feat: run pre-entrypoint and post-entrypoint of docker actions (#1106)

A docker action can declare `runs.pre-entrypoint` and `runs.post-entrypoint` next to `runs.entrypoint` — the docker equivalent of a javascript action's `runs.pre`/`runs.post`. Neither key existed on `ActionRuns`, so the YAML decoder dropped them and docker actions silently skipped their setup and cleanup stages.

Only the entrypoint is stage specific. [`ContainerActionHandler`](https://github.com/actions/runner/blob/main/src/Runner.Worker/Handlers/ContainerActionHandler.cs) selects `Data.Pre`/`Data.Post` per stage but evaluates `runs.args` and `runs.env` unconditionally, so `docker create` receives the action's args and env on every stage. The `entrypoint` input stays main only, because it is read inside the main branch.

The stage is carried as the existing `stepStage` value rather than a separate parameter, and the pre and post stages reuse the action path resolution that `runPreStep`/`runPostStep` already open-coded three times, so the diff also drops those copies.

Known gap: `stepActionLocal.pre()` is a no-op for every `using`, so `pre-entrypoint` does not run for `uses: ./local-action` while `post-entrypoint` does. Closing it requires reading the action model before the main stage and adding a pre case to `getIfExpression` for `pre-if`, which also changes local node, go and composite actions — better as its own change.

---------

Co-authored-by: silverwind <2021+silverwind@noreply.gitea.com>
Co-authored-by: silverwind <me@silverwind.io>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1106
Reviewed-by: silverwind <2021+silverwind@noreply.gitea.com>
Co-authored-by: bircni <bircni@icloud.com>

act/model/action.go

@@ -84,7 +84,9 @@ type ActionRuns struct {
 	Post           string            `yaml:"post"`
 	PostIf         string            `yaml:"post-if"`
 	Image          string            `yaml:"image"`
+	PreEntrypoint  string            `yaml:"pre-entrypoint"`
 	Entrypoint     string            `yaml:"entrypoint"`
+	PostEntrypoint string            `yaml:"post-entrypoint"`
 	Args           []string          `yaml:"args"`
 	Steps          []Step            `yaml:"steps"`
 }

act/model/action_test.go

@@ -61,3 +61,22 @@ runs:
 		t.Fatalf("error = %q, want invalid value", err)
 	}
 }
+
+func TestReadActionDockerEntrypoints(t *testing.T) {
+	action, err := ReadAction(strings.NewReader(`
+runs:
+  using: docker
+  image: Dockerfile
+  pre-entrypoint: pre.sh
+  post-entrypoint: post.sh
+`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if action.Runs.PreEntrypoint != "pre.sh" {
+		t.Fatalf("pre-entrypoint = %q, want pre.sh", action.Runs.PreEntrypoint)
+	}
+	if action.Runs.PostEntrypoint != "post.sh" {
+		t.Fatalf("post-entrypoint = %q, want post.sh", action.Runs.PostEntrypoint)
+	}
+}

act/runner/action.go

@@ -207,7 +207,7 @@ func runActionImpl(step actionStep, actionDir string, remoteAction *remoteAction
 			if remoteAction == nil {
 				location = containerActionDir
 			}
-			return execAsDocker(ctx, step, actionName, actionDir, location, remoteAction == nil)
+			return execAsDocker(ctx, step, actionName, actionDir, location, remoteAction == nil, stepStageMain)
 		case x.IsComposite():
 			if err := maybeCopyToActionDir(ctx, step, actionDir, actionPath, containerActionDir); err != nil {
 				return err
@@ -305,7 +305,7 @@ func dockerActionImageTag(repository, actionName string, localAction bool) strin
 }
 
