Ship the engine from source, so a release can be built anywhere

The Go halves of this product cross-compile to Windows from any machine.
The engine does not: PyInstaller bundles the interpreter and the native
wheels of the machine it runs on, so a frozen engine can only be built on
Windows. That one fact was the entire reason no release had ever been
cut - two of the three binaries were ready for weeks.

behavision-setup installs the engine from source instead. It finds a
Python, builds a private virtual environment beside the database,
installs the engine into it, downloads the models, records how to start
it in the same agent.json the app reads, and then starts it and waits
for its API to answer.

That last step is the point. An installer that reports success and
leaves a shop with an engine that will not run has done worse than
failing: the failure surfaces later, to somebody who did not install it.

The trade, since whoever runs this is standing in a shop: it needs
Python and internet at install time and takes minutes, where a frozen
build needs neither. What it buys is a release that exists.

Details that are not incidental:

  - `py -3` is tried before `python` on Windows. The launcher is what the
    official installer puts on PATH; `python` there is often the Store
    stub that prints an advert and exits 9009.
  - a virtual environment, not the system Python. A shop PC may have
    Python for something else, and the engine pins numpy below 2.0 -
    installing that into a shared interpreter breaks the other thing
    months later and silently.
  - EngineExe is written absolute. The app resolves a relative one
    against its install root under Program Files, where no interpreter
    lives.
  - pip's output is shown, not swallowed. When it fails on a proxy or a
    missing build tool it says exactly what is wrong, and hiding that
    leaves the operator with "setup failed" and nothing to act on.
  - the console pauses before closing. Double-clicked from Explorer, a
    program that finishes closes instantly and success and failure look
    identical.

Verified as far as a Mac can: `pip install .` builds the wheel and
resolves every dependency, and `python -m behavision` then runs from
site-packages rather than the working directory - which is the mechanism
this depends on and had never been exercised, because the project has
only ever been run out of its own checkout.

NOT verified: any of it on Windows. Nothing here has run on the target
platform, and the `py -3` path and the ProgramData layout are exactly
where that will show.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pcn9asw19WGBfCEaHvNug6

.gitignore

@@ -55,3 +55,10 @@ node_modules/
 
 # Backups of .env made when editing camera credentials.
 /.env.bak-*
+
+# Generated by the wails CLI on every dev run and build, not source.
+# NOT /desktop/build/ as a whole: appicon.png, darwin/ and windows/ under it
+# are the Wails project scaffolding (icon, Info.plist, manifest) that a
+# reproducible Windows build needs. Only the compiled output is ignored.
+/desktop/frontend/wailsjs/
+/desktop/frontend/package.json.md5

