pomerium-cli: add support for a custom browser command (#2617)

internal/authclient/authclient.go

@@ -9,14 +9,12 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"os"
 	"time"
 
-	"github.com/skratchdot/open-golang/open"
 	"golang.org/x/sync/errgroup"
 )
 
-var openBrowser = open.Run
-
 // An AuthClient retrieves an authentication JWT via the Pomerium login API.
 type AuthClient struct {
 	cfg *config
@@ -141,5 +139,11 @@ func (client *AuthClient) runOpenBrowser(ctx context.Context, li net.Listener, s
 		return fmt.Errorf("failed to read login url: %w", err)
 	}
 
-	return openBrowser(string(bs))
+	err = client.cfg.open(string(bs))
+	if err != nil {
+		return fmt.Errorf("failed to open browser url: %w", err)
+	}
+
+	_, _ = fmt.Fprintf(os.Stderr, "Your browser has been opened to visit:\n\n%s\n\n", string(bs))
+	return nil
 }

internal/authclient/authclient_test.go

@@ -36,11 +36,8 @@ func TestAuthClient(t *testing.T) {
 		_ = srv.Serve(li)
 	}()
 
-	origOpenBrowser := openBrowser
-	defer func() {
-		openBrowser = origOpenBrowser
-	}()
-	openBrowser = func(input string) error {
+	ac := New()
+	ac.cfg.open = func(input string) error {
 		u, err := url.Parse(input)
 		if err != nil {
 			return err
@@ -64,7 +61,6 @@ func TestAuthClient(t *testing.T) {
 		return nil
 	}
 
-	ac := New()
 	rawJWT, err := ac.GetJWT(ctx, &url.URL{
 		Scheme: "http",
 		Host:   li.Addr().String(),

internal/authclient/config.go

@@ -2,14 +2,18 @@ package authclient
 
 import (
 	"crypto/tls"
+
+	"github.com/skratchdot/open-golang/open"
 )
 
 type config struct {
+	open      func(rawURL string) error
 	tlsConfig *tls.Config
 }
 
 func getConfig(options ...Option) *config {
 	cfg := new(config)
+	WithBrowserCommand("")(cfg)
 	for _, o := range options {
 		o(cfg)
 	}
@@ -19,6 +23,19 @@ func getConfig(options ...Option) *config {
 // An Option modifies the config.
 type Option func(*config)
 
+// WithBrowserCommand returns an option to configure the browser command.
+func WithBrowserCommand(browserCommand string) Option {
+	return func(cfg *config) {
+		if browserCommand == "" {
+			cfg.open = open.Run
+		} else {
+			cfg.open = func(rawURL string) error {
+				return open.RunWith(rawURL, browserCommand)
+			}
+		}
+	}
+}
+
 // WithTLSConfig returns an option to configure the tls config.
 func WithTLSConfig(tlsConfig *tls.Config) Option {
 	return func(cfg *config) {