Azure Cache for Redis failover reconnect

Question

I'm using Azure Cache for Redis.

When using the node-redis package to connect to Redis in Node.js, there's an issue with automatically reconnecting when Redis doing an upgrade. In .NET, you can use ForceReconnect, but how can this be implemented in Node.js?

Here are the settings:

const redisConfig = {
    url: `redis://${REDIS_HOST}:${REDIS_PORT}`,
    socket: {
        host: REDIS_HOST,
        port: Number(REDIS_PORT),
        reconnectStrategy: (retries) => (retries < 5 ? 100 : 5000),
    },
    password: REDIS_PWD,
    database: Number(REDIS_DB_NUMBER),
    // Azure Redis has a 10-minute timeout for idle connections
    pingInterval: 4 * 60 * 1000,
};

Answer

@Oury Ba-MSFT
The support ticket indicates that during an update at either the Redis or OS level, as well as during a manual reboot (https://zcusa.951200.xyz/en-us/azure/azure-cache-for-redis/cache-failover#explanation-of-a-failover), the Redis server will send a FIN network packet to notify the client. If the client's logic can correctly identify the FIN packet, disconnect, and then re-establish the connection, the client can quickly reconnect.

Here's my solution:

const client = redis.createClient(redisConfig);

// REAL CASE should wrapped in async function
client.connect();

client.on('error', async (err) => {
    switch (err.message) {
        // SOLUTION
        case 'Socket closed unexpectedly':
            console.log('Closing Redis connection...');
            await client.disconnect();
            await utils.sleep(3000);
            console.log('Trying reconnecting Redis...');
            await client.connect();
            break;
        default:
            break;
    }
});

I am unable to verify it now, and will have to wait until the next update to confirm if it's effective.

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Azure Cache for Redis failover reconnect

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