cosmos-sdk/x/params/client/cli/tx.go

package cli

import (
	"strings"

	"github.com/spf13/cobra"

	"github.com/cosmos/cosmos-sdk/client/context"
	"github.com/cosmos/cosmos-sdk/client/utils"
	"github.com/cosmos/cosmos-sdk/codec"
	sdk "github.com/cosmos/cosmos-sdk/types"
	authtxb "github.com/cosmos/cosmos-sdk/x/auth/client/txbuilder"
	"github.com/cosmos/cosmos-sdk/x/gov"
	"github.com/cosmos/cosmos-sdk/x/params"
	paramscutils "github.com/cosmos/cosmos-sdk/x/params/client/utils"
)

// GetCmdSubmitProposal implements a command handler for submitting a parameter
// change proposal transaction.
func GetCmdSubmitProposal(cdc *codec.Codec) *cobra.Command {
	cmd := &cobra.Command{
		Use:   "param-change [proposal-file]",
		Args:  cobra.ExactArgs(1),
		Short: "Submit a parameter change proposal",
		Long: strings.TrimSpace(`
Submit a parameter proposal along with an initial deposit. The proposal details
must be supplied via a JSON file.

IMPORTANT: Currently parameter changes are evaluated but not validated, so it is
very important that any "value" change is valid (ie. correct type and within bounds)
for its respective parameter, eg. "MaxValidators" should be an integer and not a decimal.

Proper vetting of a parameter change proposal should prevent this from happening
(no deposits should occur during the governance process), but it should be noted
regardless. 

Example:
$ gaiacli tx gov submit-proposal param-change <path/to/proposal.json> --from=<key_or_address>
where proposal.json contains:
{
  "title": "Staking Param Change",
  "description": "Update max validators",
  "changes": [
    {
      "subspace": "staking",
      "key": "MaxValidators",
      "value": "105"
    }
  ],
  "deposit": [
    {
      "denom": "stake",
      "amount": "10000"
    }
  ]
}
`),
		RunE: func(cmd *cobra.Command, args []string) error {
			txBldr := authtxb.NewTxBuilderFromCLI().WithTxEncoder(utils.GetTxEncoder(cdc))
			cliCtx := context.NewCLIContext().
				WithCodec(cdc).
				WithAccountDecoder(cdc)

			proposal, err := paramscutils.ParseParamChangeProposalJSON(cdc, args[0])
			if err != nil {
				return err
			}

			from := cliCtx.GetFromAddress()
			content := params.NewParameterChangeProposal(proposal.Title, proposal.Description, proposal.Changes)

			msg := gov.NewMsgSubmitProposal(content, proposal.Deposit, from)
			if err := msg.ValidateBasic(); err != nil {
				return err
			}

			return utils.GenerateOrBroadcastMsgs(cliCtx, txBldr, []sdk.Msg{msg}, false)
		},
	}

	return cmd
}