api/message: for codec implementations, define a function instead of global variables.

api/message/msgpack/codec.go

@@ -8,27 +8,28 @@ import (
 	"github.com/eosswedenorg/thalos/api/message"
 )
 
-var mh codec.MsgpackHandle
-
-func encode(a any) ([]byte, error) {
-	var b []byte
-	return b, codec.NewEncoderBytes(&b, &mh).Encode(a)
-}
-
-func decode(b []byte, a any) error {
-	return codec.NewDecoderBytes(b, &mh).Decode(a)
-}
-
-func init() {
-	mh.MapType = reflect.TypeOf(map[string]any(nil))
-	mh.Canonical = true
+func createCodec() message.Codec {
+	// Create handler.
+	handle := codec.MsgpackHandle{}
+	handle.MapType = reflect.TypeOf(map[string]any(nil))
+	handle.Canonical = true
 
 	// Wierd name but this is needed for the newest version of msgpack
 	// that has support for time and string datatypes etc.
-	mh.WriteExt = true
+	handle.WriteExt = true
 
-	message.RegisterCodec("msgpack", message.Codec{
-		Encoder: encode,
-		Decoder: decode,
-	})
+	return message.Codec{
+		Encoder: func(a any) ([]byte, error) {
+			var b []byte
+			return b, codec.NewEncoderBytes(&b, &handle).Encode(a)
+		},
+		Decoder: func(b []byte, a any) error {
+			return codec.NewDecoderBytes(b, &handle).Decode(a)
+		},
+	}
+}
+
+func init() {
+	// Register codec.
+	message.RegisterCodec("msgpack", createCodec())
 }