ASP.NET Core SignalR

Self-hosted realtime hub with WebSocket, SSE and long-polling fallback.

Provider
default
Category
Edge
Properties · 5 set by this component
propertytypevaluesrequiredkind defaultthis component
ackIntervalSeconds · advancedinteger—no—inherited
autoscalingboolean—nofalse▸ false
backplane · component propertyenumnone | redis | azure-signalr-servicenononeinherited
channelAssignment · advancedenumrandom | hash | stickynorandom▸ sticky
drainOnScaleIn · advancedboolean—nofalseinherited
hubProtocol · component propertyenumjson | messagepacknojsoninherited
managedboolean—nofalse▸ false
protocolenumwebsocket | sse | long-poll | grpc-stream | udp-multicastnowebsocket▸ websocket
pushFallback · advancedboolean—nofalseinherited
sequenceNumbers · advancedboolean—nofalseinherited
stampedeGuard · advancedboolean—nofalseinherited
statefulboolean—notrue▸ true
stickySessionsRequired · component propertyboolean—notrueinherited
subscriptionsPerUser · advancedinteger—no—inherited
transportFallback · component propertyboolean—notrueinherited
Rules that apply · 3

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.

reconnect-stampede-without-guard

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
shared-host-per-channel-without-isolation

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"
stateful-websocket-scale-in-without-drain

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
Use it in a design
nodes:
  - { id: "signalr", component: "signalr" }
Other Real-time gateway products · 19
Source
# yaml-language-server: $schema=../../schema/component.schema.json
# ASP.NET Core SignalR, self-hosted in your own app. "Overview of ASP.NET Core SignalR" gives the
# transport fallback order WebSockets, Server-Sent Events, long polling with JSON as the default hub
# protocol; "Production hosting and scaling" states the same server must handle every request of a
# connection, so sticky sessions are required on a farm unless a backplane service is used.
schemaVersion: "1"
type: "component"
id: "signalr"
kind: "realtime-gateway"
provider: "default"
docs: "https://learn.microsoft.com/en-us/aspnet/core/signalr/scale"
defaults:
  protocol: "websocket"
  stateful: true
  autoscaling: false
  channelAssignment: "sticky"
  managed: false
properties:
  transportFallback:
    type: "boolean"
    default: true
  stickySessionsRequired:
    type: "boolean"
    default: true
  hubProtocol:
    type: "enum"
    values: ["json", "messagepack"]
    default: "json"
  backplane:
    type: "enum"
    values: ["none", "redis", "azure-signalr-service"]
    default: "none"

The same page as markdown, for an agent: /catalogue/components/signalr.md