 // TODO: break out parts of function to reduce complexicity
-func execAsDocker(ctx context.Context, step actionStep, actionName, actionDir, basedir string, localAction bool) error {
+func execAsDocker(ctx context.Context, step actionStep, actionName, actionDir, basedir string, localAction bool, stage stepStage) error {
 	logger := common.Logger(ctx)
 	rc := step.getRunContext()
 	action := step.getActionModel()
@@ -386,17 +386,10 @@ func execAsDocker(ctx context.Context, step actionStep, actionName, actionDir, b
 		cmd = action.Runs.Args
 		evalDockerArgs(ctx, step, action, &cmd)
 	}
-	entrypoint := strings.Fields(eval.Interpolate(ctx, step.getStepModel().With["entrypoint"]))
+	entrypoint, err := dockerEntrypoint(ctx, step, eval, stage)
-	if len(entrypoint) == 0 {
-		if action.Runs.Entrypoint != "" {
-			entrypoint, err = shellquote.Split(action.Runs.Entrypoint)
 	if err != nil {
 		return err
 	}
-		} else {
-			entrypoint = nil
-		}
-	}
 	stepContainer := newStepContainer(ctx, step, image, cmd, entrypoint)
 	return common.NewPipelineExecutor(
 		prepImage,
@@ -409,6 +402,30 @@ func execAsDocker(ctx context.Context, step actionStep, actionName, actionDir, b
 	).Finally(stepContainer.Close())(ctx)
 }
 
+// dockerEntrypoint returns the entrypoint the action's image runs with for the given
+// stage. Only the main stage honours the `entrypoint` input.
+func dockerEntrypoint(ctx context.Context, step actionStep, eval ExpressionEvaluator, stage stepStage) ([]string, error) {
+	runs := step.getActionModel().Runs
+
+	var entrypoint string
+	switch stage {
+	case stepStagePre:
+		entrypoint = runs.PreEntrypoint
+	case stepStagePost:
+		entrypoint = runs.PostEntrypoint
+	default:
+		if fields := strings.Fields(eval.Interpolate(ctx, step.getStepModel().With["entrypoint"])); len(fields) > 0 {
+			return fields, nil
+		}
+		entrypoint = runs.Entrypoint
+	}
+
+	if entrypoint == "" {
+		return nil, nil
+	}
+	return shellquote.Split(entrypoint)
+}
+
 func evalDockerArgs(ctx context.Context, step step, action *model.Action, cmd *[]string) {
 	rc := step.getRunContext()
 	stepModel := step.getStepModel()
@@ -559,44 +576,57 @@ func hasPreStep(step actionStep) common.Conditional {
 		return action.Runs.Using.IsComposite() ||
 			(action.Runs.Using.IsNode() &&
 				action.Runs.Pre != "") ||
+			(action.Runs.Using.IsDocker() &&
+				action.Runs.PreEntrypoint != "") ||
 			(action.Runs.Using == model.ActionRunsUsingGo &&
 				action.Runs.Pre != "")
 	}
 }
 
+// actionStagePaths resolves where a step's action lives and where the job container sees
+// it, for the pre and post stage.
+func actionStagePaths(step actionStep) (actionDir, actionPath, actionName, containerActionDir string) {
+	rc := step.getRunContext()
+	stepModel := step.getStepModel()
+
+	if _, ok := step.(*stepActionRemote); ok {
+		actionDir = fmt.Sprintf("%s/%s", rc.ActionCacheDir(), stepModel.UsesHash())
+		actionPath = newRemoteAction(stepModel.Uses).Path
+	} else {
+		actionDir = filepath.Join(rc.Config.Workdir, stepModel.Uses)
+	}
+
+	actionName, containerActionDir = getContainerActionPaths(stepModel, path.Join(actionDir, actionPath), rc)
+	return actionDir, actionPath, actionName, containerActionDir
+}
+
+// execDockerActionStage runs a docker action's image for its pre or post stage.
+func execDockerActionStage(ctx context.Context, step actionStep, stage stepStage) error {
+	actionDir, actionPath, actionName, containerActionDir := actionStagePaths(step)
+
+	_, remote := step.(*stepActionRemote)
+	location := containerActionDir
+	if remote {
+		location = path.Join(actionDir, actionPath)
+	}
+	return execAsDocker(ctx, step, actionName, actionDir, location, !remote, stage)
+}
+
 func runPreStep(step actionStep) common.Executor {
 	return func(ctx context.Context) error {
 		logger := common.Logger(ctx)
 		logger.Debugf("run pre step for '%s'", step.getStepModel())
 
 		rc := step.getRunContext()
-		stepModel := step.getStepModel()
 		action := step.getActionModel()
 