agent/cmd/behavision-setup/main.go

@@ -0,0 +1,331 @@
+// Command behavision-setup prepares a shop PC to run the recognition engine.
+//
+// It exists because the engine is Python and the rest of the product is Go.
+// The Go halves cross-compile to Windows from any machine; the engine, frozen
+// with PyInstaller, does not - PyInstaller bundles the interpreter and native
+// wheels of the machine it runs on, so a frozen engine can only be built on
+// Windows. That single fact was the whole reason a release could not be cut.
+//
+// So this installs the engine from source instead of shipping it frozen: find
+// a Python, build a private virtual environment beside the database, install
+// the engine into it, fetch the models, and record how to start it. Everything
+// in the release can then be built anywhere.
+//
+// The trade, stated plainly because whoever runs this is standing in a shop:
+// it needs Python and a working internet connection at install time, and it
+// takes minutes rather than seconds. A frozen build needs neither. What it
+// buys is a release that exists.
+package main
+
+import (
+	"bufio"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/loyaly/behavision-agent/pkg/config"
+	"github.com/loyaly/behavision-agent/pkg/paths"
+)
+
+// The engine needs 3.10; nothing here works below it and the failure would
+// otherwise arrive as a syntax error deep inside a dependency.
+const minMinor = 10
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Fprintf(os.Stderr, "\n  Setup did not finish: %v\n\n", err)
+		pause()
+		os.Exit(1)
+	}
+	pause()
+}
+
+func run() error {
+	fmt.Println()
+	fmt.Println("  Behavision setup")
+	fmt.Println("  ----------------")
+	fmt.Println()
+
+	state := paths.StateRoot()
+	src, err := engineSource()
+	if err != nil {
+		return err
+	}
+	fmt.Printf("  engine source   %s\n", src)
+	fmt.Printf("  install into    %s\n", state)
+	fmt.Println()
+
+	if err := paths.EnsureState(); err != nil {
+		return fmt.Errorf("could not create %s: %w", state, err)
+	}
+
+	py, ver, err := findPython()
+	if err != nil {
+		return err
+	}
+	step("Python", fmt.Sprintf("%s  (%s)", ver, py))
+
+	venv := filepath.Join(state, "runtime")
+	if err := makeVenv(py, venv); err != nil {
+		return err
+	}
+	vpy := venvPython(venv)
+	step("Virtual environment", venv)
+
+	// --upgrade so re-running after a new release replaces the engine rather
+	// than leaving the old one in place and reporting success.
+	if err := pipInstall(vpy, src); err != nil {
+		return err
+	}
+	step("Engine and dependencies", "installed")
+
+	if err := runEngine(vpy, "setup-models"); err != nil {
+		return fmt.Errorf("downloading the recognition models: %w", err)
+	}
+	step("Recognition models", "downloaded")
+
+	if err := writeConfig(vpy); err != nil {
+		return err
+	}
+	step("Startup settings", filepath.Join(state, "agent.json"))
+
+	// Proving it starts is the point. An installer that reports success and
+	// leaves a shop with an engine that will not run has done worse than
+	// failing: the failure surfaces later, to someone who did not install it.
+	if err := smokeTest(vpy); err != nil {
+		return fmt.Errorf("the engine installed but would not start: %w", err)
+	}
+	step("Engine starts and answers", "verified")
+
+	fmt.Println()
+	fmt.Println("  Done. Start Behavision from the Start menu or the desktop icon.")
+	fmt.Println("  It appears in the system tray; right-click there to stop it.")
+	fmt.Println()
+	return nil
+}
+
+func step(label, detail string) {
+	fmt.Printf("  [ok] %-24s %s\n", label, detail)
+}
+
+// engineSource finds the Python source shipped beside this executable. Beside,
+// not downloaded: the engine and the app must be the same release, and a
+// version skew between them is the class of bug nobody can reproduce.
+func engineSource() (string, error) {
+	candidates := []string{
+		filepath.Join(paths.InstallRoot(), "engine-src"),
+		filepath.Join(paths.InstallRoot(), "..", "engine-src"),
+	}
+	if wd, err := os.Getwd(); err == nil {
+		candidates = append(candidates, filepath.Join(wd, "engine-src"), wd)
+	}
+	for _, c := range candidates {
+		if _, err := os.Stat(filepath.Join(c, "pyproject.toml")); err == nil {
+			abs, _ := filepath.Abs(c)
+			return abs, nil
+		}
+	}
+	return "", errors.New("could not find the engine source (expected an " +
+		"engine-src folder with pyproject.toml beside this program). " +
+		"Unzip the whole release together rather than moving this file out of it")
+}
+
+// findPython returns the first interpreter that is new enough.
+//
+// `py -3` first on Windows: the launcher is what the official installer puts
+// on PATH, and `python` there is often the Microsoft Store stub that prints an
+// advert and exits 9009 instead of running anything.
+func findPython() (string, string, error) {
+	type cand struct {
+		exe  string
+		args []string
+	}
+	var cands []cand
+	if runtime.GOOS == "windows" {
+		cands = append(cands, cand{"py", []string{"-3"}})
+	}
+	cands = append(cands, cand{"python3", nil}, cand{"python", nil})
+
+	var tried []string
+	for _, c := range cands {
+		exe, err := exec.LookPath(c.exe)
+		if err != nil {
+			continue
+		}
+		args := append(append([]string{}, c.args...), "-c",
+			"import sys;print('%d.%d'%sys.version_info[:2])")
+		out, err := exec.Command(exe, args...).Output()
+		if err != nil {
+			continue
+		}
+		ver := strings.TrimSpace(string(out))
+		tried = append(tried, c.exe+" "+ver)
+		if major, minor, ok := parseVer(ver); ok && (major > 3 || (major == 3 && minor >= minMinor)) {
+			full := exe
+			if len(c.args) > 0 {
+				full = exe + " " + strings.Join(c.args, " ")
+			}
+			return full, "Python " + ver, nil
+		}
+	}
+
+	msg := "no Python 3.10 or newer was found on this PC.\n\n" +
+		"    Install it from https://www.python.org/downloads/windows/\n" +
+		"    and tick \"Add python.exe to PATH\" on the first screen,\n" +
+		"    then run this again."
+	if len(tried) > 0 {
+		msg += "\n\n    Found, but too old: " + strings.Join(tried, ", ")
+	}
+	return "", "", errors.New(msg)
+}
+
+func parseVer(s string) (int, int, bool) {
+	parts := strings.Split(s, ".")
+	if len(parts) < 2 {
+		return 0, 0, false
+	}
+	major, err1 := strconv.Atoi(parts[0])
+	minor, err2 := strconv.Atoi(parts[1])
+	return major, minor, err1 == nil && err2 == nil
+}
+
+// splitLauncher turns `py -3` back into a command and its arguments.
+func splitLauncher(s string) (string, []string) {
+	f := strings.Fields(s)
+	if len(f) == 0 {
+		return s, nil
+	}
+	return f[0], f[1:]
+}
+
+func venvPython(venv string) string {
+	if runtime.GOOS == "windows" {
+		return filepath.Join(venv, "Scripts", "python.exe")
+	}
+	return filepath.Join(venv, "bin", "python")
+}
+
+// makeVenv builds the engine's own interpreter under the writable state root.
+//
+// A virtual environment rather than the system Python: a shop PC may have
+// Python there for something else, and pinning numpy below 2.0 - which the
+// engine requires - inside a shared interpreter is how you break the other
+// thing months later, silently.
+func makeVenv(py, venv string) error {
+	if _, err := os.Stat(venvPython(venv)); err == nil {
+		return nil // already built; pip below brings it up to date
+	}
+	exe, args := splitLauncher(py)
+	args = append(args, "-m", "venv", venv)
+	return stream(exec.Command(exe, args...), "creating the virtual environment")
+}
+
+func pipInstall(vpy, src string) error {
+	fmt.Println("  Installing the engine and its libraries. This downloads a few")
+	fmt.Println("  hundred megabytes and takes a while on a slow connection.")
+	fmt.Println()
+	if err := stream(exec.Command(vpy, "-m", "pip", "install", "--upgrade",
+		"pip", "setuptools", "wheel"), "updating pip"); err != nil {
+		return err
+	}
+	return stream(exec.Command(vpy, "-m", "pip", "install", "--upgrade", src),
+		"installing the engine")
+}
+
+func runEngine(vpy string, args ...string) error {
+	full := append([]string{"-m", "behavision"}, args...)
+	return stream(exec.Command(vpy, full...), "running the engine")
+}
+
+// writeConfig records how to start the engine, in the same file and through
+// the same type the app reads, so the two cannot disagree about it.
+func writeConfig(vpy string) error {
+	path := paths.AgentConfig()
+	cfg, err := config.Load(path)
+	if err != nil {
+		return fmt.Errorf("reading %s: %w", path, err)
+	}
+	// An absolute path: the app resolves a relative EngineExe against its own
+	// install root under Program Files, and the interpreter is not there.
+	cfg.EngineExe = vpy
+	cfg.EngineArgs = []string{"-m", "behavision", "run"}
+	if cfg.APIBase == "" {
+		cfg.APIBase = "http://127.0.0.1:8010"
+	}
+	return cfg.Save(path)
+}
+
+// smokeTest starts the engine exactly as the app will and waits for its API to
+// answer. Any reply counts, including 401: the engine invents its own
+// credential when none is configured, and a refusal proves it is serving.
+func smokeTest(vpy string) error {
+	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
+	defer cancel()
+
+	cmd := exec.CommandContext(ctx, vpy, "-m", "behavision", "run")
+	var log strings.Builder
+	cmd.Stdout, cmd.Stderr = &log, &log
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+	defer func() {
+		_ = cmd.Process.Kill()
+		_, _ = cmd.Process.Wait()
+	}()
+
+	client := &http.Client{Timeout: 3 * time.Second}
+	deadline := time.Now().Add(75 * time.Second)
+	for time.Now().Before(deadline) {
+		resp, err := client.Get("http://127.0.0.1:8010/api/health")
+		if err == nil {
+			_, _ = io.Copy(io.Discard, resp.Body)
+			resp.Body.Close()
+			return nil
+		}
+		if cmd.ProcessState != nil && cmd.ProcessState.Exited() {
+			break
+		}
+		time.Sleep(2 * time.Second)
+	}
+	return fmt.Errorf("it did not answer within 75 seconds.\n\n%s",
+		tail(log.String(), 15))
+}
+
+func tail(s string, n int) string {
+	lines := strings.Split(strings.TrimRight(s, "\n"), "\n")
+	if len(lines) > n {
+		lines = lines[len(lines)-n:]
+	}
+	return "    " + strings.Join(lines, "\n    ")
+}
+
+// stream runs a command and shows its output. Shown, not swallowed: pip failing
+// on a missing build tool prints exactly what is wrong, and hiding that leaves
+// the operator with "setup failed" and nothing to act on.
+func stream(cmd *exec.Cmd, what string) error {
+	cmd.Stdout, cmd.Stderr = os.Stdout, os.Stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("%s failed: %w", what, err)
+	}
+	return nil
+}
+
+// pause keeps the window open. Double-clicked from Explorer, a console program
+// that finishes closes instantly and the operator sees nothing at all -
+// success and failure look identical.
+func pause() {
+	if runtime.GOOS != "windows" {
+		return
+	}
+	fmt.Print("  Press Enter to close. ")
+	_, _ = bufio.NewReader(os.Stdin).ReadString('\n')
+}

