CLI commands and mmctl

As of 6.0, Mattermost CLI has been replaced by mmctl. mmctl is built to enable access to Mattermost server from the command line. The tool leverages the public API so that administrator and user tasks can be performed.

Since mmctl uses the public API, an authorization mechanism is required. Which means the access rights are managed on the server side. There is a pre-run check to read credentials and use it in the client. In addition to authentication via credentials, mmctl can communicate to a local server without any authentication. This must be enabled via server configuration and both mmctl and mattermost/server needs to be running in the same machine.

In addition to provide more functionality towards testing and development, db subcommand has been added Mattermost server binary.

The CLI interface is written using Cobra, a powerful and modern CLI creation library. If you have never used Cobra before, it is well documented in its GitHub Repository.

The source code used to build our CLI interface is written in the commands directory of the mmctl repository.

Each “command” of the CLI is stored in a different file of the commands directory. Within each file, you can find multiple “subcommands”.

Add a new subcommand 

If you want to add a new subcommand in an existing mattermost command, first find the relevant file. For example, if you want to add a show command to the channel command, go to commands/channel.go and add your subcommand there.

To add the subcommand, start by creating a new Command instance, for example:

var ChannelShowCmd = &cobra.Command{
    Use:   "show",
    Short: "Show channel info",
    Long:  "Show channel information, including the name, header, purpose and the number of members.",
    Example: "  channel show --team myteam --channel mychannel"
    RunE: showChannelCmdF,
}

Then implement the subcommand function, in this example showChannelCmdF.

func showChannelCmdF(c client.Client, cmd *cobra.Command, args []string) error {
    // Your code implementing the command itself
    newChannel, _, err := c.ShowChannel(channel)
	if err != nil {
		return err
	}

    return nil
}

Now, you set the flags of your subcommand and register it in the command. In our case we register our new ChannelShowCmd flag in ChannelCmd.

func init() {
    ...

    ChannelShowCmd.Flags().String("team", "", "Team name or ID")
    ChannelShowCmd.Flags().String("channel", "", "Channel name or ID")
    ...
    ChannelCmd.AddCommand(
        ...
        ChannelShowCmd,
    )
    ...
}

Finally, implement unit tests in commands/channel_test.go and end-to-end tests to commands/channel_e2e_test.go`.

Add a new command 

If you want to add a new command to mmctl, first create a file for the command. For example, if you want to add a new emoji command to manage emojis in Mattermost from the CLI, create commands/emoji.go and add your command and your subcommands there.

A command is exactly the same as a subcommand, so you can follow the same steps of the previous section. However, you must also register the new command in the “Root” command as follows:

var EmojiCmd = &cobra.Command{
    Use:   "emoji",
    Short: "Emoji management",
    Long:  "Lists, creates and deletes custom emoji",
}
func init() {
    ...
    RootCmd.AddCommand(EmojiCmd)
    ...
}

Usually, you would then add several subcommands to perform various tasks.

Submit your pull request 

Please submit a pull request against the mattermost/mmctl repository by following these instructions.