+		actionDir, actionPath, _, containerActionDir := actionStagePaths(step)
+
 		x := action.Runs.Using
 		switch {
 		case x.IsNode():
 			// defaults in pre steps were missing, however provided inputs are available
 			populateEnvsFromInput(ctx, step.getEnv(), action, rc)
-			// todo: refactor into step
-			var actionDir string
-			var actionPath string
-			if _, ok := step.(*stepActionRemote); ok {
-				actionPath = newRemoteAction(stepModel.Uses).Path
-				actionDir = fmt.Sprintf("%s/%s", rc.ActionCacheDir(), stepModel.UsesHash())
-			} else {
-				actionDir = filepath.Join(rc.Config.Workdir, stepModel.Uses)
-				actionPath = ""
-			}
-
-			var actionLocation string
-			if actionPath != "" {
-				actionLocation = path.Join(actionDir, actionPath)
-			} else {
-				actionLocation = actionDir
-			}
-
-			_, containerActionDir := getContainerActionPaths(stepModel, actionLocation, rc)
 
 			if err := maybeCopyToActionDir(ctx, step, actionDir, actionPath, containerActionDir); err != nil {
 				return err
@@ -609,6 +639,12 @@ func runPreStep(step actionStep) common.Executor {
 
 			return rc.execJobContainer(containerArgs, *step.getEnv(), "", "")(ctx)
 
+		case x.IsDocker():
+			// defaults in pre steps were missing, however provided inputs are available
+			populateEnvsFromInput(ctx, step.getEnv(), action, rc)
+
+			return execDockerActionStage(ctx, step, stepStagePre)
+
 		case x.IsComposite():
 			if step.getCompositeSteps() == nil {
 				step.getCompositeRunContext(ctx)
@@ -622,25 +658,6 @@ func runPreStep(step actionStep) common.Executor {
 		case x == model.ActionRunsUsingGo:
 			// defaults in pre steps were missing, however provided inputs are available
 			populateEnvsFromInput(ctx, step.getEnv(), action, rc)
-			// todo: refactor into step
-			var actionDir string
-			var actionPath string
-			if _, ok := step.(*stepActionRemote); ok {
-				actionPath = newRemoteAction(stepModel.Uses).Path
-				actionDir = fmt.Sprintf("%s/%s", rc.ActionCacheDir(), stepModel.UsesHash())
-			} else {
-				actionDir = filepath.Join(rc.Config.Workdir, stepModel.Uses)
-				actionPath = ""
-			}
-
-			var actionLocation string
-			if actionPath != "" {
-				actionLocation = path.Join(actionDir, actionPath)
-			} else {
-				actionLocation = actionDir
-			}
-
-			_, containerActionDir := getContainerActionPaths(stepModel, actionLocation, rc)
 
 			if err := maybeCopyToActionDir(ctx, step, actionDir, actionPath, containerActionDir); err != nil {
 				return err
@@ -693,6 +710,8 @@ func hasPostStep(step actionStep) common.Conditional {
 		return action.Runs.Using.IsComposite() ||
 			(action.Runs.Using.IsNode() &&
 				action.Runs.Post != "") ||
+			(action.Runs.Using.IsDocker() &&
+				action.Runs.PostEntrypoint != "") ||
 			(action.Runs.Using == model.ActionRunsUsingGo &&
 				action.Runs.Post != "")
 	}
@@ -704,28 +723,9 @@ func runPostStep(step actionStep) common.Executor {
 		logger.Debugf("run post step for '%s'", step.getStepModel())
 
 		rc := step.getRunContext()
-		stepModel := step.getStepModel()
 		action := step.getActionModel()
 
-		// todo: refactor into step
+		actionDir, actionPath, _, containerActionDir := actionStagePaths(step)
-		var actionDir string
-		var actionPath string
-		if _, ok := step.(*stepActionRemote); ok {
-			actionPath = newRemoteAction(stepModel.Uses).Path
-			actionDir = fmt.Sprintf("%s/%s", rc.ActionCacheDir(), stepModel.UsesHash())
-		} else {
-			actionDir = filepath.Join(rc.Config.Workdir, stepModel.Uses)
-			actionPath = ""
-		}
-
-		var actionLocation string
-		if actionPath != "" {
-			actionLocation = path.Join(actionDir, actionPath)
-		} else {
-			actionLocation = actionDir
-		}
-
-		_, containerActionDir := getContainerActionPaths(stepModel, actionLocation, rc)
 
 		x := action.Runs.Using
 		switch {
@@ -740,6 +740,11 @@ func runPostStep(step actionStep) common.Executor {
 
 			return rc.execJobContainer(containerArgs, *step.getEnv(), "", "")(ctx)
 