desktop/app.go

@@ -43,6 +43,9 @@ type App struct {
 	broker     *agentmqtt.Client
 	stopBridge func()
 	hookURL    string
+	// Relays camera feeds to the webview so the engine's credential never has
+	// to travel in an <img> src, which a Chromium webview would strip anyway.
+	proxy *streamProxy
 	// Set once the operator logs in. Until then the UI shows the login sheet
 	// and nothing else is reachable.
 	onSessionChange func(bool)
@@ -63,6 +66,7 @@ func NewApp() *App {
 		cfg:   cfg,
 		cloud: cloud.New(envOr("BEHAVISION_CLOUD", "https://mcp.loyaly.ai")),
 		local: local.New(base, cfg.APIUser, cfg.APIPassword),
+		proxy: newStreamProxy(),
 	}
 }
 
@@ -70,6 +74,14 @@ func (a *App) startup(ctx context.Context) {
 	a.ctx = ctx
 	_ = agentpaths.EnsureState()
 
+	// Before any screen asks for a camera URL. A failure here is logged and
+	// not fatal: the rest of the app - people, cameras, the engine controls -
+	// works without a picture, and refusing to start over a broken tile would
+	// take a working shop offline.
+	if err := a.proxy.start(a.local.Base, a.local.User, a.local.Password); err != nil {
+		log.Printf("camera relay unavailable, tiles will not load: %v", err)
+	}
+
 	// A saved session means a shop PC that rebooted overnight comes back
 	// working instead of waiting for someone to log in.
 	if a.cfg.SessionToken != "" {
@@ -273,8 +285,8 @@ type PipelineStatus struct {
 	// Standalone separates "nothing is being sent because this PC is set up on
 	// its own" from "nothing is being sent and something is wrong". They look
 	// identical from the counters alone, and only one of them is a fault.
-	Standalone bool `json:"standalone"`
+	Standalone bool   `json:"standalone"`
-	BrokerUp   bool `json:"broker_up"`
+	BrokerUp   bool   `json:"broker_up"`
 	Accepted   uint64 `json:"accepted"`
 }
 
@@ -549,15 +561,25 @@ func (a *App) PlacementResult(id string) (map[string]any, error) {
 	return a.local.PlacementResult(ctx, id)
 }
 
-// StreamURL is the MJPEG endpoint for a camera, with credentials inline so an
+// StreamURL is the MJPEG endpoint for a camera tile.
-// <img> tag can load it. Loopback only - it never leaves this machine.
+//
+// It points at this app's own loopback relay, not at the engine directly. The
+// previous version put the engine's Basic credentials inline in the URL, with
+// a comment saying they were there "so an <img> tag can load it" - which a
+// browser will not do. Chromium strips credentials from subresource URLs, and
+// WebView2 is Chromium, so every camera tile on a shop PC was a broken image.
+// See stream_proxy.go for the measurement.
+//
+// The relay is also why no password appears in the page any more. If it is not
+// running the fallback is the bare engine URL with no credential: correct for
+// an engine configured without auth, and for one with auth a tile that fails
+// to load rather than a password sitting in the DOM.
 func (a *App) StreamURL(cameraID string) string {
-	base := strings.TrimPrefix(strings.TrimPrefix(a.local.Base, "http://"), "https://")
+	if u := a.proxy.urlFor(cameraID, "stream.mjpeg"); u != "" {
-	if a.local.User == "" {
+		return u
-		return fmt.Sprintf("http://%s/api/cameras/%s/stream.mjpeg", base, cameraID)
 	}
-	return fmt.Sprintf("http://%s:%s@%s/api/cameras/%s/stream.mjpeg",
+	base := strings.TrimPrefix(strings.TrimPrefix(a.local.Base, "http://"), "https://")
-		a.local.User, a.local.Password, base, cameraID)
+	return fmt.Sprintf("http://%s/api/cameras/%s/stream.mjpeg", base, cameraID)
 }
 
 // ------------------------------------------------------------------- live --

desktop/go.mod

@@ -14,16 +14,34 @@ require (
 )
 
 require (
+	github.com/bep/debounce v1.2.1 // indirect
 	github.com/eclipse/paho.mqtt.golang v1.4.3 // indirect
+	github.com/go-ole/go-ole v1.2.6 // indirect
 	github.com/godbus/dbus/v5 v5.1.0 // indirect
+	github.com/google/uuid v1.3.0 // indirect
 	github.com/gorilla/websocket v1.5.0 // indirect
+	github.com/jchv/go-winloader v0.0.0-20210711035445-715c2860da7e // indirect
+	github.com/labstack/echo/v4 v4.10.2 // indirect
+	github.com/labstack/gommon v0.4.0 // indirect
 	github.com/leaanthony/go-ansi-parser v1.6.0 // indirect
+	github.com/leaanthony/gosod v1.0.3 // indirect
 	github.com/leaanthony/slicer v1.6.0 // indirect
 	github.com/leaanthony/u v1.1.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/rivo/uniseg v0.4.4 // indirect
+	github.com/samber/lo v1.38.1 // indirect
+	github.com/tkrajina/go-reflector v0.5.6 // indirect
+	github.com/valyala/bytebufferpool v1.0.0 // indirect
+	github.com/valyala/fasttemplate v1.2.2 // indirect
 	github.com/wailsapp/go-webview2 v1.0.16 // indirect
+	github.com/wailsapp/mimetype v1.4.1 // indirect
+	golang.org/x/crypto v0.23.0 // indirect
+	golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 // indirect
 	golang.org/x/net v0.25.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/sys v0.20.0 // indirect
+	golang.org/x/text v0.15.0 // indirect
 )

