Build SSE

Build SSE

Adds server-sent events for real-time updates (job status, notifications, live data).

Inputs

Confirm with user:

• streamName — what is being streamed? (e.g. job-status, notifications, analytics)
• Event types — what events will be sent?
• Who receives events? (per-user or broadcast)

Steps

1. Read go-stack: pattern://sse-streaming.md

2. Write internal/services/broker.go — event broker:

   type Broker struct {
       clients    map[string][]chan Event  // userID → channels
       subscribe  chan subscription
       unsubscribe chan subscription
       publish    chan Event
   }
   

   • Start() — goroutine that manages client channels
   • Subscribe(userID) → chan Event
   • Unsubscribe(userID, ch)
   • Publish(userID, event) or Broadcast(event)

3. Write SSE handler in internal/handlers/sse.go:

   func (h *Handler) Events(w http.ResponseWriter, r *http.Request) {
       w.Header().Set("Content-Type", "text/event-stream")
       w.Header().Set("Cache-Control", "no-cache")
       w.Header().Set("Connection", "keep-alive")
       // subscribe, stream events, handle disconnect
   }
   

4. Write internal/ui/components/sse_listener.templ:

   • HTMX SSE extension: <div hx-ext="sse" hx-sse="connect:/api/sse">
   • Event listener elements: <div hx-sse="swap:{event-name}">

5. Register GET /api/sse in cmd/server/main.go (behind RequireAuth)

6. Initialize broker in main.go and inject into relevant services that need to emit events

7. Add heartbeat tick (every 30s) to keep connection alive through proxies

8. Run go build ./... + templ generate

Success Criteria

• go build ./... passes
• GET /api/sse returns Content-Type: text/event-stream
• Broker fan-out works: publishing to a userID sends to all that user's open connections
• Heartbeat keeps connections alive