+		case x.IsDocker():
+			populateEnvsFromSavedState(step.getEnv(), step, rc)
+
+			return execDockerActionStage(ctx, step, stepStagePost)
+
 		case x.IsComposite():
 			if err := maybeCopyToActionDir(ctx, step, actionDir, actionPath, containerActionDir); err != nil {
 				return err

act/runner/action_test.go

@@ -183,7 +183,7 @@ func TestExecAsDockerAutoRemove(t *testing.T) {
 		cm.On("Start", true).Return(func(context.Context) error { return nil })
 		cm.On("Close").Return(func(context.Context) error { return nil })
 
-		require.NoError(t, execAsDocker(context.Background(), step, "action", t.TempDir(), t.TempDir(), false))
+		require.NoError(t, execAsDocker(context.Background(), step, "action", t.TempDir(), t.TempDir(), false, stepStageMain))
 		cm.AssertExpectations(t)
 		assert.Equal(t, tc.removes, removes)
 	}
@@ -465,7 +465,7 @@ func TestExecAsDockerHoldsCloneLockForRemoteUncached(t *testing.T) {
 	defer cancel()
 
 	done := make(chan error, 1)
-	go func() { done <- execAsDocker(ctx, step, "test-action", actionDir, actionDir, false) }()
+	go func() { done <- execAsDocker(ctx, step, "test-action", actionDir, actionDir, false, stepStageMain) }()
 
 	select {
 	case <-innerEntered:
@@ -541,3 +541,86 @@ func TestDockerActionImageTag(t *testing.T) {
 		dockerActionImageTag("owner/repo", "./sub", true),
 	)
 }
+
+// Only the entrypoint is stage specific: every stage of a docker action receives runs.args
+// and runs.env, and the `entrypoint` input applies to the main stage alone.
+func TestExecAsDockerStageEntrypoint(t *testing.T) {
+	orig := ContainerNewContainer
+	defer func() { ContainerNewContainer = orig }()
+
+	for _, tc := range []struct {
+		name           string
+		stage          stepStage
+		wantEntrypoint []string
+	}{
+		{
+			name:           "main stage prefers the entrypoint input",
+			stage:          stepStageMain,
+			wantEntrypoint: []string{"input.sh"},
+		},
+		{
+			name:           "pre stage uses runs.pre-entrypoint",
+			stage:          stepStagePre,
+			wantEntrypoint: []string{"pre.sh", "--verbose"},
+		},
+		{
+			name:           "post stage uses runs.post-entrypoint",
+			stage:          stepStagePost,
+			wantEntrypoint: []string{"post.sh"},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			cm := &containerMock{}
+			var input *container.NewContainerInput
+			ContainerNewContainer = func(in *container.NewContainerInput) container.ExecutionsEnvironment {
+				input = in
+				return cm
+			}
+
+			step := &stepActionRemote{
+				Step: &model.Step{ID: "1", Uses: "org/action@v1", With: map[string]string{"entrypoint": "input.sh"}},
+				RunContext: &RunContext{
+					Config:       &Config{},
+					Run:          &model.Run{JobID: "1", Workflow: &model.Workflow{Jobs: map[string]*model.Job{"1": {}}}},
+					JobContainer: cm,
+				},
+				action: &model.Action{Runs: model.ActionRuns{
+					Using:          "docker",
+					Image:          "docker://node:14",
+					PreEntrypoint:  "pre.sh --verbose",
+					Entrypoint:     "main.sh",
+					PostEntrypoint: "post.sh",
+					Args:           []string{"hello"},
+					Env:            map[string]string{"MY_VAR": "world"},
+				}},
+				env: map[string]string{},
+			}
+
+			cm.On("Pull", false).Return(func(context.Context) error { return nil })
+			cm.On("Remove").Return(func(context.Context) error { return nil })
+			cm.On("Create", []string(nil), []string(nil)).Return(func(context.Context) error { return nil })
+			cm.On("Start", true).Return(func(context.Context) error { return nil })
+			cm.On("Close").Return(func(context.Context) error { return nil })
+
+			require.NoError(t, execAsDocker(context.Background(), step, "action", t.TempDir(), t.TempDir(), false, tc.stage))
+			require.NotNil(t, input)
+			assert.Equal(t, tc.wantEntrypoint, input.Entrypoint)
+			assert.Equal(t, []string{"hello"}, input.Cmd)
+			assert.Contains(t, input.Env, "MY_VAR=world")
+		})
+	}
+}
+
+func TestDockerActionHasPreAndPostStep(t *testing.T) {
+	newStep := func(runs model.ActionRuns) actionStep {
+		return &stepActionRemote{action: &model.Action{Runs: runs}}
+	}
+	ctx := context.Background()
+
+	assert.False(t, hasPreStep(newStep(model.ActionRuns{Using: "docker", Image: "Dockerfile"}))(ctx))
+	assert.False(t, hasPostStep(newStep(model.ActionRuns{Using: "docker", Image: "Dockerfile"}))(ctx))
+
+	withStages := model.ActionRuns{Using: "docker", Image: "Dockerfile", PreEntrypoint: "pre.sh", PostEntrypoint: "post.sh"}
+	assert.True(t, hasPreStep(newStep(withStages))(ctx))
+	assert.True(t, hasPostStep(newStep(withStages))(ctx))
+}