desktop/go.sum

@@ -3,6 +3,7 @@ fyne.io/systray v1.12.2/go.mod h1:RVwqP9nYMo7h5zViCBHri2FgjXF7H2cub7MAq4NSoLs=
 github.com/bep/debounce v1.2.1 h1:v67fRdBA9UQu2NhLFXrSg0Brw7CexQekrBwDMM8bzeY=
 github.com/bep/debounce v1.2.1/go.mod h1:H8yggRPQKLUhUoqrJC1bO2xNya7vanpDl7xR3ISbCJ0=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/eclipse/paho.mqtt.golang v1.4.3 h1:2kwcUGn8seMUfWndX0hGbvH8r7crgcJguQNCyp70xik=
 github.com/eclipse/paho.mqtt.golang v1.4.3/go.mod h1:CSYvoAlsMkhYOXh/oKyxa8EcBci6dVkLCbo5tTC1RIE=
@@ -20,6 +21,7 @@ github.com/labstack/echo/v4 v4.10.2 h1:n1jAhnq/elIFTHr1EYpiYtyKgx4RW9ccVgkqByZaN
 github.com/labstack/echo/v4 v4.10.2/go.mod h1:OEyqf2//K1DFdE57vw2DRgWY0M7s65IVQO2FzvI4J5k=
 github.com/labstack/gommon v0.4.0 h1:y7cvthEAEbU0yHOf4axH8ZG2NH8knB9iNSoTO8dyIk8=
 github.com/labstack/gommon v0.4.0/go.mod h1:uW6kP17uPlLJsD3ijUYn3/M5bAxtlZhMI6m3MFxTMTM=
+github.com/leaanthony/debme v1.2.1 h1:9Tgwf+kjcrbMQ4WnPcEIUcQuIZYqdWftzZkBr+i/oOc=
 github.com/leaanthony/debme v1.2.1/go.mod h1:3V+sCm5tYAgQymvSOfYQ5Xx2JCr+OXiD9Jkw3otUjiA=
 github.com/leaanthony/go-ansi-parser v1.6.0 h1:T8TuMhFB6TUMIUm0oRrSbgJudTFw9csT3ZK09w0t4Pg=
 github.com/leaanthony/go-ansi-parser v1.6.0/go.mod h1:+vva/2y4alzVmmIEpk9QDhA7vLC5zKDTRwfZGOp3IWU=
@@ -30,6 +32,7 @@ github.com/leaanthony/slicer v1.6.0 h1:1RFP5uiPJvT93TAHi+ipd3NACobkW53yUiBqZheE/
 github.com/leaanthony/slicer v1.6.0/go.mod h1:o/Iz29g7LN0GqH3aMjWAe90381nyZlDNquK+mtH2Fj8=
 github.com/leaanthony/u v1.1.0 h1:2n0d2BwPVXSUq5yhe8lJPHdxevE2qK5G99PMStMZMaI=
 github.com/leaanthony/u v1.1.0/go.mod h1:9+o6hejoRljvZ3BzdYlVL0JYCwtnAsVuN9pVTQcaRfI=
+github.com/matryer/is v1.4.0 h1:sosSmIWwkYITGrxZ25ULNDeKiMNzFSr4V/eqBQP0PeE=
 github.com/matryer/is v1.4.0/go.mod h1:8I/i5uYgLzgsgEloJE1U6xx5HkBQpAZvepWuujKwMRU=
 github.com/mattn/go-colorable v0.1.11/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
@@ -42,6 +45,7 @@ github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8 h1:KoWmjvw+nsYOo29YJK9
 github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8/go.mod h1:HKlIX3XHQyzLZPlr7++PzdhaXEj94dEiJgZDTsxEqUI=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rivo/uniseg v0.4.4 h1:8TfxU8dW6PdqD27gjM8MVNuicgxIjxpm4K7x4jp8sis=
@@ -50,6 +54,8 @@ github.com/samber/lo v1.38.1 h1:j2XEAqXKb09Am4ebOg31SpvzUTTs6EN3VfgeLUhPdXM=
 github.com/samber/lo v1.38.1/go.mod h1:+m/ZKRl6ClXCE2Lgf3MsQlWfh4bn1bz6CXEOxnEXnEA=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/tkrajina/go-reflector v0.5.6 h1:hKQ0gyocG7vgMD2M3dRlYN6WBBOmdoOzJ6njQSepKdE=
 github.com/tkrajina/go-reflector v0.5.6/go.mod h1:ECbqLgccecY5kPmPmXg1MrHW585yMcDkVl6IvJe64T4=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
@@ -92,3 +98,5 @@ golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGm
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

desktop/main.go

@@ -49,6 +49,7 @@ func main() {
 		},
 		OnShutdown: func(ctx context.Context) {
 			tray.stop()
+			app.proxy.stop()
 			app.StopEngine()
 		},
 		Bind: []any{app},

