socket.io-multi-redis
v3.0.2
Published
The Socket.IO Redis adapter, allowing to broadcast events between several Socket.IO servers
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socket.io-multi-redis
The socket.io-multi-redis
package allows broadcasting packets between multiple Socket.IO servers.
socket.io-multi-redis Uses Custom Scaling Solution.
By running socket.io with the socket.io-multi-redis
adapter you can run
multiple socket.io instances in different processes or servers that can
all broadcast and emit events to and from each other with any number of redis server connections.
Table of contents
Supported features
| Feature | socket.io
version | Support |
|---------------------------------|---------------------|------------------------------------------------|
| Socket management | 4.0.0
| :white_check_mark: YES (since version 6.1.0
) |
| Inter-server communication | 4.1.0
| :white_check_mark: YES (since version 7.0.0
) |
| Broadcast with acknowledgements | 4.5.0
| :white_check_mark: YES (since version 7.2.0
) |
| Connection state recovery | 4.6.0
| :x: NO |
Installation
npm install socket.io-multi-redis
Compatibility table
| Redis Adapter version | Socket.IO server version | |-----------------------|--------------------------| | 2.x | 2.x | | 3.x | 4.3.x and above |
Usage
With the redis
package
import { createClient } from "redis";
import { Server } from "socket.io";
import { createAdapter } from "socket.io-multi-redis";
const pubClient1 = createClient({ url: "redis://localhost:6379" });
const subClient1 = pubClient.duplicate();
const pubClient2 = createClient({ url: "redis://localhost:6380" });
const subClient2 = pubClient.duplicate();
const pubClient3 = createClient({ url: "redis://localhost:6381" });
const subClient3 = pubClient.duplicate();
await Promise.all([
pubClient1.connect(),subClient1.connect(),
pubClient2.connect(),subClient2.connect(),
pubClient3.connect(),subClient3.connect()
]);
const io = new Server({
adapter: createAdapter(
[pubClient1, pubClient2, pubClient3],
[subClient1, subClient2, subClient3],
)
});
io.listen(3000);
With the redis
package and a Redis cluster
import { createCluster } from "redis";
import { Server } from "socket.io";
import { createAdapter } from "socket.io-multi-redis";
const pubClient = createCluster({
rootNodes: [
{
url: "redis://localhost:7000",
},
{
url: "redis://localhost:7001",
},
{
url: "redis://localhost:7002",
},
],
});
const subClient = pubClient.duplicate();
await Promise.all([
pubClient.connect(),
subClient.connect()
]);
const io = new Server({
adapter: createAdapter(pubClient, subClient)
});
io.listen(3000);
With the ioredis
package
import { Redis } from "ioredis";
import { Server } from "socket.io";
import { createAdapter } from "socket.io-multi-redis";
const pubClient1 = new Redis();
const subClient1 = pubClient.duplicate();
const pubClient2 = new Redis();
const subClient2 = pubClient.duplicate();
const pubClient3 = new Redis();
const subClient3 = pubClient.duplicate();
const io = new Server({
adapter: createAdapter(
[pubClient1, pubClient2, pubClient3],
[subClient1, subClient2, subClient3],
)
});
io.listen(3000);
With the ioredis
package and a Redis cluster
import { Cluster } from "ioredis";
import { Server } from "socket.io";
import { createAdapter } from "socket.io-multi-redis";
const pubClient = new Cluster([
{
host: "localhost",
port: 7000,
},
{
host: "localhost",
port: 7001,
},
{
host: "localhost",
port: 7002,
},
]);
const subClient = pubClient.duplicate();
const io = new Server({
adapter: createAdapter(pubClient, subClient)
});
io.listen(3000);
With Redis sharded Pub/Sub
Sharded Pub/Sub was introduced in Redis 7.0 in order to help scaling the usage of Pub/Sub in cluster mode.
Reference: https://redis.io/docs/interact/pubsub/#sharded-pubsub
A dedicated adapter can be created with the createShardedAdapter()
method:
import { Server } from "socket.io";
import { createClient } from "redis";
import { createShardedAdapter } from "socket.io-multi-redis";
const pubClient = createClient({ host: "localhost", port: 6379 });
const subClient = pubClient.duplicate();
await Promise.all([
pubClient.connect(),
subClient.connect()
]);
const io = new Server({
adapter: createShardedAdapter(pubClient, subClient)
});
io.listen(3000);
Minimum requirements:
- Redis 7.0
[email protected]
Note: it is not currently possible to use the sharded adapter with the ioredis
package and a Redis cluster (reference).
Options
Default adapter
| Name | Description | Default value |
|------------------------------------|-------------------------------------------------------------------------------|---------------|
| key
| The prefix for the Redis Pub/Sub channels. | socket.io
|
| requestsTimeout
| After this timeout the adapter will stop waiting from responses to request. | 5_000
|
| publishOnSpecificResponseChannel
| Whether to publish a response to the channel specific to the requesting node. | false
|
| parser
| The parser to use for encoding and decoding messages sent to Redis. | -
|
Sharded adapter
| Name | Description | Default value |
|--------------------|-----------------------------------------------------------------------------------------|---------------|
| channelPrefix
| The prefix for the Redis Pub/Sub channels. | socket.io
|
| subscriptionMode
| The subscription mode impacts the number of Redis Pub/Sub channels used by the adapter. | dynamic
|