act/runner/expression.go

@@ -95,9 +95,7 @@ func (rc *RunContext) NewExpressionEvaluatorWithEnv(ctx context.Context, env map
 		Inputs:    inputs,
 		HashFiles: getHashFilesFunction(ctx, rc),
 	}
-	if rc.JobContainer != nil {
+	ee.Runner = rc.getRunnerContext(ctx)
-		ee.Runner = rc.JobContainer.GetRunnerContext(ctx)
-	}
 	return expressionEvaluator{
 		interpreter: exprparser.NewInterpeter(ee, exprparser.Config{
 			Run:        rc.Run,
@@ -149,9 +147,7 @@ func (rc *RunContext) NewStepExpressionEvaluator(ctx context.Context, step step)
 		Inputs:    inputs,
 		HashFiles: getHashFilesFunction(ctx, rc),
 	}
-	if rc.JobContainer != nil {
+	ee.Runner = rc.getRunnerContext(ctx)
-		ee.Runner = rc.JobContainer.GetRunnerContext(ctx)
-	}
 	return expressionEvaluator{
 		interpreter: exprparser.NewInterpeter(ee, exprparser.Config{
 			Run:        rc.Run,

act/runner/run_context.go

@@ -298,7 +298,7 @@ func (rc *RunContext) startHostEnvironment() common.Executor {
 			AllocatePTY: rc.Config.AllocatePTY,
 		}
 		rc.cleanUpJobContainer = rc.JobContainer.Remove()
-		for k, v := range rc.JobContainer.GetRunnerContext(ctx) {
+		for k, v := range rc.getRunnerContext(ctx) {
 			if v, ok := v.(string); ok {
 				rc.Env["RUNNER_"+strings.ToUpper(k)] = v
 			}
@@ -986,6 +986,21 @@ func (rc *RunContext) getStepsContext() map[string]*model.StepResult {
 	return rc.StepResults
 }
 
+// getRunnerContext returns the `runner` context: what the execution environment knows
+// (os, arch, temp, tool_cache) plus what only the runner process knows.
+func (rc *RunContext) getRunnerContext(ctx context.Context) map[string]any {
+	runnerContext := map[string]any{}
+	if rc.JobContainer != nil {
+		maps0.Copy(runnerContext, rc.JobContainer.GetRunnerContext(ctx))
+	}
+	runnerContext["name"] = rc.Config.RunnerName
+	runnerContext["environment"] = "self-hosted"
+	if rc.Config.RunnerDebug() {
+		runnerContext["debug"] = "1"
+	}
+	return runnerContext
+}
+
 func (rc *RunContext) getGithubContext(ctx context.Context) *model.GithubContext {
 	logger := common.Logger(ctx)
 	ghc := &model.GithubContext{
@@ -1170,7 +1185,7 @@ func nestedMapLookup(m map[string]any, ks ...string) (rval any) {
 	}
 }
 
