feat: allow to spawn and run a local reusable workflow (nektos#1423)

* feat: allow to spawn and run a local reusable workflow

This change contains the ability to parse/plan/run a local
reusable workflow.
There are still numerous things missing:

- inputs
- secrets
- outputs

* feat: add workflow_call inputs

* test: improve inputs test

* feat: add input defaults

* feat: allow expressions in inputs

* feat: use context specific expression evaluator

* refactor: prepare for better re-usability

* feat: add secrets for reusable workflows

* test: use secrets during test run

* feat: handle reusable workflow outputs

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/model/workflow.go

@@ -100,6 +100,44 @@ func (w *Workflow) WorkflowDispatchConfig() *WorkflowDispatch {
 	return &config
 }
 
+type WorkflowCallInput struct {
+	Description string `yaml:"description"`
+	Required    bool   `yaml:"required"`
+	Default     string `yaml:"default"`
+	Type        string `yaml:"type"`
+}
+
+type WorkflowCallOutput struct {
+	Description string `yaml:"description"`
+	Value       string `yaml:"value"`
+}
+
+type WorkflowCall struct {
+	Inputs  map[string]WorkflowCallInput  `yaml:"inputs"`
+	Outputs map[string]WorkflowCallOutput `yaml:"outputs"`
+}
+
+func (w *Workflow) WorkflowCallConfig() *WorkflowCall {
+	if w.RawOn.Kind != yaml.MappingNode {
+		return nil
+	}
+
+	var val map[string]yaml.Node
+	err := w.RawOn.Decode(&val)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var config WorkflowCall
+	node := val["workflow_call"]
+	err = node.Decode(&config)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	return &config
+}
+
 // Job is the structure of one job in a workflow
 type Job struct {
 	Name           string                    `yaml:"name"`
@@ -115,6 +153,8 @@ type Job struct {
 	Defaults       Defaults                  `yaml:"defaults"`
 	Outputs        map[string]string         `yaml:"outputs"`
 	Uses           string                    `yaml:"uses"`
+	With           map[string]interface{}    `yaml:"with"`
+	RawSecrets     yaml.Node                 `yaml:"secrets"`
 	Result         string
 }
 
@@ -169,6 +209,34 @@ func (s Strategy) GetFailFast() bool {
 	return failFast
 }
 
+func (j *Job) InheritSecrets() bool {
+	if j.RawSecrets.Kind != yaml.ScalarNode {
+		return false
+	}
+
+	var val string
+	err := j.RawSecrets.Decode(&val)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	return val == "inherit"
+}
+
+func (j *Job) Secrets() map[string]string {
+	if j.RawSecrets.Kind != yaml.MappingNode {
+		return nil
+	}
+
+	var val map[string]string
+	err := j.RawSecrets.Decode(&val)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	return val
+}
+
 // Container details for the job
 func (j *Job) Container() *ContainerSpec {
 	var val *ContainerSpec

pkg/runner/expression.go

@@ -55,7 +55,7 @@ func (rc *RunContext) NewExpressionEvaluatorWithEnv(ctx context.Context, env map
 		// todo: should be unavailable
 		// but required to interpolate/evaluate the step outputs on the job
 		Steps:    rc.getStepsContext(),
-		Secrets:  rc.Config.Secrets,
+		Secrets:  getWorkflowSecrets(ctx, rc),
 		Strategy: strategy,
 		Matrix:   rc.Matrix,
 		Needs:    using,
@@ -101,7 +101,7 @@ func (rc *RunContext) NewStepExpressionEvaluator(ctx context.Context, step step)
 		Env:      *step.getEnv(),
 		Job:      rc.getJobContext(),
 		Steps:    rc.getStepsContext(),
-		Secrets:  rc.Config.Secrets,
+		Secrets:  getWorkflowSecrets(ctx, rc),
 		Strategy: strategy,
 		Matrix:   rc.Matrix,
 		Needs:    using,
@@ -315,6 +315,8 @@ func rewriteSubExpression(ctx context.Context, in string, forceFormat bool) (str
 func getEvaluatorInputs(ctx context.Context, rc *RunContext, step step, ghc *model.GithubContext) map[string]interface{} {
 	inputs := map[string]interface{}{}
 
