close #6

Author: Andrew Pennebaker

cmd/tug/main.go

@@ -17,6 +17,7 @@ var flagExcludeArch = flag.String("exclude-arch", "", "exclude architecture targ
 var flagGetPlatforms = flag.Bool("get-platforms", false, "Get available buildx platforms")
 var flagLs = flag.String("ls", "", "List buildx cache for the given image name, of the form name[:tag]")
 var flagT = flag.String("t", "", "Docker image name, of the form name[:tag]")
+var flagJobs = flag.Int("jobs", 4, "Number of concurrent build jobs. Zero indicates no restriction.")
 var flagClean = flag.Bool("clean", false, "Remove junk resources (buildx cache; buildx builder)")
 var flagHelp = flag.Bool("help", false, "Show usage information")
 var flagVersion = flag.Bool("version", false, "Show version information")
@@ -55,11 +56,6 @@ func main() {
 		os.Exit(0)
 	}
 
-	if err := tug.EnsureTugBuilder(); err != nil {
-		fmt.Fprintf(os.Stderr, "%v", err)
-		os.Exit(1)
-	}
-
 	job, err := tug.NewJob()
 
 	if err != nil {
@@ -73,6 +69,7 @@ func main() {
 	}
 
 	job.ImageName = flagT
+	job.BatchSize = *flagJobs
 	job.Push = *flagPush
 	job.OsExclusions = strings.Split(*flagExcludeOS, " ")
 	job.ArchExclusions = strings.Split(*flagExcludeArch, " ")

job.go

@@ -41,11 +41,15 @@ type Job struct {
 	// of the form name[:tag].
 	ImageName *string
 
+	// BatchSize restricts the number of concurrent builds.
+	// Zero indicates no restriction.
+	BatchSize int
+
 	// Directory denotes the Docker build directory (defaults behavior assumes the current working directory).
 	Directory string
 }
 
-// NewJob generates a default Job.
+// NewJob initializes tug and generates a default Job.
 func NewJob() (*Job, error) {
 	platforms, err := AvailablePlatforms()
 
@@ -62,8 +66,8 @@ func NewJob() (*Job, error) {
 	return &Job{Builder: TugBuilderName, Platforms: platforms, Directory: cwd}, nil
 }
 
-// Run executes a Job.
-func (o Job) Run() error {
+// runBatch executes a batch of platforms.
+func (o Job) runBatch() error {
 	cmd := exec.Command("docker")
 	cmd.Env = os.Environ()
 	cmd.Stderr = os.Stderr
@@ -79,6 +83,39 @@ func (o Job) Run() error {
 
 	var platformPairs []string
 
+	for _, platform := range o.Platforms {
+		platformPairs = append(platformPairs, platform.Format())
+	}
+
+	cmd.Args = append(cmd.Args, "--platform")
+
+	if o.LoadPlatform == nil {
+		cmd.Args = append(cmd.Args, strings.Join(platformPairs, ","))
+	} else {
+		cmd.Args = append(cmd.Args, *o.LoadPlatform)
+		cmd.Args = append(cmd.Args, "--load")
+	}
+
+	if o.Push {
+		cmd.Args = append(cmd.Args, "--push")
+	}
+
+	cmd.Args = append(cmd.Args, "-t")
+	cmd.Args = append(cmd.Args, *o.ImageName)
+
+	cmd.Args = append(cmd.Args, o.Directory)
+
+	if o.Debug {
+		log.Printf("Command: %v\n", cmd)
+	}
+
+	return cmd.Run()
+}
+
+// Run schedules builds.
+func (o Job) Run() error {
+	var platforms []Platform
+
 	for _, platform := range o.Platforms {
 		var excludedOs bool
 
@@ -106,30 +143,35 @@ func (o Job) Run() error {
 			continue
 		}
 
-		platformPairs = append(platformPairs, platform.Format())
+		platforms = append(platforms, platform)
 	}
 
-	cmd.Args = append(cmd.Args, "--platform")
+	o.Platforms = platforms
 
-	if o.LoadPlatform == nil {
-		cmd.Args = append(cmd.Args, strings.Join(platformPairs, ","))
-	} else {
-		cmd.Args = append(cmd.Args, *o.LoadPlatform)
-		cmd.Args = append(cmd.Args, "--load")
-	}
+	batchSize := o.BatchSize
 
-	if o.Push {
-		cmd.Args = append(cmd.Args, "--push")
+	if batchSize == 0 {
+		return o.runBatch()
 	}
 
-	cmd.Args = append(cmd.Args, "-t")
-	cmd.Args = append(cmd.Args, *o.ImageName)
+	var platformGroups [][]Platform
 
-	cmd.Args = append(cmd.Args, o.Directory)
+	for len(o.Platforms) != 0 {
+		if len(o.Platforms) < batchSize {
+			batchSize = len(o.Platforms)
+		}
 
-	if o.Debug {
-		log.Printf("Command: %v\n", cmd)
+		platformGroups = append(platformGroups, o.Platforms[0:batchSize])
+		o.Platforms = o.Platforms[batchSize:]
 	}
 
-	return cmd.Run()
+	for _, platformGroup := range platformGroups {
+		o.Platforms = platformGroup
+
+		if err := o.runBatch(); err != nil {
+			return err
+		}
+	}
+
+	return nil
 }

platform.go

@@ -145,8 +145,12 @@ func EnsureTugBuilder() error {
 	return EnsureTugBuilderBootstrapped()
 }
 
-// AvailablePlatforms reports the available buildx platforms.
+// AvailablePlatforms initializes tug and reports the available buildx platforms.
 func AvailablePlatforms() ([]Platform, error) {
+	if err := EnsureTugBuilder(); err != nil {
+		return nil, err
+	}
+
 	cmd := exec.Command("docker")
 	cmd.Args = []string{"docker", "buildx", "inspect", TugBuilderName}
 	cmd.Env = os.Environ()