# Build CLI App in Python with Click and Publish to PyPI

## Background

Of course, you all are aware of CLI(Command Line Interface) tools, because you might use any OS like Linux-based, Mac or Windows, you have used these tools in your life. These are Git CLI, language interpreters and runtimes(Python, Node, Ruby, Java, Go etc), system commands and network utilities(reboot, restart, ping etc), editors like nano, vim and there many other tools and command line software that we use nowadays which are minimalist to fulfil our needs and save time. In this tutorial, I'll explain how to implement a CLI app that gives answers to your input about me based on CLI inputs. Let's dive in.

## Setup

> If you don't want to set up and go with development/install/publish flow and directly want to try CLI, then you can clone or direct install the package.
> 
> [GitHub Source](https://github.com/piyush-multiplexer/click-piyush)

First, we'll be using Python 3 for this project. let's install basic dependencies.

* Install PIP, python package manager, used to install Python packages.
    
    ```bash
    sudo apt install python3-pip
    ```
    
* Install a virtual environment for this project, which isolates python packages.
    
    ```bash
    sudo apt-get install python3-virtualenv
    ```
    
* Make the project directory(**click-piyush**), set up *virtualenv* and activate. Then install [*click*](https://github.com/pallets/click) with pip, the library to make CLI apps.
    
    ```bash
    mkdir click-piyush
    cd click-piyush
    virtualenv venv
    . venv/bin/activate
    pip install click
    ```
    

## Let's Code

Let's create a python file named *clickpiyush.py* where we'll write the below code.

```python
import click

@click.command()
def age():
    """Get Age"""
    click.echo("I'm 2X years older, shouldn't be matter.")

if __name__ == '__main__':
    age()
```

Here we are importing the package **click** that is used to make the CLI app.  
Then we are adding one command to get the age and method for that command, which prints the age. Then call the method when the script is executed.

```bash
$ python test.py 
I'm 2X years older, shouldn't be matter.
```

Here, as you can see, you are not seeing any feeling like the CLI app but a simple script is running and printing some stuff, just like a normal python program does.  
Now you can register for options and arguments(next section) or make command groups for adding multiple commands or nesting of commands. Let's do that.

```python
import click

@click.group()
def cli():
    pass

@click.command()
def age():
    """Get Age"""
    click.echo("I'm 2X years older, shouldn't be matter.")

cli.add_command(age)

if __name__ == '__main__':
    cli()
```

In this, we have made slight changes. We are adding multi-command using group functionality of click. inside that, we added one method which passes invocation as it's empty. Using that *cli()* method, we are registering the command using *add\_command* and passing an argument of the commanding method(*age*). Now you can see the output below. As you can see click auto-generate beautiful Usage guide, options and help pages.

```bash
$ python test.py 
Usage: test.py [OPTIONS] COMMAND [ARGS]...

Options:
  --help  Show this message and exit.

Commands:
  age  Get Age
```

Now we'll add different types of commands and functionality to our CLI app.

```python
@click.command()
@click.option('--name', prompt='Identify youself by name')
def greet(name):
    """Describe this tool with colors to You."""
    click.secho(f"Hello {name}", bold=True, bg='green', fg='black')
    click.secho(
        "This is Command Line Interface which gives information of maker named Piyush.", bg='blue', fg='white')

cli.add_command(greet)
```

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1677230055299/27a08242-81e1-4adc-8509-9bef069f8fcd.png align="center")

In this **greet** command, we are asking for ***\--name*** option using the runtime prompt, you can configure it as you want. which is stored in the **name** variable for further access to the method. Inside that, we are printing two lines with different background colours and font colours in CLI using [`click.secho()`](https://click.palletsprojects.com/en/8.1.x/api/#click.secho). It combines echo and style functionality of click in one method and styles of the font as bold.

Let's add another command.

```python
@click.command()
@click.option('--desc', default=False, show_default=True, help='Show detailed Info.')
def bio(desc):
    """Basic Bio"""
    if desc:
        click.echo("Hey, this is piyush here, thanks for your interest.\nTo know more about me please run this CLI and different commands.\nThank You!")
    else:
        click.echo("This is me, and describing self.")

cli.add_command(bio)
```

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1677230775190/1a8b67a0-05ea-4d1b-9415-0c0b41f0dccb.png align="center")

In the **bio** command, the user can get information about me, but basic if not input is passed. To get detailed info `--desc true` flag must be passed. This argument can be configured with the *@click.option* method. In which you can describe the default value, enabling the default value in the help doc and help text.

### Full Code and Output

Here is the full code of my package script *clickpiyush.py* and the output is below for your reference.

```python
import click
import time


@click.group()
def cli():
    pass


@click.command()
@click.option('--name', prompt='Identify youself by name')
def greet(name):
    """Describe this tool with colors to You."""
    click.secho(f"Hello {name}", bold=True, bg='green', fg='black')
    click.secho(
        "This is Command Line Interface which gives information of maker named Piyush.", bg='blue', fg='white')


@click.command()
@click.option('--desc', default=False, show_default=True, help='Show detailed Info.')
def bio(desc):
    """Basic Bio"""
    if desc:
        click.echo("Hey, this is piyush here, thanks for your interest.\nTo know more about me please run this CLI and different commands.\nThank You!")
    else:
        click.echo("This is me, and describing self.")


@click.command()
def age():
    """Get Age"""
    click.echo("I'm 2X years older, shouldn't be matter.")


@click.command()
def skills():
    """Get my dummy skills set with progress bar"""
    skill_set = ["JavaScript", "Python", "GraphQL", "C", "TypeScript", "VueJS",
                 "NuxtJS", "Socket Programming", "Machine Learning", "NodeJS", "Linux"]

    with click.progressbar(skill_set, label='Getting skills', length=len(skill_set)-1, show_eta=False, color='blue') as skill_list:
        for skill in skill_list:
            click.echo(f" {skill}")
            time.sleep(0.3)


@click.command()
def blog():
    """Get My blog URL"""
    blog_url = "https://blog.thesourcepedia.org/"
    click.echo(f"{blog_url}   Wanna visit [y/n]: ", nl=False)
    c = click.getchar()
    click.echo(c)
    if c == 'y':
        click.echo("Launching Piyush's Blog")
        click.launch(blog_url)


@click.command()
def portfolio():
    """Launch my Portfolio!"""
    click.launch("https://piyushgoyani.thesourcepedia.org/")


# @click.command()
# @click.Choice()
cli.add_command(greet)
cli.add_command(bio)
cli.add_command(age)
cli.add_command(skills)
cli.add_command(blog)
cli.add_command(portfolio)

if __name__ == '__main__':
    cli()
```

