fix: make web updates restart cleanly

Dockerfile

@@ -1,20 +1,25 @@
 # syntax=docker/dockerfile:1.7
 
-# ---- Stage 1: build the web frontend ----
-FROM node:20-alpine AS web-builder
+# Build toolchains run natively on the BuildKit host. Without BUILDPLATFORM,
+# the arm64 branch executes npm and the Go compiler through QEMU, which is much
+# slower and makes npm ci appear to hang despite producing no progress output.
+# ---- Stage 1: build the web frontend once on the native builder ----
+FROM --platform=$BUILDPLATFORM node:20-alpine AS web-builder
 WORKDIR /web
 COPY web/package.json web/package-lock.json* ./
 RUN npm ci
 COPY web/ ./
 RUN npm run build
 
-# ---- Stage 2: build the Go binary ----
-FROM golang:1.25-alpine AS go-builder
+# ---- Stage 2: cross-compile the Go binary on the native builder ----
+FROM --platform=$BUILDPLATFORM golang:1.25-alpine AS go-builder
 RUN apk add --no-cache git
 WORKDIR /src
 
 ARG VERSION=0.1.0-dev
 ARG BUILD_TIME=""
+ARG TARGETOS
+ARG TARGETARCH
 
 COPY go.mod go.sum ./
 RUN go mod download
@@ -23,7 +28,7 @@ COPY . .
 # Overlay the freshly built frontend so go:embed web/dist picks it up.
 COPY --from=web-builder /web/dist ./web/dist
 
-RUN CGO_ENABLED=0 GOOS=linux go build \
+RUN CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH} go build \
     -trimpath \
     -ldflags "-s -w -X vocat/internal/buildinfo.Version=${VERSION} -X vocat/internal/buildinfo.BuildTime=${BUILD_TIME}" \
     -o /out/vocat \

cmd/vocat/main.go

@@ -248,6 +248,10 @@ func run(logger *slog.Logger, logs *loghub.Hub) error {
 	case <-signalContext.Done():
 		logger.Info("shutdown signal received")
 	}
+	// Long-lived SSE and polling handlers use this context. Stop them before
+	// http.Server.Shutdown so they do not consume the entire graceful-shutdown
+	// deadline while waiting for a stream that is intentionally still active.
+	cancelPolling()
 
 	shutdownContext, cancelShutdown := context.WithTimeout(
 		context.Background(),

internal/update/update.go

@@ -7,8 +7,8 @@
 // Trust model: GitHub TLS guarantees the channel; the repository owner controls
 // which assets are published; SHA256SUMS guards integrity. There is no GPG
 // signature verification — an accepted trade-off for a closed-network testing
-// tool. The web UI's check-update button remains an intentional no-op; only the
-// CLI performs code replacement.
+// tool. Both the CLI and authenticated web UI use this same verified replacement
+// path.
 package update
 
 import (
@@ -232,7 +232,10 @@ func RestartService(logger *slog.Logger) error {
 	if _, err := exec.LookPath("systemctl"); err != nil {
 		return fmt.Errorf("systemctl not found in PATH")
 	}
-	cmd := exec.Command("systemctl", "restart", "vocat")
+	// Queue the restart and let systemctl exit before systemd stops this unit.
+	// A blocking restart command becomes part of vocat.service's own cgroup and
+	// waits for that same cgroup to terminate, creating a stop-timeout cycle.
+	cmd := exec.Command("systemctl", "restart", "--no-block", "vocat")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		logger.Warn("systemctl restart failed", "error", err, "output", string(out))
 		return fmt.Errorf("systemctl restart vocat: %w", err)

scripts/install.sh

@@ -216,7 +216,9 @@ ExecStart=${BINARY_PATH}
 Restart=on-failure
 RestartSec=3s
 TimeoutStartSec=30s
-TimeoutStopSec=20s
+# HTTP, VoWiFi, and modem cleanup have bounded shutdown contexts totalling up
+# to 30 seconds. Leave a small margin before systemd resorts to SIGKILL.
+TimeoutStopSec=40s
 
 AmbientCapabilities=CAP_NET_ADMIN CAP_NET_RAW
 CapabilityBoundingSet=CAP_NET_ADMIN CAP_NET_RAW
@@ -229,7 +231,9 @@ ProtectKernelLogs=true
 ProtectKernelModules=true
 ProtectKernelTunables=true
 ProtectControlGroups=true
-ReadWritePaths=/opt/vocat/data
+# The web/CLI self-updater verifies a release in this directory and atomically
+# renames it over the running binary. Keep the rest of the host read-only.
+ReadWritePaths=/opt/vocat/data /opt/vocat/bin
 RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6 AF_NETLINK
 RestrictRealtime=true
 LockPersonality=true