add json output to Conclude command

Signed-off-by: Harshit Gangal <harshit@planetscale.com>

go/cmd/vtctldclient/command/transactions.go

@@ -58,6 +58,17 @@ var (
  }
 )
 
+type ConcludeTransactionOutput struct {
+ Dtid string `json:"dtid"`
+ Message string `json:"message"`
+ Error string `json:"error,omitempty"`
+}
+
+const (
+ concludeSuccess = "Successfully concluded the distributed transaction"
+ concludeFailure = "Failed to conclude the distributed transaction"
+)
+
 func commandGetUnresolvedTransactions(cmd *cobra.Command, args []string) error {
  cli.FinishedParsing(cmd)
 
@@ -74,7 +85,7 @@ func commandGetUnresolvedTransactions(cmd *cobra.Command, args []string) error {
  if err != nil {
  return err
  }
- fmt.Printf("%s\n", data)
+ fmt.Println(string(data))
  return nil
 }
 
@@ -94,17 +105,25 @@ func commandConcludeTransaction(cmd *cobra.Command, args []string) error {
  Shard: shard.Name,
  })
  }
+ output := ConcludeTransactionOutput{
+ Dtid: dtid,
+ Message: concludeSuccess,
+ }
+
  _, err = client.ConcludeTransaction(commandCtx,
  &vtctldatapb.ConcludeTransactionRequest{
  Dtid: dtid,
  Participants: participants,
  })
  if err != nil {
- return err
+ output.Message = concludeFailure
+ output.Error = err.Error()
  }
- fmt.Println("Successfully concluded the distributed transaction")
 
- return nil
+ data, _ := cli.MarshalJSON(output)
+ fmt.Println(string(data))
+
+ return err
 }
 
 func init() {