fs: add --metadata/-M flag to control whether metadata is copied

fs/config.go

@@ -134,6 +134,7 @@ type ConfigInfo struct {
 	HumanReadable          bool
 	KvLockTime             time.Duration // maximum time to keep key-value database locked by process
 	DisableHTTPKeepAlives  bool
+	Metadata               bool
 }
 
 // NewConfig creates a new config with everything set to the default

fs/config/configflags/configflags.go

@@ -140,6 +140,7 @@ func AddFlags(ci *fs.ConfigInfo, flagSet *pflag.FlagSet) {
 	flags.BoolVarP(flagSet, &ci.HumanReadable, "human-readable", "", ci.HumanReadable, "Print numbers in a human-readable format, sizes with suffix Ki|Mi|Gi|Ti|Pi")
 	flags.DurationVarP(flagSet, &ci.KvLockTime, "kv-lock-time", "", ci.KvLockTime, "Maximum time to keep key-value database locked by process")
 	flags.BoolVarP(flagSet, &ci.DisableHTTPKeepAlives, "disable-http-keep-alives", "", ci.DisableHTTPKeepAlives, "Disable HTTP keep-alives and use each connection once.")
+	flags.BoolVarP(flagSet, &ci.Metadata, "metadata", "M", ci.Metadata, "If set, preserve metadata when copying objects")
 }
 
 // ParseHeaders converts the strings passed in via the header flags into HTTPOptions

fs/metadata.go

@@ -68,8 +68,14 @@ func GetMetadata(ctx context.Context, o ObjectInfo) (metadata Metadata, err erro
 
 // GetMetadataOptions from an ObjectInfo and merge it with any in options
 //
+// If --metadata isn't in use it will return nil
+//
 // If the object has no metadata then metadata will be nil
 func GetMetadataOptions(ctx context.Context, o ObjectInfo, options []OpenOption) (metadata Metadata, err error) {
+	ci := GetConfig(ctx)
+	if !ci.Metadata {
+		return nil, nil
+	}
 	metadata, err = GetMetadata(ctx, o)
 	if err != nil {
 		return nil, err

fstest/fstests/fstests.go

@@ -206,6 +206,15 @@ func PutTestContentsMetadata(ctx context.Context, t *testing.T, f fs.Fs, file *f
 		file.Size = int64(buf.Len())
 		obji := object.NewStaticObjectInfo(file.Path, file.ModTime, file.Size, true, nil, nil)
 		if mimeType != "" || metadata != nil {
+			// force the --metadata flag on temporarily
+			if metadata != nil {
+				ci := fs.GetConfig(ctx)
+				previousMetadata := ci.Metadata
+				ci.Metadata = true
+				defer func() {
+					ci.Metadata = previousMetadata
+				}()
+			}
 			obji = overrideMimeType(obji, mimeType, metadata)
 		}
 		obj, err = f.Put(ctx, in, obji)