feat: configurable Access-Control-Allow-Origin (#406)

Dockerfile.controller

@@ -34,6 +34,7 @@ EXPOSE 8892
 
 ENV FTL_CONTROLLER_BIND="http://0.0.0.0:8899"
 ENV FTL_CONTROLLER_ADVERTISE="http://127.0.0.1:8899"
+ENV FTL_CONTROLLER_ALLOW_ORIGIN="*"
 ENV FTL_CONTROLLER_DSN="postgres://host.docker.internal/ftl?sslmode=disable&user=postgres&password=secret"
 
 CMD ["/root/ftl-controller"]

backend/controller/controller.go

@@ -45,20 +45,29 @@ import (
 
 type Config struct {
 	Bind                         *url.URL            `help:"Socket to bind to." default:"http://localhost:8892" env:"FTL_CONTROLLER_BIND"`
-	Advertise                    *url.URL            `help:"Endpoint the Controller should advertise (use --bind if omitted)." default:"" env:"FTL_CONTROLLER_ADVERTISE"`
+	Advertise                    *url.URL            `help:"Endpoint the Controller should advertise (must be unique across the cluster, defaults to --bind if omitted)." env:"FTL_CONTROLLER_ADVERTISE"`
+	AllowOrigin                  string              `help:"Allow CORS requests from this origin." default:"*" env:"FTL_CONTROLLER_ALLOW_ORIGIN"`
 	Key                          model.ControllerKey `help:"Controller key (auto)." placeholder:"C<ULID>" default:"C00000000000000000000000000"`
 	DSN                          string              `help:"DAL DSN." default:"postgres://localhost/ftl?sslmode=disable&user=postgres&password=secret" env:"FTL_CONTROLLER_DSN"`
 	RunnerTimeout                time.Duration       `help:"Runner heartbeat timeout." default:"10s"`
 	DeploymentReservationTimeout time.Duration       `help:"Deployment reservation timeout." default:"120s"`
 	ArtefactChunkSize            int                 `help:"Size of each chunk streamed to the client." default:"1048576"`
 }
 
+func (c *Config) SetDefaults() {
+	if c.Advertise == nil {
+		c.Advertise = c.Bind
+	}
+}
+
 // Start the Controller. Blocks until the context is cancelled.
 func Start(ctx context.Context, config Config) error {
+	config.SetDefaults()
+
 	logger := log.FromContext(ctx)
 	logger.Infof("Starting FTL controller")
 
-	c, err := console.Server(ctx)
+	c, err := console.Server(ctx, config.AllowOrigin)
 	if err != nil {
 		return errors.WithStack(err)
 	}
@@ -116,6 +125,7 @@ func New(ctx context.Context, db *dal.DAL, config Config) (*Service, error) {
 	if config.Key.ULID() == (ulid.ULID{}) {
 		key = model.NewControllerKey()
 	}
+	config.SetDefaults()
 	svc := &Service{
 		dal:                db,
 		key:                key,
@@ -124,9 +134,6 @@ func New(ctx context.Context, db *dal.DAL, config Config) (*Service, error) {
 		routes:             map[string][]dal.Route{},
 		config:             config,
 	}
-	if config.Advertise.String() == "" {
-		config.Advertise = config.Bind
-	}
 
 	go runWithRetries(ctx, time.Second*1, time.Second*2, svc.syncRoutes)
 	go runWithRetries(ctx, time.Second*3, time.Second*5, svc.heartbeatController)

cmd/ftl-controller/main.go

@@ -7,15 +7,15 @@ import (
 	"github.com/alecthomas/kong"
 
 	_ "github.com/TBD54566975/ftl/backend/common/automaxprocs" // Set GOMAXPROCS to match Linux container CPU quota.
-	log2 "github.com/TBD54566975/ftl/backend/common/log"
+	log "github.com/TBD54566975/ftl/backend/common/log"
 	"github.com/TBD54566975/ftl/backend/controller"
 )
 
 var version = "dev"
 
 var cli struct {
 	Version          kong.VersionFlag  `help:"Show version."`
-	LogConfig        log2.Config       `embed:"" prefix:"log-"`
+	LogConfig        log.Config        `embed:"" prefix:"log-"`
 	ControllerConfig controller.Config `embed:""`
 }
 
@@ -25,7 +25,7 @@ func main() {
 		kong.UsageOnError(),
 		kong.Vars{"version": version},
 	)
-	ctx := log2.ContextWithLogger(context.Background(), log2.Configure(os.Stderr, cli.LogConfig))
+	ctx := log.ContextWithLogger(context.Background(), log.Configure(os.Stderr, cli.LogConfig))
 	err := controller.Start(ctx, cli.ControllerConfig)
 	kctx.FatalIfErrorf(err)
 }

console/cors.go

@@ -0,0 +1,11 @@
+package console
+
+import (
+	"net/http"
+)
+
+func writeCORSHeaders(w http.ResponseWriter, allowOrigin string) {
+	w.Header().Set("Access-Control-Allow-Origin", allowOrigin)
+	w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
+	w.Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
+}

console/local.go

@@ -17,7 +17,7 @@ import (
 var consoleURL, _ = url.Parse("http://localhost:5173")
 var proxy = httputil.NewSingleHostReverseProxy(consoleURL)
 
-func Server(ctx context.Context) (http.Handler, error) {
+func Server(ctx context.Context, allowOrigin string) (http.Handler, error) {
 	logger := log.FromContext(ctx)
 	logger.Infof("Building console...")
 
@@ -32,17 +32,16 @@ func Server(ctx context.Context) (http.Handler, error) {
 	}
 	logger.Infof("Console started")
 
-	return http.HandlerFunc(handler), nil
+	return http.HandlerFunc(handler(allowOrigin)), nil
 }
 
-func handler(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Access-Control-Allow-Origin", "*")
-	w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
-	w.Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
-
-	if r.Method == http.MethodOptions {
-		w.WriteHeader(http.StatusOK)
-		return
+func handler(allowOrigin string) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		writeCORSHeaders(w, allowOrigin)
+		if r.Method == http.MethodOptions {
+			w.WriteHeader(http.StatusOK)
+			return
+		}
+		proxy.ServeHTTP(w, r)
 	}
-	proxy.ServeHTTP(w, r)
 }

console/release.go

@@ -18,12 +18,13 @@ import (
 //go:embed all:client/dist
 var build embed.FS
 
-func Server(ctx context.Context) (http.Handler, error) {
+func Server(ctx context.Context, allowOrigin string) (http.Handler, error) {
 	dir, err := fs.Sub(build, "client/dist")
 	if err != nil {
 		return nil, errors.WithStack(err)
 	}
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		writeCORSHeaders(w, allowOrigin)
 		var f fs.File
 		var err error
 		filePath := strings.TrimPrefix(r.URL.Path, "/")