-func (rc *RunContext) withGithubEnv(ctx context.Context, github *model.GithubContext, env map[string]string) map[string]string { //nolint:unparam // pre-existing issue from nektos/act
+func (rc *RunContext) withGithubEnv(ctx context.Context, github *model.GithubContext, env map[string]string) {
 	env["CI"] = "true"
 	env["GITHUB_WORKFLOW"] = github.Workflow
 	env["GITHUB_RUN_ID"] = github.RunID
@@ -1212,23 +1227,71 @@ func (rc *RunContext) withGithubEnv(ctx context.Context, github *model.GithubCon
 		env["GITHUB_RUN_ATTEMPT"] = github.RunAttempt
 	}
 
+	env["RUNNER_NAME"] = rc.Config.RunnerName
+	env["RUNNER_ENVIRONMENT"] = "self-hosted"
+	if workspace := parentDir(github.Workspace); workspace != "" {
+		env["RUNNER_WORKSPACE"] = workspace
+	}
+	if rc.Config.RunnerDebug() {
+		env["RUNNER_DEBUG"] = "1"
+	}
+
 	if rc.Config.ArtifactServerPath != "" {
 		setActionRuntimeVars(rc, env)
 	}
 
-	for _, platformName := range rc.runsOnPlatformNames(ctx) {
+	if imageOS := rc.imageOS(ctx); imageOS != "" {
-		if platformName != "" {
+		env["ImageOS"] = imageOS
-			if platformName == "ubuntu-latest" {
-				// hardcode current ubuntu-latest since we have no way to check that 'on the fly'
-				env["ImageOS"] = "ubuntu20"
-			} else {
-				platformName = strings.SplitN(strings.Replace(platformName, `-`, ``, 1), `.`, 2)[0]
-				env["ImageOS"] = platformName
 	}
+}
+
+// parentDir returns the directory containing p, or "" when p names no parent. Both
+// separators are accepted rather than filepath's, as p may describe a container while
+// the runner itself runs on Windows, or the other way round.
+func parentDir(p string) string {
+	if slash := strings.LastIndexAny(p, `/\`); slash > 0 {
+		return p[:slash]
 	}
+	return ""
+}
+
+// imageOS returns ImageOS, which setup-* actions use to tell one runner image release
+// from another. The resolved image tag is preferred over the runs-on label because it
+// still names a release when the label is a rolling one such as ubuntu-latest.
+func (rc *RunContext) imageOS(ctx context.Context) string {
+	if rc.Run.Job().RunsOn() == nil {
+		// A composite action runs on a synthetic job, and resolving its image would only
+		// log that runs-on is missing.
+		return ""
+	}
+	if imageOS := imageOSFromImage(rc.platformImage(ctx)); imageOS != "" {
+		return imageOS
 	}
 
-	return env
+	for _, platformName := range slices.Backward(rc.runsOnPlatformNames(ctx)) {
+		if platformName == "ubuntu-latest" {
+			// Rolling label whose image names no release either, so keep the historical value.
+			return "ubuntu20"
+		} else if platformName != "" {
+			return strings.SplitN(strings.Replace(platformName, `-`, ``, 1), `.`, 2)[0]
+		}
+	}
+	return ""
+}
+
+// imageOSTag matches an image reference tagged with an OS family ImageOS can report plus
+// its release, such as "docker.gitea.com/runner-images:ubuntu-24.04". Anything else
+// ("ubuntu-latest", "app:22.04", "catthehacker/ubuntu:act-22.04", or a registry port) is
+// left to the runs-on label rather than turned into a bogus OS.
+var imageOSTag = regexp.MustCompile(`:(ubuntu|win|macos)-?([0-9]+)[^/]*$`)
+
+// imageOSFromImage derives ImageOS from an image reference, e.g.
+// "docker.gitea.com/runner-images:ubuntu-24.04" yields "ubuntu24".
+func imageOSFromImage(image string) string {
+	if match := imageOSTag.FindStringSubmatch(image); match != nil {
+		return match[1] + match[2]
+	}
+	return ""
 }
 
