GitHub Enterprise support (#658)

* Add option to specify custom GitHub instance

* Use correct GHE API endpoint URLs

Co-authored-by: Markus Wolf <knister.peter@shadowrun-clan.de>

* Extract slug from GitHub Enterprise URLs

Co-authored-by: Markus Wolf <knister.peter@shadowrun-clan.de>

* Use GITHUB_TOKEN for clone authenticate if provided

This change will allow use authentication for cloning actions
from private repositories or github enterprise instances.

Co-Authored-By: Markus Wolf <knister.peter@shadowrun-clan.de>

* Add section about using act on GitHub Enterprise to README

Co-authored-by: Markus Wolf <knister.peter@shadowrun-clan.de>

* Set GitHubInstance in runnerConfig in runner_test

Co-authored-by: Markus Wolf <knister.peter@shadowrun-clan.de>

Co-authored-by: hackercat <me@hackerc.at>
Co-authored-by: Markus Wolf <knister.peter@shadowrun-clan.de>

pkg/runner/run_context.go

@@ -503,7 +503,7 @@ func (rc *RunContext) getGithubContext() *githubContext {
 	}
 
 	repoPath := rc.Config.Workdir
-	repo, err := common.FindGithubRepo(repoPath)
+	repo, err := common.FindGithubRepo(repoPath, rc.Config.GitHubInstance)
 	if err != nil {
 		log.Warningf("unable to get git repo: %v", err)
 	} else {
@@ -644,6 +644,11 @@ func (rc *RunContext) withGithubEnv(env map[string]string) map[string]string {
 	env["GITHUB_SERVER_URL"] = "https://github.com"
 	env["GITHUB_API_URL"] = "https://api.github.com"
 	env["GITHUB_GRAPHQL_URL"] = "https://api.github.com/graphql"
+	if rc.Config.GitHubInstance != "github.com" {
+		env["GITHUB_SERVER_URL"] = fmt.Sprintf("https://%s", rc.Config.GitHubInstance)
+		env["GITHUB_API_URL"] = fmt.Sprintf("https://%s/api/v3", rc.Config.GitHubInstance)
+		env["GITHUB_GRAPHQL_URL"] = fmt.Sprintf("https://%s/api/graphql", rc.Config.GitHubInstance)
+	}
 
 	job := rc.Run.Job()
 	if job.RunsOn() != nil {

pkg/runner/runner.go

@@ -38,6 +38,7 @@ type Config struct {
 	UsernsMode            string            // user namespace to use
 	ContainerArchitecture string            // Desired OS/architecture platform for running containers
 	UseGitIgnore          bool              // controls if paths in .gitignore should not be copied into container, default true
+	GitHubInstance        string            // GitHub instance to use, default "github.com"
 }
 
 // Resolves the equivalent host path inside the container

pkg/runner/runner_test.go

@@ -56,6 +56,7 @@ func runTestJobFile(ctx context.Context, t *testing.T, tjfi TestJobFileInfo, sec
 			ReuseContainers:       false,
 			ContainerArchitecture: tjfi.containerArchitecture,
 			Secrets:               secrets,
+			GitHubInstance:        "github.com",
 		}
 
 		runner, err := New(runnerConfig)

pkg/runner/step_context.go

@@ -70,7 +70,11 @@ func (sc *StepContext) Executor() common.Executor {
 		if remoteAction == nil {
 			return common.NewErrorExecutor(formatError(step.Uses))
 		}
-		if remoteAction.IsCheckout() && rc.getGithubContext().isLocalCheckout(step) {
+
+		remoteAction.URL = rc.Config.GitHubInstance
+
+		github := rc.getGithubContext()
+		if remoteAction.IsCheckout() && github.isLocalCheckout(step) {
 			return func(ctx context.Context) error {
 				common.Logger(ctx).Debugf("Skipping actions/checkout")
 				return nil
@@ -80,9 +84,10 @@ func (sc *StepContext) Executor() common.Executor {
 		actionDir := fmt.Sprintf("%s/%s", rc.ActionCacheDir(), strings.ReplaceAll(step.Uses, "/", "-"))
 		return common.NewPipelineExecutor(
 			common.NewGitCloneExecutor(common.NewGitCloneExecutorInput{
-				URL: remoteAction.CloneURL(),
-				Ref: remoteAction.Ref,
-				Dir: actionDir,
+				URL:   remoteAction.CloneURL(),
+				Ref:   remoteAction.Ref,
+				Dir:   actionDir,
+				Token: github.Token,
 			}),
 			sc.setupAction(actionDir, remoteAction.Path),
 			sc.runAction(actionDir, remoteAction.Path),
@@ -568,6 +573,7 @@ func (sc *StepContext) runAction(actionDir string, actionPath string) common.Exe
 }
 
 type remoteAction struct {
+	URL  string
 	Org  string
 	Repo string
 	Path string
@@ -575,7 +581,7 @@ type remoteAction struct {
 }
 
 func (ra *remoteAction) CloneURL() string {
-	return fmt.Sprintf("https://github.com/%s/%s", ra.Org, ra.Repo)
+	return fmt.Sprintf("https://%s/%s/%s", ra.URL, ra.Org, ra.Repo)
 }
 
 func (ra *remoteAction) IsCheckout() bool {
@@ -601,6 +607,7 @@ func newRemoteAction(action string) *remoteAction {
 		Repo: matches[2],
 		Path: matches[4],
 		Ref:  matches[6],
+		URL:  "github.com",
 	}
 }