harden connections to redis (#2677)

* set broker_connection_retry_on_startup to silence deprecation warning (we're OK with retrying on startup)

* env var for CELERY_BROKER_POOL_LIMIT

* add redis retry on timeout and health check interval

* set socket_keepalive = True

* remove shadow declaration of REDIS_HEALTH_CHECK_INTERVAL, add socket_keepalive_options where possible

* fix mypy complaint

* pass through vars in docker compose

* remove extra '='

* wrap in a try

backend/danswer/background/celery/celeryconfig.py

@@ -1,7 +1,9 @@
 # docs: https://docs.celeryq.dev/en/stable/userguide/configuration.html
+from danswer.configs.app_configs import CELERY_BROKER_POOL_LIMIT
 from danswer.configs.app_configs import CELERY_RESULT_EXPIRES
 from danswer.configs.app_configs import REDIS_DB_NUMBER_CELERY
 from danswer.configs.app_configs import REDIS_DB_NUMBER_CELERY_RESULT_BACKEND
+from danswer.configs.app_configs import REDIS_HEALTH_CHECK_INTERVAL
 from danswer.configs.app_configs import REDIS_HOST
 from danswer.configs.app_configs import REDIS_PASSWORD
 from danswer.configs.app_configs import REDIS_PORT
@@ -9,6 +11,7 @@ from danswer.configs.app_configs import REDIS_SSL
 from danswer.configs.app_configs import REDIS_SSL_CA_CERTS
 from danswer.configs.app_configs import REDIS_SSL_CERT_REQS
 from danswer.configs.constants import DanswerCeleryPriority
+from danswer.configs.constants import REDIS_SOCKET_KEEPALIVE_OPTIONS
 
 CELERY_SEPARATOR = ":"
 
@@ -36,12 +39,30 @@ result_backend = f"{REDIS_SCHEME}://{CELERY_PASSWORD_PART}{REDIS_HOST}:{REDIS_PO
 # can stall other tasks.
 worker_prefetch_multiplier = 4
 
+broker_connection_retry_on_startup = True
+broker_pool_limit = CELERY_BROKER_POOL_LIMIT
+
+# redis broker settings
+# https://docs.celeryq.dev/projects/kombu/en/stable/reference/kombu.transport.redis.html
 broker_transport_options = {
     "priority_steps": list(range(len(DanswerCeleryPriority))),
     "sep": CELERY_SEPARATOR,
     "queue_order_strategy": "priority",
+    "retry_on_timeout": True,
+    "health_check_interval": REDIS_HEALTH_CHECK_INTERVAL,
+    "socket_keepalive": True,
+    "socket_keepalive_options": REDIS_SOCKET_KEEPALIVE_OPTIONS,
 }
 
+# redis backend settings
+# https://docs.celeryq.dev/en/stable/userguide/configuration.html#redis-backend-settings
+
+# there doesn't appear to be a way to set socket_keepalive_options on the redis result backend
+redis_socket_keepalive = True
+redis_retry_on_timeout = True
+redis_backend_health_check_interval = REDIS_HEALTH_CHECK_INTERVAL
+
+
 task_default_priority = DanswerCeleryPriority.MEDIUM
 task_acks_late = True
 

backend/danswer/configs/app_configs.py

@@ -164,6 +164,12 @@ REDIS_DB_NUMBER_CELERY_RESULT_BACKEND = int(
 )
 REDIS_DB_NUMBER_CELERY = int(os.environ.get("REDIS_DB_NUMBER_CELERY", 15))  # broker
 
+# will propagate to both our redis client as well as celery's redis client
+REDIS_HEALTH_CHECK_INTERVAL = int(os.environ.get("REDIS_HEALTH_CHECK_INTERVAL", 60))
+
+# our redis client only, not celery's
+REDIS_POOL_MAX_CONNECTIONS = int(os.environ.get("REDIS_POOL_MAX_CONNECTIONS", 128))
+
 # https://docs.celeryq.dev/en/stable/userguide/configuration.html#redis-backend-settings
 # should be one of "required", "optional", or "none"
 REDIS_SSL_CERT_REQS = os.getenv("REDIS_SSL_CERT_REQS", "none")
@@ -171,6 +177,16 @@ REDIS_SSL_CA_CERTS = os.getenv("REDIS_SSL_CA_CERTS", None)
 
 CELERY_RESULT_EXPIRES = int(os.environ.get("CELERY_RESULT_EXPIRES", 86400))  # seconds
 
