Use github.com/gofrs/flock for cross platform file locking

Signed-off-by: Patrick Decat <pdecat@gmail.com>

cmd/helm/repo_add.go

@@ -17,14 +17,17 @@ limitations under the License.
 package main
 
 import (
+	"context"
 	"fmt"
 	"io"
-
-	"github.com/spf13/cobra"
-
 	"syscall"
+	"time"
 
 	"golang.org/x/crypto/ssh/terminal"
+
+	"github.com/gofrs/flock"
+	"github.com/spf13/cobra"
+
 	"k8s.io/helm/pkg/getter"
 	"k8s.io/helm/pkg/helm/helmpath"
 	"k8s.io/helm/pkg/repo"
@@ -133,20 +136,13 @@ func addRepository(name, url, username, password string, home helmpath.Home, cer
 	}
 
 	// Lock the repository file for concurrent processes synchronization and re-read its content before updating it
-	fd, err := syscall.Open(home.RepositoryFile(), syscall.O_CREAT|syscall.O_RDWR|syscall.O_CLOEXEC, 0)
-	if err != nil {
-		return err
+	fileLock := flock.New(home.RepositoryFile())
+	lockCtx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
+	defer cancel()
+	locked, err := fileLock.TryLockContext(lockCtx, time.Second)
+	if err == nil && locked {
+		defer fileLock.Unlock()
 	}
-	defer syscall.Close(fd)
-
-	flock := syscall.Flock_t{
-		Type:   syscall.F_WRLCK,
-		Start:  0,
-		Len:    0,
-		Whence: io.SeekStart,
-	}
-
-	syscall.FcntlFlock(uintptr(fd), syscall.F_SETLK, &flock)
 	if err != nil {
 		return err
 	}

glide.lock

@@ -114,6 +114,8 @@ imports:
   - syntax/lexer
   - util/runes
   - util/strings
+- name: github.com/gofrs/flock
+  version: 392e7fae8f1b0bdbd67dad7237d23f618feb6dbb
 - name: github.com/gogo/protobuf
   version: 342cbe0a04158f6dcb03ca0079991a51a4248c02
   subpackages:

glide.yaml

@@ -67,6 +67,8 @@ import:
   - package: github.com/jmoiron/sqlx
     version: ^1.2.0
   - package: github.com/rubenv/sql-migrate
+  - package: github.com/gofrs/flock
+    version: v0.7.1
 
 testImports:
   - package: github.com/stretchr/testify