+	setupWorkflowInputs(ctx, &inputs, rc)
+
 	var env map[string]string
 	if step != nil {
 		env = *step.getEnv()
@@ -347,3 +349,54 @@ func getEvaluatorInputs(ctx context.Context, rc *RunContext, step step, ghc *mod
 
 	return inputs
 }
+
+func setupWorkflowInputs(ctx context.Context, inputs *map[string]interface{}, rc *RunContext) {
+	if rc.caller != nil {
+		config := rc.Run.Workflow.WorkflowCallConfig()
+
+		for name, input := range config.Inputs {
+			value := rc.caller.runContext.Run.Job().With[name]
+			if value != nil {
+				if str, ok := value.(string); ok {
+					// evaluate using the calling RunContext (outside)
+					value = rc.caller.runContext.ExprEval.Interpolate(ctx, str)
+				}
+			}
+
+			if value == nil && config != nil && config.Inputs != nil {
+				value = input.Default
+				if rc.ExprEval != nil {
+					if str, ok := value.(string); ok {
+						// evaluate using the called RunContext (inside)
+						value = rc.ExprEval.Interpolate(ctx, str)
+					}
+				}
+			}
+
+			(*inputs)[name] = value
+		}
+	}
+}
+
+func getWorkflowSecrets(ctx context.Context, rc *RunContext) map[string]string {
+	if rc.caller != nil {
+		job := rc.caller.runContext.Run.Job()
+		secrets := job.Secrets()
+
+		if secrets == nil && job.InheritSecrets() {
+			secrets = rc.caller.runContext.Config.Secrets
+		}
+
+		if secrets == nil {
+			secrets = map[string]string{}
+		}
+
+		for k, v := range secrets {
+			secrets[k] = rc.caller.runContext.ExprEval.Interpolate(ctx, v)
+		}
+
+		return secrets
+	}
+
+	return rc.Config.Secrets
+}

pkg/runner/job_executor.go

@@ -104,6 +104,8 @@ func newJobExecutor(info jobInfo, sf stepFactory, rc *RunContext) common.Executo
 			err = info.stopContainer()(ctx)
 		}
 		setJobResult(ctx, info, rc, jobError == nil)
+		setJobOutputs(ctx, rc)
+
 		return err
 	})
 
@@ -135,9 +137,27 @@ func setJobResult(ctx context.Context, info jobInfo, rc *RunContext, success boo
 		jobResultMessage = "failed"
 	}
 	info.result(jobResult)
+	if rc.caller != nil {
+		// set reusable workflow job result
+		rc.caller.runContext.result(jobResult)
+	}
 	logger.WithField("jobResult", jobResult).Infof("\U0001F3C1  Job %s", jobResultMessage)
 }
 
+func setJobOutputs(ctx context.Context, rc *RunContext) {
+	if rc.caller != nil {
+		// map outputs for reusable workflows
+		callerOutputs := make(map[string]string)
+
+		ee := rc.NewExpressionEvaluator(ctx)
+		for k, v := range rc.Run.Job().Outputs {
+			callerOutputs[k] = ee.Interpolate(ctx, v)
+		}
+
+		rc.caller.runContext.Run.Job().Outputs = callerOutputs
+	}
+}
+
 func useStepLogger(rc *RunContext, stepModel *model.Step, stage stepStage, executor common.Executor) common.Executor {
 	return func(ctx context.Context) error {
 		ctx = withStepLogger(ctx, stepModel.ID, rc.ExprEval.Interpolate(ctx, stepModel.String()), stage.String())

