Socket.IO server
Node.js real-time server with WebSocket and long-polling transports.
- Provider
- default
- Category
- Edge
- Official docs
- https://socket.io/docs/v4/
| property | type | values | required | kind default | this component |
|---|---|---|---|---|---|
| ackIntervalSeconds | integer | — | no | — | inherited |
| adapter | enum | in-memory | redis | mongo | postgres | no | in-memory | inherited |
| autoscaling | boolean | — | no | false | inherited |
| channelAssignment | enum | random | hash | sticky | no | random | inherited |
| drainOnScaleIn | boolean | — | no | false | inherited |
| managed | boolean | — | no | false | inherited |
| protocol | enum | websocket | sse | long-poll | grpc-stream | udp-multicast | no | websocket | ▸ websocket |
| pushFallback | boolean | — | no | false | inherited |
| sequenceNumbers | boolean | — | no | false | inherited |
| stampedeGuard | boolean | — | no | false | inherited |
| stateful | boolean | — | no | true | ▸ true |
| subscriptionsPerUser | integer | — | no | — | inherited |
| transportFallback | boolean | — | no | true | inherited |
Every rule whose selector covers this component's kind or its category. Whether a rule fires depends on the design: its properties, its edges and its groups.
When a gateway holding millions of sockets restarts, every client reconnects at once and the gateway asks the coordination service about each of them. Without a stampede guard that lookup storm takes the coordination service down too.
- — all of these hold:
- — the node has at least one synchronous outgoing edge to a coordination-service
- — the node's `stampedeGuard` is false
With heavy-tail traffic a few channels carry most of the load. Assigning channels at random lands those hot channels on arbitrary hosts, and every tenant sharing a host suffers for it.
- — all of these hold:
- — the node's `channelAssignment` is "random"
- — the design requirement `traffic.skew` is "heavy-tail"
Scaling a gateway down kills every live WebSocket on the removed instance at once. Without a drain step those clients all reconnect together.
- — all of these hold:
- — the node's `autoscaling` is true
- — the node's `drainOnScaleIn` is false
nodes:
- { id: "socket-io-server", component: "socket-io-server" }# yaml-language-server: $schema=../../schema/component.schema.json # Socket.IO server: WebSocket with long-poll fallback. Multi-node needs an adapter (default in-memory) and sticky sessions. schemaVersion: "1" type: "component" id: "socket-io-server" kind: "realtime-gateway" provider: "default" docs: "https://socket.io/docs/v4/" defaults: protocol: "websocket" stateful: true properties: transportFallback: type: "boolean" default: true adapter: type: "enum" values: ["in-memory", "redis", "mongo", "postgres"] default: "in-memory"