108 lines
2.2 KiB
Go
108 lines
2.2 KiB
Go
package main
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import (
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"fmt"
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"net/http"
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"sync"
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"time"
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)
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// sseHub broadcasts events keyed by run_id to N subscribers.
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type sseHub struct {
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mu sync.Mutex
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subscribers map[string]map[chan sseEvent]struct{}
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}
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type sseEvent struct {
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Event string
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Data string
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}
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func newSSEHub() *sseHub {
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return &sseHub{subscribers: make(map[string]map[chan sseEvent]struct{})}
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}
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func (h *sseHub) subscribe(runID string) chan sseEvent {
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ch := make(chan sseEvent, 16)
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h.mu.Lock()
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if _, ok := h.subscribers[runID]; !ok {
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h.subscribers[runID] = make(map[chan sseEvent]struct{})
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}
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h.subscribers[runID][ch] = struct{}{}
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h.mu.Unlock()
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return ch
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}
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func (h *sseHub) unsubscribe(runID string, ch chan sseEvent) {
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h.mu.Lock()
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if subs, ok := h.subscribers[runID]; ok {
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delete(subs, ch)
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if len(subs) == 0 {
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delete(h.subscribers, runID)
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}
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}
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h.mu.Unlock()
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close(ch)
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}
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func (h *sseHub) Publish(runID string, ev sseEvent) {
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h.mu.Lock()
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subs := h.subscribers[runID]
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chans := make([]chan sseEvent, 0, len(subs))
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for c := range subs {
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chans = append(chans, c)
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}
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h.mu.Unlock()
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for _, c := range chans {
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select {
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case c <- ev:
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default:
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// drop on slow subscriber
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}
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}
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}
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func (a *App) handleRunSSE(w http.ResponseWriter, r *http.Request, runID string) {
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w.Header().Set("Content-Type", "text/event-stream")
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w.Header().Set("Cache-Control", "no-cache")
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w.Header().Set("Connection", "keep-alive")
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w.Header().Set("Access-Control-Allow-Origin", "*")
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flusher, ok := w.(http.Flusher)
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if !ok {
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http.Error(w, "streaming unsupported", http.StatusInternalServerError)
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return
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}
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// Subscribe
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ch := a.sse.subscribe(runID)
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defer a.sse.unsubscribe(runID, ch)
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// Send initial connected event
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fmt.Fprintf(w, "event: connected\ndata: {\"run_id\":\"%s\"}\n\n", runID)
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flusher.Flush()
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// Heartbeat + events
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heartbeat := time.NewTicker(15 * time.Second)
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defer heartbeat.Stop()
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for {
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select {
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case <-r.Context().Done():
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return
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case <-heartbeat.C:
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fmt.Fprintf(w, ": heartbeat\n\n")
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flusher.Flush()
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case ev, ok := <-ch:
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if !ok {
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return
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}
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if ev.Event != "" {
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fmt.Fprintf(w, "event: %s\n", ev.Event)
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}
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fmt.Fprintf(w, "data: %s\n\n", ev.Data)
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flusher.Flush()
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}
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}
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}
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