Redis: prevent offline queuing and retries for commands (#18561)

* Add an error handler to ensure the Redis server connection is forcibly closed
* Disable the Redis offline queue and retries

Author: JamesMGreene

lib/redis/create-client.js

@@ -42,10 +42,30 @@ module.exports = function createClient (options = {}) {
       }
     },
 
+    // Any running command that is unfulfilled when a connection is lost should
+    // NOT be retried after the connection has been reestablished.
+    retry_unfulfilled_commands: false,
+
+    // If we failed to send a new command during a disconnection, do NOT
+    // enqueue it to send later after the connection has been [re-]established.
+    // This is also critical to preventing a backend pile-up!
+    enable_offline_queue: false,
+
     // Expand whatever other options and overrides were provided
     ...options
   })
 
+  // Handle connection errors to prevent killing the Node.js process
+  client.on('error', (connectError) => {
+    try {
+      // Forcibly close the connection to the Redis server.
+      // Allow all still running commands to silently fail immediately.
+      client.end(false)
+    } catch (disconnectError) {
+      // Swallow any failure
+    }
+  })
+
   // If a `name` was provided, use it in the prefix for logging event messages
   const logPrefix = '[redis' + (name ? ` (${name})` : '') + ']'