command/

README

How to add a new Command

Before making any changes, please consult the CLI style guide!

Package Layout

The urfave/cli package that forms the basis of Step CLI supports N-levels of command hierarchy. Each level of the hierarchy should exist within its own package if possible. For example, version and help exist inside their own packages inside the top-level command package.

Any package used by a command but does not contain explicit business logic directly related to the command should exist in the top-level of this repository. For example, the github.com/smallstep/cli/flags and go.step.sm/cli-utils/errs package are used by many different commands and contain functionality for defining flags and creating/manipulating errors.

Adding a Command

Once you figured out where to add the command inside the package hierarchy you must register the command. This way the command can be made available if desired inside the cmd/step/main.go.

An example of defining a command and registering it:

package validate

import (
  "github.com/urfave/cli"

  "github.com/smallstep/cli/command"
  "github.com/smallstep/cli/flags"
)

func init() {
  cmd := cli.Command{
    Name: "validate",
    Usage: "Returns whether or not the provided token is valid",
    Flags: []cli.Flag{
      flags.Token("The one-time token value to validate"),
    },
    Action: validate,
  }

  command.Register(validate)
}

Once this is done, you then must import the pkg inside cmd/step/main.go so the packages init method is run appropriately. This only needs to be done for top-level commands.

package main

import (
  "github.com/urfave/cli"

  _ "github.com/smallstep/cli/validate"
)

This will ensure that the smallstep/cli/validate package is initialized and thus registered with the smallstep/cli/command.

Usage, Flags, Errors, and Prompts

There are three packages which contain functionality to make writing commands easier:

• github.com/smallstep/cli/usage
• github.com/smallstep/cli/flags
• github.com/smallstep/cli/prompts
• go.step.sm/cli-utils/errs

The usage package is used to extend the default documentation provided by urfave/cli by enabling us to document arguments, whether they are optional or required, and ensuring they're printed out as a part of the step help or step <command> -h flow. If you need to add a different type of annotation to document an argument just add it to the usage.Argument struct!

When you add a flag, look into the preexisting ones inside the flags package. Could you use one of the preexisting flags in order to reduce duplication? If not, make sure to add a flag so it could be used in future!

The errs package contains functionality for defining and working with errors to ensure they are mutated properly into a urfave/cli.ExitError which ensures the process returns an appropriate exit code on termination. When you create an error, consider whether or not it's general and could be predefined inside the errs package. Errors that are specific to the command itself should exist only inside that commands respective package.

The prompts package is a small wrapper around the various different types of prompts used by the commands. If you need a new prompt, consider adding a new function to this package to tailor the prompt for the step cli. This way other commands can adopt the step aesthetic as new functionality is introduced.

Hiding a Command

Sometimes it's desirable to prevent a command from showing up in the help menu because it's been deprecated or it's not ready for users to leverage. This can be achieved by setting the Hidden property on the cli.Command struct to true.