cli: debug decode-key to support base64

Previously decode-key supported hex encoded keys. When using
json serialization of descriptors and recovery plans you need
to decode keys that are base64 encoded and may be non mvcc.
This patch adds flags to select formats and keys types to the
decoded.
The default mode stays the same so any existing tooling will
work as expected.

Release note: None

pkg/cli/debug.go

@@ -528,19 +528,29 @@ func runDebugRangeDescriptors(cmd *cobra.Command, args []string) error {
 	})
 }
 
+var decodeKeyOptions struct {
+	useBase64 bool
+}
+
 var debugDecodeKeyCmd = &cobra.Command{
 	Use:   "decode-key",
 	Short: "decode <key>",
 	Long: `
-Decode a hexadecimal-encoded key and pretty-print it. For example:
+Decode a hexadecimal or base64 encoded key and pretty-print it. For example:
 
 	$ decode-key BB89F902ADB43000151C2D1ED07DE6C009
 	/Table/51/1/44938288/1521140384.514565824,0
 `,
 	Args: cobra.ArbitraryArgs,
 	RunE: func(cmd *cobra.Command, args []string) error {
 		for _, arg := range args {
-			b, err := gohex.DecodeString(arg)
+			var b []byte
+			var err error
+			if decodeKeyOptions.useBase64 {
+				b, err = base64.StdEncoding.DecodeString(arg)
+			} else {
+				b, err = gohex.DecodeString(arg)
+			}
 			if err != nil {
 				return err
 			}
@@ -1697,6 +1707,9 @@ func init() {
 	f.Var(&debugMergeLogsOpts.useColor, "color",
 		"force use of TTY escape codes to colorize the output")
 
+	f = debugDecodeKeyCmd.Flags()
+	f.BoolVar(&decodeKeyOptions.useBase64, "base64", false, "use base64 encoding for keys")
+
 	f = debugDecodeProtoCmd.Flags()
 	f.StringVar(&debugDecodeProtoName, "schema", "cockroach.sql.sqlbase.Descriptor",
 		"fully qualified name of the proto to decode")