feat: add parallel flag (#114)

* add parallel flag

pkg/runner/run_context.go

@@ -27,6 +27,7 @@ import (
 	"github.com/docker/go-connections/nat"
 	"github.com/opencontainers/selinux/go-selinux"
 	"github.com/sirupsen/logrus"
+	"golang.org/x/sync/semaphore"
 )
 
 // RunContext contains info about current job
@@ -772,12 +773,22 @@ func (rc *RunContext) Executor() (common.Executor, error) {
 		}
 	}
 
+	if rc.Config != nil && rc.Config.Parallel > 0 && rc.Config.semaphore == nil {
+		rc.Config.semaphore = semaphore.NewWeighted(int64(rc.Config.Parallel))
+	}
+
 	return func(ctx context.Context) error {
 		res, err := rc.isEnabled(ctx)
 		if err != nil {
 			return err
 		}
 		if res {
+			if jobType == model.JobTypeDefault && rc.Config != nil && rc.Config.Parallel > 0 && rc.Config.semaphore != nil {
+				if err := rc.Config.semaphore.Acquire(ctx, 1); err != nil {
+					return fmt.Errorf("failed to acquire semaphore: %w", err)
+				}
+				defer rc.Config.semaphore.Release(1)
+			}
 			return executor(ctx)
 		}
 		return nil

pkg/runner/runner.go

@@ -12,6 +12,7 @@ import (
 	"github.com/actions-oss/act-cli/pkg/model"
 	docker_container "github.com/docker/docker/api/types/container"
 	log "github.com/sirupsen/logrus"
+	"golang.org/x/sync/semaphore"
 )
 
 // Runner provides capabilities to run GitHub actions
@@ -68,6 +69,8 @@ type Config struct {
 	HostEnvironmentDir                 string                       // Custom folder for host environment, parallel jobs must be 1
 
 	CustomExecutor map[model.JobType]func(*RunContext) common.Executor // Custom executor to run jobs
+	semaphore      *semaphore.Weighted
+	Parallel       int // Number of parallel jobs to run
 }
 
 func (runnerConfig *Config) GetGitHubServerURL() string {
@@ -234,6 +237,9 @@ func (runner *runnerImpl) NewPlanExecutor(plan *model.Plan) common.Executor {
 				}
 				pipeline = append(pipeline, common.NewParallelExecutor(maxParallel, stageExecutor...))
 			}
+			if runner.config.Parallel != 0 {
+				return common.NewParallelExecutor(len(pipeline), pipeline...)(ctx)
+			}
 			ncpu := runtime.NumCPU()
 			if 1 > ncpu {
 				ncpu = 1

pkg/runner/runner_test.go

@@ -193,6 +193,7 @@ func (j *TestJobFileInfo) runTest(ctx context.Context, t *testing.T, cfg *Config
 		ContainerArchitecture: cfg.ContainerArchitecture,
 		Matrix:                cfg.Matrix,
 		ActionCache:           cfg.ActionCache,
+		Parallel:              cfg.Parallel,
 	}
 
 	runner, err := New(runnerConfig)
@@ -338,7 +339,8 @@ func TestRunEvent(t *testing.T) {
 	for _, table := range tables {
 		t.Run(table.workflowPath, func(t *testing.T) {
 			config := &Config{
-				Secrets: table.secrets,
+				Secrets:  table.secrets,
+				Parallel: 8,
 			}
 
 			eventFile := filepath.Join(workdir, table.workflowPath, "event.json")