pkg/runner/job_executor_test.go

@@ -15,15 +15,15 @@ import (
 
 func TestJobExecutor(t *testing.T) {
 	tables := []TestJobFileInfo{
-		{workdir, "uses-and-run-in-one-step", "push", "Invalid run/uses syntax for job:test step:Test", platforms},
-		{workdir, "uses-github-empty", "push", "Expected format {org}/{repo}[/path]@ref", platforms},
-		{workdir, "uses-github-noref", "push", "Expected format {org}/{repo}[/path]@ref", platforms},
-		{workdir, "uses-github-root", "push", "", platforms},
-		{workdir, "uses-github-path", "push", "", platforms},
-		{workdir, "uses-docker-url", "push", "", platforms},
-		{workdir, "uses-github-full-sha", "push", "", platforms},
-		{workdir, "uses-github-short-sha", "push", "Unable to resolve action `actions/hello-world-docker-action@b136eb8`, the provided ref `b136eb8` is the shortened version of a commit SHA, which is not supported. Please use the full commit SHA `b136eb8894c5cb1dd5807da824be97ccdf9b5423` instead", platforms},
-		{workdir, "job-nil-step", "push", "invalid Step 0: missing run or uses key", platforms},
+		{workdir, "uses-and-run-in-one-step", "push", "Invalid run/uses syntax for job:test step:Test", platforms, secrets},
+		{workdir, "uses-github-empty", "push", "Expected format {org}/{repo}[/path]@ref", platforms, secrets},
+		{workdir, "uses-github-noref", "push", "Expected format {org}/{repo}[/path]@ref", platforms, secrets},
+		{workdir, "uses-github-root", "push", "", platforms, secrets},
+		{workdir, "uses-github-path", "push", "", platforms, secrets},
+		{workdir, "uses-docker-url", "push", "", platforms, secrets},
+		{workdir, "uses-github-full-sha", "push", "", platforms, secrets},
+		{workdir, "uses-github-short-sha", "push", "Unable to resolve action `actions/hello-world-docker-action@b136eb8`, the provided ref `b136eb8` is the shortened version of a commit SHA, which is not supported. Please use the full commit SHA `b136eb8894c5cb1dd5807da824be97ccdf9b5423` instead", platforms, secrets},
+		{workdir, "job-nil-step", "push", "invalid Step 0: missing run or uses key", platforms, secrets},
 	}
 	// These tests are sufficient to only check syntax.
 	ctx := common.WithDryrun(context.Background(), true)

pkg/runner/reusable_workflow.go

@@ -0,0 +1,45 @@
+package runner
+
+import (
+	"fmt"
+	"path"
+
+	"github.com/nektos/act/pkg/common"
+	"github.com/nektos/act/pkg/model"
+)
+
+func newLocalReusableWorkflowExecutor(rc *RunContext) common.Executor {
+	return newReusableWorkflowExecutor(rc, rc.Config.Workdir)
+}
+
+func newRemoteReusableWorkflowExecutor(rc *RunContext) common.Executor {
+	return common.NewErrorExecutor(fmt.Errorf("remote reusable workflows are currently not supported (see https://github.com/nektos/act/issues/826 for updates)"))
+}
+
+func newReusableWorkflowExecutor(rc *RunContext, directory string) common.Executor {
+	planner, err := model.NewWorkflowPlanner(path.Join(directory, rc.Run.Job().Uses), true)
+	if err != nil {
+		return common.NewErrorExecutor(err)
+	}
+
+	plan := planner.PlanEvent("workflow_call")
+
+	runner, err := NewReusableWorkflowRunner(rc)
+	if err != nil {
+		return common.NewErrorExecutor(err)
+	}
+
+	return runner.NewPlanExecutor(plan)
+}
+
+func NewReusableWorkflowRunner(rc *RunContext) (Runner, error) {
+	runner := &runnerImpl{
+		config:    rc.Config,
+		eventJSON: rc.EventJSON,
+		caller: &caller{
+			runContext: rc,
+		},
+	}
+
+	return runner.configure()
+}

pkg/runner/run_context.go

@@ -46,6 +46,7 @@ type RunContext struct {
 	Parent              *RunContext
 	Masks               []string
 	cleanUpJobContainer common.Executor
+	caller              *caller // job calling this RunContext (reusable workflows)
 }
 
 func (rc *RunContext) AddMask(mask string) {
@@ -58,7 +59,13 @@ type MappableOutput struct {
 }
 
 func (rc *RunContext) String() string {
-	return fmt.Sprintf("%s/%s", rc.Run.Workflow.Name, rc.Name)
+	name := fmt.Sprintf("%s/%s", rc.Run.Workflow.Name, rc.Name)
+	if rc.caller != nil {
+		// prefix the reusable workflow with the caller job
+		// this is required to create unique container names
+		name = fmt.Sprintf("%s/%s", rc.caller.runContext.Run.JobID, name)
+	}
+	return name
 }
 
