cleo 0.6.3

Cleo allows you to create beautiful and testable command-line interfaces.

Create beautiful and testable command-line interfaces.

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Usage

To make a command that greets you from the command line, create greet_command.py and add the following to it:

from cleo import Command


class GreetCommand(Command):
    """
    Greets someone

    demo:greet
        {name? : Who do you want to greet?}
        {--y|yell : If set, the task will yell in uppercase letters}
    """

    def handle(self):
        name = self.argument('name')

        if name:
            text = 'Hello %s' % name
        else:
            text = 'Hello'

        if self.option('yell'):
            text = text.upper()

        self.line(text)

You also need to create the file to run at the command line which creates an Application and adds commands to it:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from greet_command import GreetCommand
from cleo import Application

application = Application()
application.add(GreetCommand())

if __name__ == '__main__':
    application.run()

Test the new command by running the following

$ python application.py demo:greet John

This will print the following to the command line:

Hello John

You can also use the --yell option to make everything uppercase:

$ python application.py demo:greet John --yell

This prints:

HELLO JOHN

As you may have already seen, Cleo uses the command docstring to determine the command definition. The docstring must be in the following form :

"""
Command description

Command signature
"""

The signature being in the following form:

"""
command:name {argument : Argument description} {--option : Option description}
"""

The signature can span multiple lines.

"""
command:name
    {argument : Argument description}
    {--option : Option description}
"""

Coloring the Output

Whenever you output text, you can surround the text with tags to color its output. For example:

# green text
self.line('<info>foo</info>')

# yellow text
self.line('<comment>foo</comment>')

# black text on a cyan background
self.line('<question>foo</question>')

# white text on a red background
self.line('<error>foo</error>')

The closing tag can be replaced by </>, which revokes all formatting options established by the last opened tag.

You can also use the corresponding methods:

self.info('foo')
self.comment('foo')
self.question('foo')
self.error('foo')

It is possible to define your own styles using the set_style() method:

self.set_style('fire', fg='red', bg='yellow', options=['bold', 'blink'])
self.line('<fire>foo</fire>')

Available foreground and background colors are: black, red, green, yellow, blue, magenta, cyan and white.

And available options are: bold, underscore, blink, reverse and conceal.

You can also set these colors and options inside the tagname:

# green text
self.line('<fg=green>foo</>')

# black text on a cyan background
self.line('<fg=black;bg=cyan>foo</>')

# bold text on a yellow background
self.line('<bg=yellow;options=bold>foo</>')

Verbosity Levels

Cleo has five verbosity levels. These are defined in the Output class:

Mode	Meaning	Console option
Output.VERBOSITY_QUIET	Do not output any messages	-q or --quiet
Output.VERBOSITY_NORMAL	The default verbosity level	(none)
Output.VERBOSITY_VERBOSE	Increased verbosity of messages	-v
Output.VERBOSITY_VERY_VERBOSE	Informative non essential messages	-vv
Output.VERBOSITY_DEBUG	Debug messages	-vvv

It is possible to print a message in a command for only a specific verbosity level. For example:

if Output.VERBOSITY_VERBOSE <= self.output.get_verbosity():
    self.line(...)

There are also more semantic methods you can use to test for each of the verbosity levels:

if self.output.is_quiet():
    # ...

if self.output.is_verbose():
    # ...

When the quiet level is used, all output is suppressed as the default Output.write() method returns without actually printing.

Using Arguments

The most interesting part of the commands are the arguments and options that you can make available. Arguments are the strings - separated by spaces - that come after the command name itself. They are ordered, and can be optional or required. For example, add an optional last_name argument to the command and make the name argument required:

class GreetCommand(Command):
    """
    Greets someone

    demo:greet
        {name : Who do you want to greet?}
        {last_name? : Your last name?}
        {--y|yell : If set, the task will yell in uppercase letters}
    """

You now have access to a last_name argument in your command:

last_name = self.argument('last_name')
if last_name:
    text += ' %s' % last_name

The command can now be used in either of the following ways:

$ python application.py demo:greet John
$ python application.py demo:greet John Doe

It is also possible to let an argument take a list of values (imagine you want to greet all your friends). For this it must be specified at the end of the argument list:

class GreetCommand(Command):
    """
    Greets someone

    demo:greet
        {names* : Who do you want to greet?}
        {--y|yell : If set, the task will yell in uppercase letters}
    """

To use this, just specify as many names as you want:

$ python application.py demo:greet John Jane

You can access the names argument as a list:

names = self.argument('names')
if names:
    text += ' %s' % ', '.join(names)

There are 3 argument variants you can use:

Mode	Notation	Value
InputArgument.REQUIRED	none (just write the argument name)	The argument is required
InputArgument.OPTIONAL	argument?	The argument is optional and therefore can be omitted
InputArgument.IS_LIST	argument*	The argument can contain an indefinite number of arguments and must be used at the end of the argument list

You can combine IS_LIST with REQUIRED and OPTIONAL like this:

class GreetCommand(Command):
    """
    Greets someone

    demo:greet
        {names?* : Who do you want to greet?}
        {--y|yell : If set, the task will yell in uppercase letters}
    """

If you want to set a default value, you can it like so:

argument=default

The argument will then be considered optional.

