Does fetchSockets return all sockets from all nodes?

[nicholaswmin]

We're using @socket.io/redis-adapter because we're running socket.io on 4 dynos/nodes and we want this to work in a horizontally scalable way.

We need to fetch all the sockets in a particular room regardless of the dyno/node they connected to.

The question:

Does const sockets = await io.of('/').in('room1').fetchSockets() fetch all the sockets across all nodes/dynos for a room? Our experiments indicate that this is indeed the case but we'd like to confirm it :)

[darrachequesne]

@nicholaswmin yes it does! You can also use the local flag if you need it:

// all sockets across all nodes
const allSockets = await io.in("room1").fetchSockets();

// all sockets on the node
const sockets = await io.local.in("room1").fetchSockets();

Reference: https://socket.io/docs/v4/server-api/#serverfetchsockets