feat: add external-auth cli (#10052)

* feat: add `external-auth` cli

* Add subcommands

* Improve descriptions

* Add external-auth subcommand

* Fix docs

* Fix gen

* Fix comment

* Fix golden file

cli/externalauth_test.go

@@ -0,0 +1,49 @@
+package cli_test
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/coder/coder/v2/cli/clitest"
+	"github.com/coder/coder/v2/cli/cliui"
+	"github.com/coder/coder/v2/coderd/httpapi"
+	"github.com/coder/coder/v2/codersdk/agentsdk"
+	"github.com/coder/coder/v2/pty/ptytest"
+)
+
+func TestExternalAuth(t *testing.T) {
+	t.Parallel()
+	t.Run("CanceledWithURL", func(t *testing.T) {
+		t.Parallel()
+		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			httpapi.Write(context.Background(), w, http.StatusOK, agentsdk.ExternalAuthResponse{
+				URL: "https://github.com",
+			})
+		}))
+		t.Cleanup(srv.Close)
+		url := srv.URL
+		inv, _ := clitest.New(t, "--agent-url", url, "external-auth", "access-token", "github")
+		pty := ptytest.New(t)
+		inv.Stdout = pty.Output()
+		waiter := clitest.StartWithWaiter(t, inv)
+		pty.ExpectMatch("https://github.com")
+		waiter.RequireIs(cliui.Canceled)
+	})
+	t.Run("SuccessWithToken", func(t *testing.T) {
+		t.Parallel()
+		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			httpapi.Write(context.Background(), w, http.StatusOK, agentsdk.ExternalAuthResponse{
+				AccessToken: "bananas",
+			})
+		}))
+		t.Cleanup(srv.Close)
+		url := srv.URL
+		inv, _ := clitest.New(t, "--agent-url", url, "external-auth", "access-token", "github")
+		pty := ptytest.New(t)
+		inv.Stdout = pty.Output()
+		clitest.Start(t, inv)
+		pty.ExpectMatch("bananas")
+	})
+}