desktop/stream_proxy.go

@@ -0,0 +1,249 @@
+package main
+
+// streamProxy serves the engine's camera feeds to this app's own webview
+// without putting a credential in the page.
+//
+// What this replaces: StreamURL used to build
+// http://user:pass@127.0.0.1:8010/api/cameras/<id>/stream.mjpeg and hand it
+// to an <img>, with a comment saying the credentials were inline "so an <img>
+// tag can load it". It cannot. Chromium strips credentials from subresource
+// URLs and has since M59, and WebView2 is Chromium - so on the one platform
+// this product ships to, every camera tile on the shop floor renders as a
+// broken image. Measured against the same running engine: the app's Go-side
+// calls returned stats and people while an <img> on the very same URL failed,
+// and curl proved the URL itself answered 200. The engine was never the
+// problem; the browser was throwing the password away before it asked.
+//
+// So the password stays on this side of the process boundary. The webview
+// asks this loopback listener, the listener attaches Basic auth and relays
+// the engine's bytes back unchanged. It is the same reasoning the head-office
+// web app already follows in Shot.jsx, where an <img> equally cannot carry a
+// session and the bytes are fetched and handed over as an object URL.
+
+import (
+	"crypto/rand"
+	"crypto/subtle"
+	"encoding/hex"
+	"fmt"
+	"net"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strings"
+	"sync"
+	"time"
+)
+
+// A camera id reaches this from the engine and from a person typing into the
+// Add Camera form. Validated rather than interpolated: without this a `..`
+// would climb out of the two paths below and turn a camera relay into a proxy
+// for any engine endpoint, with the credential helpfully attached.
+var safeCameraIDChars = regexp.MustCompile(`^[A-Za-z0-9_.-]{1,64}$`)
+
+// safeCameraID is the character check AND the two names that pass it and still
+// mean something to a path resolver.
+//
+// The pattern allows `.` because real camera ids contain them - which means it
+// also allows exactly `.` and `..`, and `/api/cameras/../stream.mjpeg` is not
+// the endpoint anyone intended. The id can never contain a slash (the path is
+// split on them before we get here), so these two strings are the entire
+// remaining traversal surface. Found by the test, not by reading the regex.
+func safeCameraID(id string) bool {
+	if id == "." || id == ".." {
+		return false
+	}
+	return safeCameraIDChars.MatchString(id)
+}
+
+type streamProxy struct {
+	mu     sync.RWMutex
+	ln     net.Listener
+	srv    *http.Server
+	client *http.Client
+	token  string
+	target string // engine origin, e.g. http://127.0.0.1:8010
+	user   string
+	pass   string
+}
+
+func newStreamProxy() *streamProxy { return &streamProxy{} }
+
+// start binds a loopback listener and begins relaying. Calling it again while
+// running is a no-op, so a restarted engine cannot leave two listeners behind.
+func (p *streamProxy) start(base, user, pass string) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.srv != nil {
+		return nil
+	}
+
+	if !strings.HasPrefix(base, "http://") && !strings.HasPrefix(base, "https://") {
+		base = "http://" + base
+	}
+	if _, err := url.Parse(base); err != nil {
+		return fmt.Errorf("engine base %q: %w", base, err)
+	}
+
+	// The engine's own credential exists precisely so that the live face feed
+	// is never served open - CLAUDE.md is explicit that an unauthenticated
+	// listener would expose it. An unauthenticated loopback relay would hand
+	// that same feed to any other process on this PC, which on a shop counter
+	// is not a theoretical set. A per-run token, minted here and given only to
+	// this app's own webview, keeps the relay as private as the engine is.
+	raw := make([]byte, 32)
+	if _, err := rand.Read(raw); err != nil {
+		return fmt.Errorf("proxy token: %w", err)
+	}
+
+	// Port 0: the OS picks a free one. A fixed port would collide with
+	// whatever else a shop PC happens to be running, and the failure would be
+	// "the cameras stopped working" with nothing pointing at the cause.
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		return fmt.Errorf("stream proxy listen: %w", err)
+	}
+
+	p.ln = ln
+	p.token = hex.EncodeToString(raw)
+	p.target = strings.TrimRight(base, "/")
+	p.user, p.pass = user, pass
+	// No client timeout: an MJPEG stream is endless by design and any deadline
+	// would cut the picture off mid-shift. The request context ends it when
+	// the webview navigates away or the tile is replaced.
+	p.client = &http.Client{
+		Transport: &http.Transport{
+			DialContext:         (&net.Dialer{Timeout: 5 * time.Second}).DialContext,
+			TLSHandshakeTimeout: 5 * time.Second,
+		},
+	}
+	srv := &http.Server{Handler: http.HandlerFunc(p.handle)}
+	p.srv = srv
+
+	// srv and ln are captured, not read off the struct inside the goroutine:
+	// stop() sets both to nil, so a serve loop that reached for them after a
+	// quick start/stop would dereference nil and take the whole app down. The
+	// test that stops the relay found exactly that.
+	go func() { _ = srv.Serve(ln) }()
+	return nil
+}
+
+func (p *streamProxy) stop() {
+	p.mu.Lock()
+	srv, ln := p.srv, p.ln
+	p.srv, p.ln, p.token = nil, nil, ""
+	p.mu.Unlock()
+	if srv != nil {
+		_ = srv.Close()
+	}
+	if ln != nil {
+		_ = ln.Close()
+	}
+}
+
+// urlFor returns the loopback URL for one camera resource, or "" when the
+// proxy is not running so the caller can fall back.
+func (p *streamProxy) urlFor(cameraID, file string) string {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	if p.ln == nil || p.token == "" || !safeCameraID(cameraID) {
+		return ""
+	}
+	return fmt.Sprintf("http://%s/s/%s/%s/%s",
+		p.ln.Addr().String(), p.token, cameraID, file)
+}
+
+func (p *streamProxy) handle(w http.ResponseWriter, r *http.Request) {
+	p.mu.RLock()
+	token, target, user, pass, client := p.token, p.target, p.user, p.pass, p.client
+	p.mu.RUnlock()
+	if token == "" || client == nil {
+		http.NotFound(w, r)
+		return
+	}
+
+	// /s/<token>/<camera>/<file>
+	parts := strings.Split(strings.TrimPrefix(r.URL.Path, "/"), "/")
+	if len(parts) != 4 || parts[0] != "s" {
+		http.NotFound(w, r)
+		return
+	}
+	// Constant time: the token is the only thing standing between another
+	// local process and a live view of customers' faces.
+	if subtle.ConstantTimeCompare([]byte(parts[1]), []byte(token)) != 1 {
+		// 404 rather than 403. There is nothing here to tell an unwelcome
+		// caller they have found the right door with the wrong key.
+		http.NotFound(w, r)
+		return
+	}
+	cameraID := parts[2]
+	if !safeCameraID(cameraID) {
+		http.NotFound(w, r)
+		return
+	}
+
+	// An allow-list, not a prefix match. Everything else the engine serves -
+	// the identity list, the gallery, erasure - stays unreachable through here
+	// even for a caller holding the token.
+	//
+	// frame.jpg is listed although no screen asks for one yet. It is reachable
+	// only through urlFor, which is internal, so it adds no bound API nobody
+	// calls; it is here so that adding a still later is a change to a screen
+	// rather than a change to the one file where a mistake is a credentialed
+	// proxy onto the biometric API.
+	var enginePath string
+	switch parts[3] {
+	case "stream.mjpeg":
+		enginePath = "/api/cameras/" + cameraID + "/stream.mjpeg"
+	case "frame.jpg":
+		enginePath = "/api/cameras/" + cameraID + "/frame.jpg"
+	default:
+		http.NotFound(w, r)
+		return
+	}
+
+	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, target+enginePath, nil)
+	if err != nil {
+		http.Error(w, "bad upstream request", http.StatusInternalServerError)
+		return
+	}
+	// frame.jpg takes width and quality; the engine re-encodes on demand.
+	req.URL.RawQuery = r.URL.RawQuery
+	if user != "" {
+		req.SetBasicAuth(user, pass)
+	}
+
+	resp, err := client.Do(req)
+	if err != nil {
+		http.Error(w, "engine unreachable", http.StatusBadGateway)
+		return
+	}
+	defer resp.Body.Close()
+
+	for _, h := range []string{"Content-Type", "Cache-Control", "Pragma", "Expires"} {
+		if v := resp.Header.Get(h); v != "" {
+			w.Header().Set(h, v)
+		}
+	}
+	w.WriteHeader(resp.StatusCode)
+
+	// Copied by hand rather than with io.Copy so every chunk is flushed. An
+	// MJPEG stream never ends, so anything buffered waiting for a full buffer
+	// is a tile that stays blank forever - which is the same symptom as the
+	// bug this file exists to fix, and would look like it had not worked.
+	flusher, _ := w.(http.Flusher)
+	buf := make([]byte, 32*1024)
+	for {
+		n, rerr := resp.Body.Read(buf)
+		if n > 0 {
+			if _, werr := w.Write(buf[:n]); werr != nil {
+				return // webview went away
+			}
+			if flusher != nil {
+				flusher.Flush()
+			}
+		}
+		if rerr != nil {
+			return
+		}
+	}
+}