+# https://docs.celeryq.dev/en/stable/userguide/configuration.html#broker-pool-limit
+# Setting to None may help when there is a proxy in the way closing idle connections
+CELERY_BROKER_POOL_LIMIT_DEFAULT = 10
+try:
+    CELERY_BROKER_POOL_LIMIT = int(
+        os.environ.get("CELERY_BROKER_POOL_LIMIT", CELERY_BROKER_POOL_LIMIT_DEFAULT)
+    )
+except ValueError:
+    CELERY_BROKER_POOL_LIMIT = CELERY_BROKER_POOL_LIMIT_DEFAULT
+
 #####
 # Connector Configs
 #####

backend/danswer/configs/constants.py

@@ -1,3 +1,5 @@
+import platform
+import socket
 from enum import auto
 from enum import Enum
 
@@ -204,3 +206,13 @@ class DanswerCeleryPriority(int, Enum):
     MEDIUM = auto()
     LOW = auto()
     LOWEST = auto()
+
+
+REDIS_SOCKET_KEEPALIVE_OPTIONS = {}
+REDIS_SOCKET_KEEPALIVE_OPTIONS[socket.TCP_KEEPINTVL] = 15
+REDIS_SOCKET_KEEPALIVE_OPTIONS[socket.TCP_KEEPCNT] = 3
+
+if platform.system() == "Darwin":
+    REDIS_SOCKET_KEEPALIVE_OPTIONS[socket.TCP_KEEPALIVE] = 60  # type: ignore
+else:
+    REDIS_SOCKET_KEEPALIVE_OPTIONS[socket.TCP_KEEPIDLE] = 60  # type: ignore

backend/danswer/redis/redis_pool.py

@@ -5,14 +5,15 @@ import redis
 from redis.client import Redis
 
 from danswer.configs.app_configs import REDIS_DB_NUMBER
+from danswer.configs.app_configs import REDIS_HEALTH_CHECK_INTERVAL
 from danswer.configs.app_configs import REDIS_HOST
 from danswer.configs.app_configs import REDIS_PASSWORD
+from danswer.configs.app_configs import REDIS_POOL_MAX_CONNECTIONS
 from danswer.configs.app_configs import REDIS_PORT
 from danswer.configs.app_configs import REDIS_SSL
 from danswer.configs.app_configs import REDIS_SSL_CA_CERTS
 from danswer.configs.app_configs import REDIS_SSL_CERT_REQS
-
+from danswer.configs.constants import REDIS_SOCKET_KEEPALIVE_OPTIONS
-REDIS_POOL_MAX_CONNECTIONS = 128
 
 
 class RedisPool:
@@ -59,6 +60,9 @@ class RedisPool:
                 password=password,
                 max_connections=max_connections,
                 timeout=None,
+                health_check_interval=REDIS_HEALTH_CHECK_INTERVAL,
+                socket_keepalive=True,
+                socket_keepalive_options=REDIS_SOCKET_KEEPALIVE_OPTIONS,
                 connection_class=redis.SSLConnection,
                 ssl_ca_certs=ssl_ca_certs,
                 ssl_cert_reqs=ssl_cert_reqs,
@@ -71,6 +75,9 @@ class RedisPool:
             password=password,
             max_connections=max_connections,
             timeout=None,
+            health_check_interval=REDIS_HEALTH_CHECK_INTERVAL,
+            socket_keepalive=True,
+            socket_keepalive_options=REDIS_SOCKET_KEEPALIVE_OPTIONS,
         )
 
 

deployment/docker_compose/docker-compose.dev.yml

@@ -87,6 +87,7 @@ services:
       - LOG_ENDPOINT_LATENCY=${LOG_ENDPOINT_LATENCY:-}
       - LOG_POSTGRES_LATENCY=${LOG_POSTGRES_LATENCY:-}
       - LOG_POSTGRES_CONN_COUNTS=${LOG_POSTGRES_CONN_COUNTS:-}
+      - CELERY_BROKER_POOL_LIMIT=${CELERY_BROKER_POOL_LIMIT:-}
 
       # Chat Configs
       - HARD_DELETE_CHATS=${HARD_DELETE_CHATS:-}

deployment/docker_compose/docker-compose.gpu-dev.yml

@@ -80,6 +80,7 @@ services:
       # If set to `true` will enable additional logs about Vespa query performance
       # (time spent on finding the right docs + time spent fetching summaries from disk)
       - LOG_VESPA_TIMING_INFORMATION=${LOG_VESPA_TIMING_INFORMATION:-}
+      - CELERY_BROKER_POOL_LIMIT=${CELERY_BROKER_POOL_LIMIT:-}
       
       # Chat Configs
       - HARD_DELETE_CHATS=${HARD_DELETE_CHATS:-}