 func setActionRuntimeVars(rc *RunContext, env map[string]string) {

act/runner/run_context_test.go

@@ -940,3 +940,117 @@ func TestRunContext_cleanupFailedStart(t *testing.T) {
 		assert.NotPanics(t, func() { (&RunContext{}).cleanupFailedStart(context.Background()) })
 	})
 }
+
+func TestImageOSFromImage(t *testing.T) {
+	for _, tc := range []struct {
+		image string
+		want  string
+	}{
+		{"", ""},
+		{"docker.gitea.com/runner-images:ubuntu-24.04", "ubuntu24"},
+		{"docker.gitea.com/runner-images:ubuntu-latest", ""},
+		{"runner-images:ubuntu22.04", "ubuntu22"},
+		{"node:20", ""},
+		{"ubuntu:22.04", ""},
+		{"ubuntu", ""},
+		{"catthehacker/ubuntu:act-22.04", ""},
+		{"myco/ubuntu:v2.1", ""},
+		{"myco/ubuntu:v22.04", ""},
+		{"app:release-1", ""},
+		{"app:1.2.3", ""},
+		{"app:build-2.1", ""},
+		{"registry.example.com:5000/runner-images", ""},
+		{"registry.example.com:5000/runner-images:ubuntu-24.04", "ubuntu24"},
+	} {
+		t.Run(tc.image, func(t *testing.T) {
+			assert.Equal(t, tc.want, imageOSFromImage(tc.image))
+		})
+	}
+}
+
+func createRunsOnRunContext(t *testing.T, runsOn string) *RunContext {
+	return createIfTestRunContext(map[string]*model.Job{
+		"job1": createJob(t, "runs-on: "+runsOn, ""),
+	})
+}
+
+func TestRunContextImageOS(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("prefers the release in the resolved image tag", func(t *testing.T) {
+		rc := createRunsOnRunContext(t, "ubuntu-latest")
+		rc.Config.Platforms = map[string]string{
+			"ubuntu-latest": "docker.gitea.com/runner-images:ubuntu-24.04",
+		}
+		assert.Equal(t, "ubuntu24", rc.imageOS(ctx))
+	})
+
+	t.Run("falls back to the runs-on label", func(t *testing.T) {
+		rc := createRunsOnRunContext(t, "ubuntu-22.04")
+		rc.Config.Platforms = map[string]string{"ubuntu-22.04": "some-image"}
+		assert.Equal(t, "ubuntu22", rc.imageOS(ctx))
+	})
+
+	t.Run("keeps the historical value for a rolling label with no release", func(t *testing.T) {
+		assert.Equal(t, "ubuntu20", createRunsOnRunContext(t, "ubuntu-latest").imageOS(ctx))
+	})
+
+	t.Run("is empty for the synthetic job of a composite action", func(t *testing.T) {
+		rc := createIfTestRunContext(map[string]*model.Job{"job1": {}})
+		assert.Empty(t, rc.imageOS(ctx))
+	})
+}
+
+func TestRunContextGetRunnerContext(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("adds the runner values the container cannot know", func(t *testing.T) {
+		rc := createRunsOnRunContext(t, "ubuntu-latest")
+		rc.Config.RunnerName = "runner-1"
+
+		runnerContext := rc.getRunnerContext(ctx)
+		assert.Equal(t, "runner-1", runnerContext["name"])
+		assert.Equal(t, "self-hosted", runnerContext["environment"])
+		assert.NotContains(t, runnerContext, "debug")
+	})
+
+	t.Run("reports debug when step debugging is on", func(t *testing.T) {
+		rc := createRunsOnRunContext(t, "ubuntu-latest")
+		rc.Config.Secrets = map[string]string{"ACTIONS_STEP_DEBUG": "true"}
+
+		assert.Equal(t, "1", rc.getRunnerContext(ctx)["debug"])
+	})
+
+	t.Run("keeps the execution environment values", func(t *testing.T) {
+		rc := createRunsOnRunContext(t, "ubuntu-latest")
+		rc.JobContainer = &container.HostEnvironment{TmpDir: "/tmp/act", ToolCache: "/tmp/tool_cache"}
+
+		runnerContext := rc.getRunnerContext(ctx)
+		assert.Equal(t, "/tmp/act", runnerContext["temp"])
+		assert.Equal(t, "/tmp/tool_cache", runnerContext["tool_cache"])
+		assert.NotEmpty(t, runnerContext["os"])
+	})
+}
+
+func TestParentDir(t *testing.T) {
+	assert.Empty(t, parentDir(""))
+	assert.Empty(t, parentDir("repo"))
+	assert.Empty(t, parentDir("/repo"))
+	assert.Equal(t, "/workspace/owner", parentDir("/workspace/owner/repo"))
+	assert.Equal(t, `C:\workspace\owner`, parentDir(`C:\workspace\owner\repo`))
+}
+
+func TestRunContextWithGithubEnvRunnerValues(t *testing.T) {
+	ctx := context.Background()
+	rc := createRunsOnRunContext(t, "ubuntu-latest")
+	rc.Config.RunnerName = "runner-1"
+	rc.Config.Secrets = map[string]string{"ACTIONS_STEP_DEBUG": "true"}
+
+	env := map[string]string{}
+	rc.withGithubEnv(ctx, &model.GithubContext{Workspace: "/workspace/owner/repo"}, env)
+
+	assert.Equal(t, "runner-1", env["RUNNER_NAME"])
+	assert.Equal(t, "self-hosted", env["RUNNER_ENVIRONMENT"])
+	assert.Equal(t, "/workspace/owner", env["RUNNER_WORKSPACE"])
+	assert.Equal(t, "1", env["RUNNER_DEBUG"])
+}