desktop/stream_proxy_test.go

@@ -0,0 +1,296 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"strings"
+	"testing"
+	"time"
+)
+
+// fakeEngine stands in for the Python engine: it demands Basic auth exactly as
+// the real one does when a credential is configured, and records what it was
+// asked for.
+type fakeEngine struct {
+	*httptest.Server
+	gotPath string
+	gotUser string
+	gotPass string
+	hadAuth bool
+}
+
+func newFakeEngine(t *testing.T, body string) *fakeEngine {
+	t.Helper()
+	f := &fakeEngine{}
+	f.Server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		f.gotPath = r.URL.Path
+		if r.URL.RawQuery != "" {
+			f.gotPath += "?" + r.URL.RawQuery
+		}
+		f.gotUser, f.gotPass, f.hadAuth = r.BasicAuth()
+		if !f.hadAuth {
+			w.Header().Set("WWW-Authenticate", `Basic realm="behavision"`)
+			w.WriteHeader(http.StatusUnauthorized)
+			return
+		}
+		w.Header().Set("Content-Type", "multipart/x-mixed-replace; boundary=frame")
+		_, _ = io.WriteString(w, body)
+	}))
+	t.Cleanup(f.Close)
+	return f
+}
+
+func startProxy(t *testing.T, engine string, user, pass string) *streamProxy {
+	t.Helper()
+	p := newStreamProxy()
+	if err := p.start(engine, user, pass); err != nil {
+		t.Fatalf("start: %v", err)
+	}
+	t.Cleanup(p.stop)
+	return p
+}
+
+func get(t *testing.T, url string) (int, string) {
+	t.Helper()
+	c := &http.Client{Timeout: 5 * time.Second}
+	resp, err := c.Get(url)
+	if err != nil {
+		t.Fatalf("get %s: %v", url, err)
+	}
+	defer resp.Body.Close()
+	b, _ := io.ReadAll(resp.Body)
+	return resp.StatusCode, string(b)
+}
+
+// The whole point: the webview gets a URL it can actually load, and the
+// password stays behind. A credential in the src is both unloadable in a
+// Chromium webview and readable by anything that can see the DOM.
+func TestTheCameraURLCarriesNoPassword(t *testing.T) {
+	engine := newFakeEngine(t, "frames")
+	p := startProxy(t, engine.URL, "behavision", "hunter2-the-real-one")
+
+	u := p.urlFor("cam2", "stream.mjpeg")
+	if u == "" {
+		t.Fatal("no url while the proxy is running")
+	}
+	if strings.Contains(u, "hunter2-the-real-one") || strings.Contains(u, "behavision:") {
+		t.Fatalf("credential leaked into the tile URL: %s", u)
+	}
+	if !strings.HasPrefix(u, "http://127.0.0.1:") {
+		t.Fatalf("relay must be loopback only, got %s", u)
+	}
+}
+
+func TestTheRelayAttachesTheCredentialItself(t *testing.T) {
+	engine := newFakeEngine(t, "frame-bytes")
+	p := startProxy(t, engine.URL, "behavision", "s3cret")
+
+	code, body := get(t, p.urlFor("cam2", "stream.mjpeg"))
+	if code != http.StatusOK {
+		t.Fatalf("want 200 through the relay, got %d", code)
+	}
+	if body != "frame-bytes" {
+		t.Fatalf("body not relayed unchanged: %q", body)
+	}
+	if !engine.hadAuth || engine.gotUser != "behavision" || engine.gotPass != "s3cret" {
+		t.Fatalf("engine did not receive the credential: auth=%v user=%q",
+			engine.hadAuth, engine.gotUser)
+	}
+	if engine.gotPath != "/api/cameras/cam2/stream.mjpeg" {
+		t.Fatalf("wrong upstream path: %s", engine.gotPath)
+	}
+}
+
+// The token is what keeps every other process on a shop PC from opening a live
+// view of customers' faces, now that the relay itself has no password.
+func TestAnotherProcessCannotGuessItsWayIn(t *testing.T) {
+	engine := newFakeEngine(t, "frames")
+	p := startProxy(t, engine.URL, "behavision", "s3cret")
+	addr := p.ln.Addr().String()
+
+	for _, bad := range []string{"", "0", strings.Repeat("a", 64), "wrong-token"} {
+		url := fmt.Sprintf("http://%s/s/%s/cam2/stream.mjpeg", addr, bad)
+		if code, _ := get(t, url); code != http.StatusNotFound {
+			t.Fatalf("token %q got %d, want 404", bad, code)
+		}
+	}
+	if engine.hadAuth {
+		t.Fatal("a rejected request still reached the engine")
+	}
+}
+
+// A camera id is interpolated into the upstream path, so it has to be a camera
+// id and not a way to walk to a different endpoint with the credential
+// attached.
+func TestACameraIdCannotClimbOutOfItsPath(t *testing.T) {
+	engine := newFakeEngine(t, "frames")
+	p := startProxy(t, engine.URL, "behavision", "s3cret")
+	addr := p.ln.Addr().String()
+
+	for _, bad := range []string{"..", "%2e%2e", "cam2/../../api/identities", "cam 2", ""} {
+		url := fmt.Sprintf("http://%s/s/%s/%s/stream.mjpeg", addr, p.token, bad)
+		code, _ := get(t, url)
+		if code != http.StatusNotFound {
+			t.Fatalf("camera id %q got %d, want 404", bad, code)
+		}
+	}
+	if strings.Contains(engine.gotPath, "identities") {
+		t.Fatalf("reached a non-camera endpoint: %s", engine.gotPath)
+	}
+}
+
+// Only the two files a tile needs. The engine also serves the identity list and
+// the erasure endpoint; holding the token must not open those.
+func TestOnlyTheTwoCameraFilesAreReachable(t *testing.T) {
+	engine := newFakeEngine(t, "frames")
+	p := startProxy(t, engine.URL, "behavision", "s3cret")
+	addr := p.ln.Addr().String()
+
+	for _, bad := range []string{"identities", "stats", "commission", "stream.mjpeg.bak"} {
+		url := fmt.Sprintf("http://%s/s/%s/cam2/%s", addr, p.token, bad)
+		if code, _ := get(t, url); code != http.StatusNotFound {
