🌅 complete OS X keychain implementation.

Signed-off-by: David Calavera <david.calavera@gmail.com>

plugin/plugin.go

@@ -0,0 +1,38 @@
+package plugin
+
+import (
+	"net/rpc"
+
+	"github.com/calavera/docker-credential-helpers/credentials"
+	"github.com/hashicorp/go-plugin"
+)
+
+var handshakeConfig = plugin.HandshakeConfig{
+	ProtocolVersion:  1,
+	MagicCookieKey:   "DOCKER_CREDENTIAL_PLUGIN",
+	MagicCookieValue: "nyzGgJQpfOYO$oUVHo4RsLaYaNmCqeWLEqZnZG}peMVq4nXdFp",
+}
+
+type credentialsPlugin struct {
+	helper credentials.Helper
+}
+
+func (p *credentialsPlugin) Server(*plugin.MuxBroker) (interface{}, error) {
+	return p, nil
+}
+
+func (*credentialsPlugin) Client(b *plugin.MuxBroker, c *rpc.Client) (interface{}, error) {
+	return nil, nil
+}
+
+// Serve initializes the socket connection to a store helper.
+func Serve(helper credentials.Helper) {
+	pluginMap := map[string]plugin.Plugin{
+		"credentials": &credentialsPlugin{helper},
+	}
+
+	plugin.Serve(&plugin.ServeConfig{
+		HandshakeConfig: handshakeConfig,
+		Plugins:         pluginMap,
+	})
+}