### Running CLI Locally

To run the and see output execute [clickpiyush.py](http://clickpiyush.py) file with no argument or option so it'll show help and all command as below.

```bash
python clickpiyush.py
Usage: clickpiyush.py [OPTIONS] COMMAND [ARGS]...

Options:
  --help  Show this message and exit.

Commands:
  age        Get Age
  bio        Basic Bio
  blog       Get My blog URL
  greet      Describe this tool with colors to You.
  portfolio  Launch my Portfolio!
  skills     Get my dummy skills set with progress bar
```

In this, we are launching a website in a browser based on the user input, showing a progress bar in skill command and more.  
[Source Repository](https://github.com/piyush-multiplexer/click-piyush)

## Prepare for Package

Let's create a ***setup.py*** file and paste the below configuration. This file contains the name of the package, version, inside modules, requirements, entry points and more configurable things.

```python
from setuptools import setup

setup(
    name='clickpiyush',
    version='1.0.1,
    py_modules=['clickpiyush'],
    install_requires=['Click', ],
    entry_points={
        'console_scripts': [
            'clickpiyush = clickpiyush:cli'
        ]
    }
)
```

### Install Local Package

We have created a setup file, now we can install our CLI app and run it just like a normal program, so don't need to invoke a python interpreter.

```bash
pip install --editable .
```

```plaintext
Obtaining file:///home/piyush/Documents/prs/click-piyush
Requirement already satisfied: Click in ./venv/lib/python3.8/site-packages (from clickpiyush==1.0.1) (8.1.3)
Installing collected packages: clickpiyush
  Running setup.py develop for clickpiyush
Successfully installed clickpiyush
```

As you can see ***clickpiyush*** package is installed successfully, now you can use it with the name of the CLI app.

```bash
clickpiyush
```

## Publish to PyPI

Till now whatever we make, run and install was on our system. Now we want to publish our package to PyPI(Python Package Index) so other users can download our CLI app and use it in their system.

```bash
python setup.py sdist
```

Once we run the above command, we have a new directory *dist/*, which contains our distribution or simply archived package.

```plaintext
running sdist
running egg_info
writing clickpiyush.egg-info/PKG-INFO
writing dependency_links to clickpiyush.egg-info/dependency_links.txt
writing entry points to clickpiyush.egg-info/entry_points.txt
writing requirements to clickpiyush.egg-info/requires.txt
writing top-level names to clickpiyush.egg-info/top_level.txt
reading manifest file 'clickpiyush.egg-info/SOURCES.txt'
adding license file 'LICENSE'
writing manifest file 'clickpiyush.egg-info/SOURCES.txt'
running check
creating clickpiyush-1.0.1
creating clickpiyush-1.0.1/clickpiyush.egg-info
copying files to clickpiyush-1.0.1...
copying LICENSE -> clickpiyush-1.0.1
copying README.md -> clickpiyush-1.0.1
copying clickpiyush.py -> clickpiyush-1.0.1
copying setup.cfg -> clickpiyush-1.0.1
copying setup.py -> clickpiyush-1.0.1
copying clickpiyush.egg-info/PKG-INFO -> clickpiyush-1.0.1/clickpiyush.egg-info
copying clickpiyush.egg-info/SOURCES.txt -> clickpiyush-1.0.1/clickpiyush.egg-info
copying clickpiyush.egg-info/dependency_links.txt -> clickpiyush-1.0.1/clickpiyush.egg-info
copying clickpiyush.egg-info/entry_points.txt -> clickpiyush-1.0.1/clickpiyush.egg-info
copying clickpiyush.egg-info/requires.txt -> clickpiyush-1.0.1/clickpiyush.egg-info
copying clickpiyush.egg-info/top_level.txt -> clickpiyush-1.0.1/clickpiyush.egg-info
Writing clickpiyush-1.0.1/setup.cfg
Creating tar archive
removing 'clickpiyush-1.0.1' (and everything under it)
```

Now let's install twine. It's a utility to publish python packages to PyPI and then upload generated distribution.

```plaintext
pip install twine
twine upload dist/*
```

After you run the command, you'll show that distribution is uploading to PyPI and asking for your credentials. Once you enter those, the package will be published successfully and listed in PyPI as this.

%[https://pypi.org/project/clickpiyush/] 

Now anyone can install this package by using the below command.

```bash
pip install clickpiyush

$ clickpiyush
Usage: clickpiyush [OPTIONS] COMMAND [ARGS]...

Options:
  --help  Show this message and exit.

Commands:
  age        Get Age
  bio        Basic Bio
  blog       Get My blog URL
  greet      Describe this tool with colors to You.
  portfolio  Launch my Portfolio!
  skills     Get my dummy skills set with progress bar
```

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