Add options to configure ActionCable backend

This is to support running the ActionCable server in a separate
process from the web server

internal/config/config.go

@@ -43,10 +43,12 @@ type RedisConfig struct {
 type Config struct {
 	Redis                    *RedisConfig  `toml:"redis"`
 	Backend                  *url.URL      `toml:"-"`
+	CableBackend             *url.URL      `toml:"-"`
 	Version                  string        `toml:"-"`
 	DocumentRoot             string        `toml:"-"`
 	DevelopmentMode          bool          `toml:"-"`
 	Socket                   string        `toml:"-"`
+	CableSocket              string        `toml:"-"`
 	ProxyHeadersTimeout      time.Duration `toml:"-"`
 	APILimit                 uint          `toml:"-"`
 	APIQueueLimit            uint          `toml:"-"`

internal/upstream/routes.go

@@ -162,7 +162,7 @@ func (u *upstream) configureRoutes() {
 
 	static := &staticpages.Static{DocumentRoot: u.DocumentRoot}
 	proxy := buildProxy(u.Backend, u.Version, u.RoundTripper)
-	simpleProxy := proxypkg.NewProxy(u.Backend, u.Version, u.RoundTripper)
+	cableProxy := proxypkg.NewProxy(u.CableBackend, u.Version, u.CableRoundTripper)
 
 	signingTripper := secret.NewRoundTripper(u.RoundTripper, u.Version)
 	signingProxy := buildProxy(u.Backend, u.Version, signingTripper)
@@ -193,7 +193,7 @@ func (u *upstream) configureRoutes() {
 		route("POST", ciAPIPattern+`v1/builds/[0-9]+/artifacts\z`, contentEncodingHandler(artifacts.UploadArtifacts(api, signingProxy))),
 
 		// ActionCable websocket
-		wsRoute(`^/-/cable\z`, simpleProxy),
+		wsRoute(`^/-/cable\z`, cableProxy),
 
 		// Terminal websocket
 		wsRoute(projectPattern+`-/environments/[0-9]+/terminal.ws\z`, channel.Handler(api)),

internal/upstream/upstream.go

@@ -32,9 +32,10 @@ var (
 
 type upstream struct {
 	config.Config
-	URLPrefix    urlprefix.Prefix
-	Routes       []routeEntry
-	RoundTripper http.RoundTripper
+	URLPrefix         urlprefix.Prefix
+	Routes            []routeEntry
+	RoundTripper      http.RoundTripper
+	CableRoundTripper http.RoundTripper
 }
 
 func NewUpstream(cfg config.Config, accessLogger *logrus.Logger) http.Handler {
@@ -44,7 +45,14 @@ func NewUpstream(cfg config.Config, accessLogger *logrus.Logger) http.Handler {
 	if up.Backend == nil {
 		up.Backend = DefaultBackend
 	}
+	if up.CableBackend == nil {
+		up.CableBackend = up.Backend
+	}
+	if up.CableSocket == "" {
+		up.CableSocket = up.Socket
+	}
 	up.RoundTripper = roundtripper.NewBackendRoundTripper(up.Backend, up.Socket, up.ProxyHeadersTimeout, cfg.DevelopmentMode)
+	up.CableRoundTripper = roundtripper.NewBackendRoundTripper(up.CableBackend, up.CableSocket, up.ProxyHeadersTimeout, cfg.DevelopmentMode)
 	up.configureURLPrefix()
 	up.configureRoutes()
 

main.go

@@ -46,6 +46,8 @@ var listenNetwork = flag.String("listenNetwork", "tcp", "Listen 'network' (tcp,
 var listenUmask = flag.Int("listenUmask", 0, "Umask for Unix socket")
 var authBackend = flag.String("authBackend", upstream.DefaultBackend.String(), "Authentication/authorization backend")
 var authSocket = flag.String("authSocket", "", "Optional: Unix domain socket to dial authBackend at")
+var cableBackend = flag.String("cableBackend", upstream.DefaultBackend.String(), "ActionCable backend")
+var cableSocket = flag.String("cableSocket", "", "Optional: Unix domain socket to dial cableBackend at")
 var pprofListenAddr = flag.String("pprofListenAddr", "", "pprof listening address, e.g. 'localhost:6060'")
 var documentRoot = flag.String("documentRoot", "public", "Path to static files content")
 var proxyHeadersTimeout = flag.Duration("proxyHeadersTimeout", 5*time.Minute, "How long to wait for response headers when proxying the request")
@@ -91,6 +93,11 @@ func main() {
 		log.WithError(err).Fatal("Invalid authBackend")
 	}
 
+	cableBackendURL, err := parseAuthBackend(*cableBackend)
+	if err != nil {
+		log.WithError(err).Fatal("Invalid cableBackend")
+	}
+
 	log.WithField("version", Version).WithField("build_time", BuildTime).Print("Starting")
 
 	// Good housekeeping for Unix sockets: unlink before binding
@@ -137,7 +144,9 @@ func main() {
 	secret.SetPath(*secretPath)
 	cfg := config.Config{
 		Backend:                  backendURL,
+		CableBackend:             cableBackendURL,
 		Socket:                   *authSocket,
+		CableSocket:              *cableSocket,
 		Version:                  Version,
 		DocumentRoot:             *documentRoot,
 		DevelopmentMode:          *developmentMode,