Using Options

Unlike arguments, options are not ordered (meaning you can specify them in any order) and are specified with two dashes (e.g. --yell - you can also declare a one-letter shortcut that you can call with a single dash like -y). Options are always optional, and can be setup to accept a value (e.g. --dir=src) or simply as a boolean flag without a value (e.g. --yell).

Tip

It is also possible to make an option optionally accept a value (so that --yell or --yell=loud work). Options can also be configured to accept a list of values.

For example, add a new option to the command that can be used to specify how many times in a row the message should be printed:

class GreetCommand(Command):
    """
    Greets someone

    demo:greet
        {name? : Who do you want to greet?}
        {--y|yell : If set, the task will yell in uppercase letters}
        {--iterations=1 : How many times should the message be printed?}
    """

Next, use this in the command to print the message multiple times:

for _ in range(0, self.option('iterations')):
    self.line(text)

Now, when you run the task, you can optionally specify a --iterations flag:

$ python application.py demo:greet John
$ python application.py demo:greet John --iterations=5

The first example will only print once, since iterations is empty and defaults to 1. The second example will print five times.

Recall that options don’t care about their order. So, either of the following will work:

$ python application.py demo:greet John --iterations=5 --yell
$ python application.py demo:greet John --yell --iterations=5

There are 4 option variants you can use:

Option	Notation	Value
InputOption.VALUE_IS_LIST	--option=*	This option accepts multiple values (e.g. --dir=/foo --dir=/bar)
InputOption.VALUE_NONE	--option	Do not accept input for this option (e.g. --yell)
InputOption.VALUE_REQUIRED	--option=	This value is required (e.g. --iterations=5), the option itself is still optional
InputOption.VALUE_OPTIONAL	--option=?	This option may or may not have a value (e.g. --yell or --yell=loud)

You can combine VALUE_IS_LIST with VALUE_REQUIRED or VALUE_OPTIONAL like this:

class GreetCommand(Command):
    """
    Greets someone

    demo:greet
        {name? : Who do you want to greet?}
        {--y|yell : If set, the task will yell in uppercase letters}
        {--iterations=?*1 : How many times should the message be printed?}
    """

Testing Commands

Cleo provides several tools to help you test your commands. The most useful one is the CommandTester class. It uses special input and output classes to ease testing without a real console:

from unittest import TestCase
from cleo import Application, CommandTester

class GreetCommandTest(TestCase):

    def test_execute(self):
        application = Application()
        application.add(GreetCommand())

        command = application.find('demo:greet')
        command_tester = CommandTester(command)
        command_tester.execute([('command', command.get_name())])

        self.assertRegex('...', command_tester.get_display())

        # ...

The CommandTester.get_display() method returns what would have been displayed during a normal call from the console.

You can test sending arguments and options to the command by passing them as an list of tuples to the CommandTester.execute() method:

from unittest import TestCase
from cleo import Application, CommandTester

class GreetCommandTest(TestCase):

    def test_name_is_output(self):
        application = Application()
        application.add(GreetCommand())

        commmand = application.find('demo:greet')
        command_tester = CommandTester(command)
        command_tester.execute([
            ('command', command.get_name()),
            ('name', 'John')
        ])

        self.assertRegex('John', command_tester.get_display())

You can also test a whole console application by using the ApplicationTester class.

Calling an existing Command

If a command depends on another one being run before it, instead of asking the user to remember the order of execution, you can call it directly yourself. This is also useful if you want to create a “meta” command that just runs a bunch of other commands.

Calling a command from another one is straightforward:

def handle(self):
    return_code = self.call('demo:greet', [
        ('name', 'John'),
        ('--yell', True)
    ])

    # ...

If you want to suppress the output of the executed command, you can use the call_silent() method instead.

Autocompletion

Cleo supports automatic (tab) completion in bash and zsh.

To activate support for autocompletion, pass a complete keyword when initializing your application:

application = Application('My Application', '0.1', complete=True)

Now, register completion for your application by running one of the following in a terminal, replacing [program] with the command you use to run your application:

# BASH ~4.x, ZSH
source <([program] _completion --generate-hook)

# BASH ~3.x, ZSH
[program] _completion --generate-hook | source /dev/stdin

# BASH (any version)
eval $([program] _completion --generate-hook)

By default this registers completion for the absolute path to you application, which will work if the program is accessible on your PATH. You can specify a program name to complete for instead using the -p\--program option, which is required if you’re using an alias to run the program.

If you want the completion to apply automatically for all new shell sessions, add the command to your shell’s profile (eg. ~/.bash_profile or ~/.zshrc)

The type of shell (zsh/bash) is automatically detected using the SHELL environment variable at run time. In some circumstances, you may need to explicitly specify the shell type with the --shell-type option.