From 16b86a64a99926aabef5fbae7e47d87322968da5 Mon Sep 17 00:00:00 2001
From: Bengt Brodersen <bengt.brodersen@gmail.com>
Date: Fri, 23 May 2025 10:05:42 +0200
Subject: [PATCH] feat: add cli option to set concurrent jobs count (#2762)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
---
 cmd/input.go         |  1 +
 cmd/root.go          |  2 ++
 pkg/runner/runner.go | 23 +++++++++++++++++------
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/cmd/input.go b/cmd/input.go
index a7ccae8..36c7f7a 100644
--- a/cmd/input.go
+++ b/cmd/input.go
@@ -62,6 +62,7 @@ type Input struct {
 	useNewActionCache                  bool
 	localRepository                    []string
 	listOptions                        bool
+	concurrentJobs                     int
 }
 
 func (i *Input) resolve(path string) string {
diff --git a/cmd/root.go b/cmd/root.go
index 50a2155..87f59ea 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -127,6 +127,7 @@ func createRootCommand(ctx context.Context, input *Input, version string) *cobra
 	rootCmd.PersistentFlags().BoolVarP(&input.useNewActionCache, "use-new-action-cache", "", false, "Enable using the new Action Cache for storing Actions locally")
 	rootCmd.PersistentFlags().StringArrayVarP(&input.localRepository, "local-repository", "", []string{}, "Replaces the specified repository and ref with a local folder (e.g. https://github.com/test/test@v0=/home/act/test or test/test@v0=/home/act/test, the latter matches any hosts or protocols)")
 	rootCmd.PersistentFlags().BoolVar(&input.listOptions, "list-options", false, "Print a json structure of compatible options")
+	rootCmd.PersistentFlags().IntVar(&input.concurrentJobs, "concurrent-jobs", 0, "Maximum number of concurrent jobs to run. Default is the number of CPUs available.")
 	rootCmd.SetArgs(args())
 	return rootCmd
 }
@@ -635,6 +636,7 @@ func newRunCommand(ctx context.Context, input *Input) func(*cobra.Command, []str
 			ReplaceGheActionTokenWithGithubCom: input.replaceGheActionTokenWithGithubCom,
 			Matrix:                             matrixes,
 			ContainerNetworkMode:               docker_container.NetworkMode(input.networkName),
+			ConcurrentJobs:                     input.concurrentJobs,
 		}
 		if input.useNewActionCache || len(input.localRepository) > 0 {
 			if input.actionOfflineMode {
diff --git a/pkg/runner/runner.go b/pkg/runner/runner.go
index 59b92a5..078657e 100644
--- a/pkg/runner/runner.go
+++ b/pkg/runner/runner.go
@@ -61,6 +61,20 @@ type Config struct {
 	Matrix                             map[string]map[string]bool   // Matrix config to run
 	ContainerNetworkMode               docker_container.NetworkMode // the network mode of job containers (the value of --network)
 	ActionCache                        ActionCache                  // Use a custom ActionCache Implementation
+	ConcurrentJobs                     int                          // Number of max concurrent jobs
+}
+
+func (config *Config) GetConcurrentJobs() int {
+	if config.ConcurrentJobs >= 1 {
+		return config.ConcurrentJobs
+	}
+
+	ncpu := runtime.NumCPU()
+	log.Debugf("Detected CPUs: %d", ncpu)
+	if ncpu > 1 {
+		return ncpu
+	}
+	return 1
 }
 
 type caller struct {
@@ -195,12 +209,9 @@ func (runner *runnerImpl) NewPlanExecutor(plan *model.Plan) common.Executor {
 				}
 				pipeline = append(pipeline, common.NewParallelExecutor(maxParallel, stageExecutor...))
 			}
-			ncpu := runtime.NumCPU()
-			if 1 > ncpu {
-				ncpu = 1
-			}
-			log.Debugf("Detected CPUs: %d", ncpu)
-			return common.NewParallelExecutor(ncpu, pipeline...)(ctx)
+
+			log.Debugf("PlanExecutor concurrency: %d", runner.config.GetConcurrentJobs())
+			return common.NewParallelExecutor(runner.config.GetConcurrentJobs(), pipeline...)(ctx)
 		})
 	}