diff --git a/flock.go b/flock.go index a66f429..5328796 100644 --- a/flock.go +++ b/flock.go @@ -25,6 +25,22 @@ import ( "time" ) +type Option func(f *Flock) + +// SetFlag sets the flag used to create/open the file. +func SetFlag(flag int) Option { + return func(f *Flock) { + f.flag = flag + } +} + +// SetPermissions sets the OS permissions to set on the file. +func SetPermissions(perm os.FileMode) Option { + return func(f *Flock) { + f.perm = perm + } +} + // Flock is the struct type to handle file locking. All fields are unexported, // with access to some of the fields provided by getter methods (Path() and Locked()). type Flock struct { @@ -33,12 +49,38 @@ type Flock struct { fh *os.File l bool r bool + + // flag is the flag used to create/open the file. + flag int + // perm is the OS permissions to set on the file. + perm os.FileMode } // New returns a new instance of *Flock. The only parameter // it takes is the path to the desired lockfile. -func New(path string) *Flock { - return &Flock{path: path} +func New(path string, opts ...Option) *Flock { + f := &Flock{ + path: path, + perm: os.FileMode(0o600), + } + + // create it if it doesn't exist, and open the file read-only. + flags := os.O_CREATE + switch runtime.GOOS { + case "aix", "solaris", "illumos": + // AIX cannot preform write-lock (i.e. exclusive) on a read-only file. + flags |= os.O_RDWR + default: + flags |= os.O_RDONLY + } + + f.flag = flags + + for _, opt := range opts { + opt(f) + } + + return f } // NewFlock returns a new instance of *Flock. The only parameter @@ -117,23 +159,14 @@ func tryCtx(ctx context.Context, fn func() (bool, error), retryDelay time.Durati func (f *Flock) setFh() error { // open a new os.File instance - // create it if it doesn't exist, and open the file read-only. - flags := os.O_CREATE - switch runtime.GOOS { - case "aix", "solaris", "illumos": - // AIX cannot preform write-lock (i.e. exclusive) on a read-only file. - flags |= os.O_RDWR - default: - flags |= os.O_RDONLY - } - - fh, err := os.OpenFile(f.path, flags, os.FileMode(0o600)) + fh, err := os.OpenFile(f.path, f.flag, f.perm) if err != nil { return err } - // set the filehandle on the struct + // set the file handle on the struct f.fh = fh + return nil }