSWORD, REDIS_PORT
+from renku.ui.service.cache.config import (
+    REDIS_DATABASE,
+    REDIS_HOST,
+    REDIS_IS_SENTINEL,
+    REDIS_MASTER_SET,
+    REDIS_NAMESPACE,
+    REDIS_PASSWORD,
+    REDIS_PORT,
+)
+
+_config: Dict[str, Any] = {
+    "db": REDIS_DATABASE,
+    "password": REDIS_PASSWORD,
+    "retry_on_timeout": True,
+    "health_check_interval": int(os.getenv("CACHE_HEALTH_CHECK_INTERVAL", 60)),
+}
+
+if REDIS_IS_SENTINEL:
+    _sentinel = redis.Sentinel([(REDIS_HOST, REDIS_PORT)], sentinel_kwargs={"password": REDIS_PASSWORD})
+    _cache = _sentinel.master_for(REDIS_MASTER_SET, **_config)
+    _model_db = Database(connection_pool=_cache.connection_pool, **_config)
+else:
+    _cache = redis.Redis(host=REDIS_HOST, port=REDIS_PORT, **_config)  # type: ignore
+    _model_db = Database(host=REDIS_HOST, port=REDIS_PORT, **_config)
 
 
 class BaseCache:
     """Cache management."""
 
-    config_ = {
-        "host": REDIS_HOST,
-        "port": REDIS_PORT,
-        "db": REDIS_DATABASE,
-        "password": REDIS_PASSWORD,
-        "retry_on_timeout": True,
-        "health_check_interval": int(os.getenv("CACHE_HEALTH_CHECK_INTERVAL", 60)),
-    }
-
-    cache = redis.Redis(**config_)  # type: ignore
-    model_db = Database(**config_)
+    cache: redis.Redis = _cache
+    model_db: Database = _model_db
     namespace = REDIS_NAMESPACE
 
     def set_record(self, name, key, value):

renku/ui/service/cache/config.py

@@ -27,11 +27,3 @@
 
 REDIS_IS_SENTINEL = os.environ.get("REDIS_IS_SENTINEL", "") == "true"
 REDIS_MASTER_SET = os.environ.get("REDIS_MASTER_SET", "mymaster")
-if REDIS_IS_SENTINEL:
-    from redis.sentinel import Sentinel
-
-    sentinel = Sentinel(
-        [(REDIS_HOST, REDIS_PORT)],
-        sentinel_kwargs={"password": REDIS_PASSWORD},
-    )
-    REDIS_HOST, REDIS_PORT = sentinel.discover_master(REDIS_MASTER_SET)