+			t.Fatalf("file %q got %d, want 404", bad, code)
+		}
+	}
+
+	for _, good := range []string{"stream.mjpeg", "frame.jpg"} {
+		url := fmt.Sprintf("http://%s/s/%s/cam2/%s", addr, p.token, good)
+		if code, _ := get(t, url); code != http.StatusOK {
+			t.Fatalf("file %q got %d, want 200", good, code)
+		}
+	}
+}
+
+// frame.jpg takes width and quality - the engine re-encodes on demand, and a
+// relay that dropped the query would silently serve full-size frames.
+func TestTheQueryStringSurvivesTheRelay(t *testing.T) {
+	engine := newFakeEngine(t, "frames")
+	p := startProxy(t, engine.URL, "behavision", "s3cret")
+
+	url := p.urlFor("cam2", "frame.jpg") + "?width=640&quality=70"
+	if code, _ := get(t, url); code != http.StatusOK {
+		t.Fatalf("got %d", code)
+	}
+	if !strings.Contains(engine.gotPath, "width=640") ||
+		!strings.Contains(engine.gotPath, "quality=70") {
+		t.Fatalf("query dropped: %s", engine.gotPath)
+	}
+}
+
+// An engine that is not running must read as a bad gateway, not as a hang. A
+// blank tile that never resolves is the symptom this whole file exists to end.
+func TestAnEngineThatIsDownFailsQuickly(t *testing.T) {
+	// Port 1 on loopback: nothing listens, and the connection is refused
+	// rather than dropped, so this is fast and deterministic.
+	p := startProxy(t, "http://127.0.0.1:1", "behavision", "s3cret")
+
+	done := make(chan int, 1)
+	go func() { code, _ := get(t, p.urlFor("cam2", "stream.mjpeg")); done <- code }()
+	select {
+	case code := <-done:
+		if code != http.StatusBadGateway {
+			t.Fatalf("want 502, got %d", code)
+		}
+	case <-time.After(8 * time.Second):
+		t.Fatal("a dead engine left the request hanging")
+	}
+}
+
+// Stopping must actually free the port, or a restarted engine leaves listeners
+// behind for the life of the process.
+func TestStoppingReleasesEverything(t *testing.T) {
+	engine := newFakeEngine(t, "frames")
+	p := newStreamProxy()
+	if err := p.start(engine.URL, "u", "p"); err != nil {
+		t.Fatalf("start: %v", err)
+	}
+	url := p.urlFor("cam2", "stream.mjpeg")
+	if code, _ := get(t, url); code != http.StatusOK {
+		t.Fatalf("want 200 before stop, got %d", code)
+	}
+
+	p.stop()
+
+	if got := p.urlFor("cam2", "stream.mjpeg"); got != "" {
+		t.Fatalf("still handing out URLs after stop: %s", got)
+	}
+	c := &http.Client{Timeout: 3 * time.Second}
+	if resp, err := c.Get(url); err == nil {
+		resp.Body.Close()
+		t.Fatal("listener still accepting after stop")
+	}
+}
+
+// start twice must not leave two listeners, which is what a restarted engine
+// would otherwise cause.
+func TestStartingTwiceIsANoOp(t *testing.T) {
+	engine := newFakeEngine(t, "frames")
+	p := startProxy(t, engine.URL, "u", "p")
+
+	first := p.urlFor("cam2", "stream.mjpeg")
+	if err := p.start(engine.URL, "u", "p"); err != nil {
+		t.Fatalf("second start: %v", err)
+	}
+	if second := p.urlFor("cam2", "stream.mjpeg"); second != first {
+		t.Fatalf("second start moved the relay: %s -> %s", first, second)
+	}
+}
+
+// Against the real engine, which the unit tests above deliberately do not
+// touch. Skipped unless TEST_ENGINE_URL is set, the same rule the server's
+// live store tests follow: the suite must stay runnable with no services.
+//
+//	TEST_ENGINE_URL=http://127.0.0.1:8010 \
+//	TEST_ENGINE_USER=... TEST_ENGINE_PASS=... go test ./desktop/ -run Live
+//
+// It exists because everything above proves the relay against a fake that
+// agrees with me. Only a real engine proves the thing that was actually
+// broken: that a multipart MJPEG stream arrives through the relay in pieces,
+// rather than being buffered into a tile that never paints.
+func TestLiveRelayCarriesRealMJPEGFrames(t *testing.T) {
+	base := os.Getenv("TEST_ENGINE_URL")
+	if base == "" {
+		t.Skip("set TEST_ENGINE_URL to run the live relay test")
+	}
+	cam := os.Getenv("TEST_ENGINE_CAMERA")
+	if cam == "" {
+		cam = "cam2"
+	}
+	p := startProxy(t, base, os.Getenv("TEST_ENGINE_USER"), os.Getenv("TEST_ENGINE_PASS"))
+
+	url := p.urlFor(cam, "stream.mjpeg")
+	req, _ := http.NewRequest(http.MethodGet, url, nil)
+	resp, err := (&http.Client{}).Do(req)
+	if err != nil {
+		t.Fatalf("relay: %v", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("relay returned %d - the credential did not reach the engine", resp.StatusCode)
+	}
+	if ct := resp.Header.Get("Content-Type"); !strings.Contains(ct, "multipart") {
+		t.Fatalf("not a stream: Content-Type %q", ct)
+	}
+
+	// Read until two JPEG start markers have gone past. One proves it opened;
+	// two prove it is still delivering, which is the difference between a
+	// working tile and a single frozen frame.
+	deadline := time.Now().Add(15 * time.Second)
+	var seen, total int
+	buf := make([]byte, 16*1024)
+	for seen < 2 && time.Now().Before(deadline) {
+		n, rerr := resp.Body.Read(buf)
+		total += n
+		seen += strings.Count(string(buf[:n]), "\xff\xd8\xff")
+		if rerr != nil {
+			break
+		}
+	}
+	if seen < 2 {
+		t.Fatalf("only %d JPEG frames in %d bytes - the relay is not streaming", seen, total)
+	}
+	t.Logf("relayed %d frames in %d bytes with no credential in the URL", seen, total)
+}

