Report update progress and log to Hammerhead while updating

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

blacktip.go

@@ -43,7 +43,7 @@ type Config struct {
 	// Hammerhead, by calling UpdateNow (which normally restarts the process into the new binary).
 	Version    string
 	AutoUpdate bool
-	UpdateNow  func(ctx context.Context) (newVersion string, err error)
+	UpdateNow  func(ctx context.Context, progress func(stage string, pct int, line string)) (newVersion string, err error)
 
 	// Traefik, when its Path is set, serves http/https resources instead of the built-in proxy.
 	Traefik TraefikConfig
@@ -116,6 +116,10 @@ type Blacktip struct {
 	updating   atomic.Bool
 	updateMsg  string // outcome of the update Hammerhead asked for, reported back
 	updateID   string // the request that updateMsg answers
+	updStage   string // progress of the running update, reported to Hammerhead
+	updPct     int
+	updLog     []string
+	updSent    time.Time
 	dockerMu   sync.Mutex
 	dockerAt   time.Time
 	dockerList []model.Container
@@ -534,6 +538,7 @@ func (b *Blacktip) report() {
 	}
 	b.mu.Lock()
 	rep.UpdateMsg, rep.UpdateID = b.updateMsg, b.updateID
+	rep.UpdateStage, rep.UpdatePct, rep.UpdateLog = b.updStage, b.updPct, append([]string(nil), b.updLog...)
 	for id, chk := range b.mailChecks {
 		rep.MailChecks[id] = chk
 	}
@@ -760,19 +765,25 @@ func (b *Blacktip) requestUpdate(id string) {
 		return // already handled, or in progress
 	}
 	b.updateID, b.updateMsg = id, ""
+	b.updStage, b.updPct, b.updLog = "starting", 0, nil
+	b.updNote("Update requested from the dashboard")
 	if !b.cfg.AutoUpdate || b.cfg.UpdateNow == nil {
 		b.updateMsg = "auto-update is off on this machine (set BLACKTIP_AUTO_UPDATE=1 and restart it)"
+		b.updStage = "failed"
+		b.updNote("Refused: " + b.updateMsg)
 		go b.report()
 		return
 	}
 	if !b.updating.CompareAndSwap(false, true) {
 		b.updateMsg = "another update is already running"
+		b.updStage = "failed"
+		b.updNote("Refused: " + b.updateMsg)
 		go b.report()
 		return
 	}
 	go func() {
 		defer b.updating.Store(false)
-		tag, err := b.cfg.UpdateNow(b.ctx) // on success this restarts the process and does not return
+		tag, err := b.cfg.UpdateNow(b.ctx, b.updProgress) // on success this restarts the process and does not return
 		b.mu.Lock()
 		switch {
 		case err != nil:
@@ -786,3 +797,32 @@ func (b *Blacktip) requestUpdate(id string) {
 		b.report()
 	}()
 }
+
+// updNote adds a timestamped line to the update log. Caller holds b.mu.
+func (b *Blacktip) updNote(line string) {
+	b.updLog = append(b.updLog, time.Now().Format("15:04:05")+" "+line)
+	if len(b.updLog) > 200 {
+		b.updLog = b.updLog[len(b.updLog)-200:]
+	}
+}
+
+// updProgress is called by the updater as it works; Hammerhead gets a fresh report at most once a
+// second (and straight away for every new log line), so its progress bar follows along.
+func (b *Blacktip) updProgress(stage string, pct int, line string) {
+	b.mu.Lock()
+	b.updStage = stage
+	if pct >= 0 {
+		b.updPct = pct
+	}
+	if line != "" {
+		b.updNote(line)
+	}
+	send := line != "" || time.Since(b.updSent) > time.Second
+	if send {
+		b.updSent = time.Now()
+	}
+	b.mu.Unlock()
+	if send {
+		go b.report()
+	}
+}