act/runner/runner.go

@@ -92,6 +92,14 @@ type Config struct {
 	InsecureSkipTLS                   bool                         // whether to skip verifying TLS certificate of the Gitea instance
 	MaxParallel                       int                          // max parallel jobs to run across all workflows (0 = no limit, uses CPU count)
 	AllocatePTY                       bool                         // allocate a pseudo-TTY for each step's process
+	RunnerName                        string                       // name this runner registered with, reported as `runner.name`, defaults to the hostname
+}
+
+// RunnerDebug reports whether debug logging is on, exposed as `runner.debug` and
+// RUNNER_DEBUG. Only the secret also makes the reporter keep ::debug:: output, the env
+// is accepted for `exec` and for runners configured with it.
+func (c Config) RunnerDebug() bool {
+	return c.Secrets["ACTIONS_STEP_DEBUG"] == "true" || c.Env["ACTIONS_STEP_DEBUG"] == "true"
 }
 
 // GetToken: Adapt to Gitea
@@ -137,6 +145,11 @@ func New(runnerConfig *Config) (Runner, error) {
 }
 
 func (runner *runnerImpl) configure() (Runner, error) {
+	if runner.config.RunnerName == "" {
+		// Callers that do not register, such as `exec`, still get a `runner.name`.
+		runner.config.RunnerName, _ = os.Hostname()
+	}
+
 	runner.eventJSON = "{}"
 	if runner.config.EventJSON != "" {
 		runner.eventJSON = runner.config.EventJSON

act/runner/step_test.go

@@ -167,6 +167,9 @@ func TestSetupEnv(t *testing.T) {
 	delete((env), "GITHUB_REPOSITORY")
 	delete((env), "GITHUB_REPOSITORY_OWNER")
 	delete((env), "GITHUB_ACTOR")
+	// Host-dependent, asserted in TestRunContextWithGithubEnvRunnerValues instead.
+	delete((env), "RUNNER_NAME")
+	delete((env), "RUNNER_WORKSPACE")
 
 	assert.Equal(t, map[string]string{
 		"ACT":                      "true",
@@ -192,6 +195,7 @@ func TestSetupEnv(t *testing.T) {
 		"GITHUB_WORKFLOW":          "",
 		"INPUT_STEP_WITH":          "with-value",
 		"RC_KEY":                   "rcvalue",
+		"RUNNER_ENVIRONMENT":       "self-hosted",
 		"RUNNER_PERFLOG":           "/dev/null",
 		"RUNNER_TRACKING_ID":       "",
 	}, env)

internal/app/run/runner.go

@@ -474,6 +474,7 @@ func (r *Runner) run(ctx context.Context, task *runnerv1.Task, reporter *report.
 		Vars:                              task.Vars,
 		ValidVolumes:                      r.cfg.Container.ValidVolumes,
 		InsecureSkipTLS:                   r.cfg.Runner.Insecure,
+		RunnerName:                        r.name,
 	}
 
 	rr, err := runner.New(runnerConfig)