feat: replace parallel with a semaphore

3 files changed, 68 insertions, 43 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..61ead86
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/vendor
diff --git a/Gopkg.lock b/Gopkg.lock
index 19691af..86ff3bb 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -3,13 +3,19 @@
 
 [[projects]]
   branch = "master"
-  name = "github.com/neelance/parallel"
-  packages = ["."]
-  revision = "4de9ce63d14c18517a79efe69e10e99d32c850c3"
+  name = "golang.org/x/net"
+  packages = ["context"]
+  revision = "d866cfc389cec985d6fda2859936a575a55a3ab6"
+
+[[projects]]
+  branch = "master"
+  name = "golang.org/x/sync"
+  packages = ["semaphore"]
+  revision = "fd80eb99c8f653c847d294a001bdf2a3a6f768f5"
 
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "5cee123e66d33e8e63ab1f1a2ae68b744798e2093d92a855bfa52f7465b4c6ca"
+  inputs-digest = "1b7a27daae87f4f213b3475a08fd7367804c2755750bf27adb8c32ada7c9bdae"
   solver-name = "gps-cdcl"
   solver-version = 1
diff --git a/main.go b/main.go
index ea2942c..a990cc3 100644
--- a/main.go
+++ b/main.go
@@ -11,7 +11,7 @@ import (
 	"path/filepath"
 	"runtime"
 
-	"github.com/neelance/parallel"
+	"golang.org/x/sync/semaphore"
 )
 
 type Arch string
@@ -114,46 +114,64 @@ func main() {
 		os.Exit(-1)
 	}
 
-	parallelJobs := runtime.NumCPU()
-	par := parallel.NewRun(parallelJobs)
+	var (
+		parallelJobs = runtime.NumCPU()
+		sem          = semaphore.NewWeighted(int64(parallelJobs))
+		out          = make([]error, len(platforms)*len(packages))
+		ctx          = context.Background()
+	)
+
 	fmt.Printf("info: running bakelite with %d jobs\n", parallelJobs)
 
-	for _, platform := range platforms {
-		for _, pkg := range packages {
-			par.Acquire()
-			go func(platform Platform, pkg string) {
-				defer par.Release()
-				name := fmt.Sprintf("%s-%s-%s", filepath.Base(pkg), platform.OS, platform.Arch)
-				env := kvs{
-					"GOOS":   string(platform.OS),
-					"GOARCH": string(platform.Arch),
-					"GOROOT": os.Getenv("GOROOT"),
-					"GOPATH": os.Getenv("GOPATH"),
-				}
-
-				if cgo {
-					env["CGO_ENABLED"] = "1"
-				} else {
-					env["CGO_ENABLED"] = "0"
-				}
-
-				var stdout bytes.Buffer
-				var stderr bytes.Buffer
-
-				cmd := exec.CommandContext(context.Background(), "go", "build", "-o", name, pkg)
-				cmd.Env = env.Strings()
-				cmd.Stdout = &stdout
-				cmd.Stderr = &stderr
-
-				fmt.Printf("info: Running build for %s @ %s/%s…\n", pkg, platform.OS, platform.Arch)
-				err := cmd.Run()
-
-				if err != nil {
-					log.Printf("fatal: There was an error! err='%s' stdout='%s' stderr='%s'", err, stdout.String(), stderr.String())
-					os.Exit(-1)
-				}
-			}(platform, pkg)
+	for i, platform := range platforms {
+		for j, pkg := range packages {
+			if err := sem.Acquire(ctx, 1); err != nil {
+				log.Printf("failed to acquire semaphore: %s", err)
+				break
+			}
+
+			go func(i int, j int, platform Platform, pkg string) {
+				defer sem.Release(1)
+				out[i*j] = build(ctx, platform, pkg)
+			}(i, j, platform, pkg)
 		}
 	}
-	par.Wait()
+
+	if err := sem.Acquire(ctx, int64(parallelJobs)); err != nil {
+		log.Printf("failed to acquire semaphore: %s", err)
+	}
+}
+
+func build(ctx context.Context, platform Platform, pkg string) error {
+	name := fmt.Sprintf("%s-%s-%s", filepath.Base(pkg), platform.OS, platform.Arch)
+
+	env := kvs{
+		"GOOS":   string(platform.OS),
+		"GOARCH": string(platform.Arch),
+		"GOROOT": os.Getenv("GOROOT"),
+		"GOPATH": os.Getenv("GOPATH"),
+	}
+
+	if cgo {
+		env["CGO_ENABLED"] = "1"
+	} else {
+		env["CGO_ENABLED"] = "0"
+	}
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+
+	cmd := exec.CommandContext(context.Background(), "go", "build", "-o", name, pkg)
+	cmd.Env = env.Strings()
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+
+	fmt.Printf("info: Running build for %s @ %s/%s…\n", pkg, platform.OS, platform.Arch)
+	err := cmd.Run()
+
+	if err != nil {
+		log.Printf("fatal: There was an error! err='%s' stdout='%s' stderr='%s'", err, stdout.String(), stderr.String())
+	}
+
+	return err
 }