desktop/tray.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"os"
 	"sync"
 	"time"
 
@@ -10,6 +11,25 @@ import (
 	"github.com/wailsapp/wails/v2/pkg/runtime"
 )
 
+// BEHAVISION_NO_TRAY runs the window with no tray icon.
+//
+// It exists so the UI can be looked at on a Mac. fyne.io/systray's nativeLoop
+// must own the main thread on macOS - a Cocoa requirement, not a library
+// choice - and Wails already holds it, so starting both kills the process with
+// a SIGTRAP inside cgo before a single screen is drawn. On Windows, which is
+// what ships, a tray on its own goroutine is fine. That asymmetry is why this
+// went unnoticed for so long: the shop-floor UI had never once been run on the
+// platform it is developed on, so every screen in it was unreviewed.
+//
+// Deliberately an environment variable and NOT a GOOS check. A build that
+// quietly drops the tray on some platform is how a shop PC ends up with no
+// control surface at all - the one thing a shop manager has - and it would
+// fail exactly where nobody is watching. Nothing is skipped unless a person
+// asked for it, by name, on this run.
+const noTrayEnv = "BEHAVISION_NO_TRAY"
+
+func trayDisabled() bool { return os.Getenv(noTrayEnv) != "" }
+
 // tray is the always-present control surface. Wails v2 has no systray of its
 // own, so this drives fyne.io/systray alongside the window.
 //
@@ -32,6 +52,9 @@ type tray struct {
 func newTray(a *App) *tray { return &tray{app: a, quit: make(chan struct{})} }
 
 func (t *tray) start(ctx context.Context) {
+	if trayDisabled() {
+		return
+	}
 	t.once.Do(func() {
 		go systray.Run(func() { t.onReady(ctx) }, func() {})
 	})
@@ -43,6 +66,13 @@ func (t *tray) stop() {
 	default:
 		close(t.quit)
 	}
+	// systray.Quit() on a systray that was never started is not a no-op in
+	// v1.12.2, so the guard has to be on both ends or quitting the window
+	// takes the process down with it - a crash on exit, which is the failure
+	// most likely to be shrugged off as "it closed, fine".
+	if trayDisabled() {
+		return
+	}
 	systray.Quit()
 }
 

server/internal/store/api_arrivals_live_test.go

@@ -39,6 +39,38 @@ func liveStore(t *testing.T) *Store {
 	return st
 }
 
+// dropTenant removes a seeded tenant when the test that made it finishes.
+//
+// Without this these tests are a slow leak. Every one of them seeds its own
+// tenant - deliberately, so they can run in any order and so the isolation
+// assertions have a real neighbour - and none of them ever removed it. A dev
+// database reached 242 abandoned tenants against the single real one, which is
+// not merely untidy: the platform admin's Companies screen lists every client,
+// so the one real company was buried under pages of `walk1788761685056287000`.
+//
+// Registered against the CLIENT rather than each table because every foreign
+// key onto clients is ON DELETE CASCADE, so one delete takes the sites,
+// visitors, visits, face images, embeddings, cameras and agents with it. A
+// per-table list would rot the first time a migration adds a table, and it
+// would rot silently - which is the shape of the bug it is cleaning up after.
+//
+// t.Cleanup runs LIFO and liveStore registers st.Close before any seeding, so
+// the delete still has a live pool when it runs.
+func dropTenant(t *testing.T, st *Store, clientID string) {
+	t.Helper()
+	t.Cleanup(func() {
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+		if _, err := st.pool.Exec(ctx,
+			`DELETE FROM clients WHERE id = $1::uuid`, clientID); err != nil {
+			// Reported rather than ignored: a tenant left behind is the very
+			// thing this exists to prevent, and swallowing the error would let
+			// the leak return with nothing to show for it.
+			t.Errorf("cleanup tenant %s: %v", clientID, err)
+		}
+	})
+}
+
 // seedTenant builds a client, a site and n visits, and returns the client id.
 // Every test gets its own tenant so they can run in any order without a
 // truncate between them - and so the isolation assertions below have a real
@@ -52,6 +84,7 @@ func seedTenant(t *testing.T, st *Store, name string, n int, withImages bool) (c
 	if err != nil {
 		t.Fatalf("seed client: %v", err)
 	}
+	dropTenant(t, st, clientID)
 	err = st.pool.QueryRow(ctx, `
 		INSERT INTO sites (client_id, name, slug) VALUES ($1::uuid, $2, $3)
 		RETURNING id::text`, clientID, name+" Main", name+"-main").Scan(&siteID)

server/internal/store/api_faces_live_test.go

@@ -26,6 +26,7 @@ func seedAgentSite(t *testing.T, st *Store, name string) ingest.Site {
 		name).Scan(&site.ClientID); err != nil {
 		t.Fatalf("seed client: %v", err)
 	}
+	dropTenant(t, st, site.ClientID)
 	if err := st.pool.QueryRow(ctx, `
 		INSERT INTO sites (client_id, name, slug) VALUES ($1::uuid, $2, $3)
 		RETURNING id::text`, site.ClientID, name, name).Scan(&site.SiteID); err != nil {