 // GetEnv returns the env for the context
@@ -399,16 +406,25 @@ func (rc *RunContext) steps() []*model.Step {
 
 // Executor returns a pipeline executor for all the steps in the job
 func (rc *RunContext) Executor() common.Executor {
+	var executor common.Executor
+
+	switch rc.Run.Job().Type() {
+	case model.JobTypeDefault:
+		executor = newJobExecutor(rc, &stepFactoryImpl{}, rc)
+	case model.JobTypeReusableWorkflowLocal:
+		executor = newLocalReusableWorkflowExecutor(rc)
+	case model.JobTypeReusableWorkflowRemote:
+		executor = newRemoteReusableWorkflowExecutor(rc)
+	}
+
 	return func(ctx context.Context) error {
-		isEnabled, err := rc.isEnabled(ctx)
+		res, err := rc.isEnabled(ctx)
 		if err != nil {
 			return err
 		}
-
-		if isEnabled {
-			return newJobExecutor(rc, &stepFactoryImpl{}, rc)(ctx)
+		if res {
+			return executor(ctx)
 		}
-
 		return nil
 	}
 }
@@ -458,6 +474,10 @@ func (rc *RunContext) isEnabled(ctx context.Context) (bool, error) {
 		return false, nil
 	}
 
+	if job.Type() != model.JobTypeDefault {
+		return true, nil
+	}
+
 	img := rc.platformImage(ctx)
 	if img == "" {
 		if job.RunsOn() == nil {

pkg/runner/runner.go

@@ -53,9 +53,14 @@ type Config struct {
 	ReplaceGheActionTokenWithGithubCom string            // Token of private action repo on GitHub.
 }
 
+type caller struct {
+	runContext *RunContext
+}
+
 type runnerImpl struct {
 	config    *Config
 	eventJSON string
+	caller    *caller // the job calling this runner (caller of a reusable workflow)
 }
 
 // New Creates a new Runner
@@ -64,8 +69,12 @@ func New(runnerConfig *Config) (Runner, error) {
 		config: runnerConfig,
 	}
 
+	return runner.configure()
+}
+
+func (runner *runnerImpl) configure() (Runner, error) {
 	runner.eventJSON = "{}"
-	if runnerConfig.EventPath != "" {
+	if runner.config.EventPath != "" {
 		log.Debugf("Reading event.json from %s", runner.config.EventPath)
 		eventJSONBytes, err := os.ReadFile(runner.config.EventPath)
 		if err != nil {
@@ -89,10 +98,6 @@ func (runner *runnerImpl) NewPlanExecutor(plan *model.Plan) common.Executor {
 				stageExecutor := make([]common.Executor, 0)
 				job := run.Job()
 
-				if job.Uses != "" {
-					return fmt.Errorf("reusable workflows are currently not supported (see https://github.com/nektos/act/issues/826 for updates)")
-				}
-
 				if job.Strategy != nil {
 					strategyRc := runner.newRunContext(ctx, run, nil)
 					if err := strategyRc.NewExpressionEvaluator(ctx).EvaluateYamlNode(ctx, &job.Strategy.RawMatrix); err != nil {
@@ -161,8 +166,10 @@ func (runner *runnerImpl) newRunContext(ctx context.Context, run *model.Run, mat
 		EventJSON:   runner.eventJSON,
 		StepResults: make(map[string]*model.StepResult),
 		Matrix:      matrix,
+		caller:      runner.caller,
 	}
 	rc.ExprEval = rc.NewExpressionEvaluator(ctx)
 	rc.Name = rc.ExprEval.Interpolate(ctx, run.String())
+
 	return rc
 }