3d7302f383
Add server-sent events at GET /api/events for live mutation notifications. Add server mode (normal/read-only/degraded) exposed via /health, /ready, and SSE server.state events. New files: - broker.go: SSE event hub with client management, non-blocking fan-out, ring buffer history for Last-Event-ID replay, heartbeat - servermode.go: mode state machine with periodic MinIO health check and SIGUSR1 read-only toggle - sse_handler.go: HTTP handler using http.Flusher and ResponseController to disable WriteTimeout for long-lived SSE - broker_test.go, servermode_test.go: 13 unit tests Modified: - handlers.go: Server struct gains broker/serverState fields, Health/Ready include mode and sse_clients, write handlers emit item.created/updated/deleted and revision.created events - routes.go: register GET /api/events, add RequireWritable middleware to all 8 editor-gated route groups - middleware.go: RequireWritable returns 503 in read-only mode - csv.go, ods.go: emit bulk item.created events after import - storage.go: add Ping() method for health checks - config.go: add ReadOnly field to ServerConfig - main.go: create broker/state, start background goroutines, SIGUSR1 handler, graceful shutdown sequence Closes #38, closes #39
62 lines
1.7 KiB
Go
62 lines
1.7 KiB
Go
package api
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import (
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"fmt"
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"net/http"
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"strconv"
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"time"
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)
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// HandleEvents serves the SSE event stream.
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// GET /api/events (requires auth, viewer+)
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func (s *Server) HandleEvents(w http.ResponseWriter, r *http.Request) {
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flusher, ok := w.(http.Flusher)
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if !ok {
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writeError(w, http.StatusInternalServerError, "streaming_unsupported", "Streaming not supported")
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return
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}
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// Disable the write deadline for this long-lived connection.
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// The server's WriteTimeout (15s) would otherwise kill it.
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rc := http.NewResponseController(w)
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if err := rc.SetWriteDeadline(time.Time{}); err != nil {
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s.logger.Warn().Err(err).Msg("failed to disable write deadline for SSE")
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}
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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("X-Accel-Buffering", "no") // nginx: disable proxy buffering
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client := s.broker.Subscribe()
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defer s.broker.Unsubscribe(client)
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// Replay missed events if Last-Event-ID is present.
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if lastIDStr := r.Header.Get("Last-Event-ID"); lastIDStr != "" {
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if lastID, err := strconv.ParseUint(lastIDStr, 10, 64); err == nil {
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for _, ev := range s.broker.EventsSince(lastID) {
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fmt.Fprintf(w, "id: %d\nevent: %s\ndata: %s\n\n", ev.ID, ev.Type, ev.Data)
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}
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flusher.Flush()
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}
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}
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// Send initial server.state event.
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fmt.Fprintf(w, "event: server.state\ndata: %s\n\n",
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mustMarshal(map[string]string{"mode": string(s.serverState.Mode())}))
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flusher.Flush()
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// Stream loop.
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for {
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select {
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case ev := <-client.ch:
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fmt.Fprintf(w, "id: %d\nevent: %s\ndata: %s\n\n", ev.ID, ev.Type, ev.Data)
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flusher.Flush()
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case <-client.closed:
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return
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case <-r.Context().Done():
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return
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}
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}
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}
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