Command line interface

Fastack is very much inspired from flask which also provides command line like flask command called fastack.

Aims to make it easier for you to manage apps and also sometimes we need something, like add dummy data, run server, show app details, etc.

And I think this should be a "mandatory feature" for modern frameworks :D

Create command

We use the typer, to create the command line. As we know, the creator of typer is also the creator of FastAPI too xD.

Let's make our first command:

app/commands/user.py

from typer import Typer, echo

cli = Typer(name="user", help="user command")

@cli.command()
def create():
    """
    Create new user
    """
    email = input("Email: ")
    echo(f"User email: {email}")

Then add it to the app via the COMMANDS configuration:

COMMANDS = [
    "app.commands.user.cli",
]

In the above example we will import the cli variable in app/commands/user.py and then put it into the fastack command.

Now we check the user command in fastack:

$ fastack user --help
Usage: fastack user [OPTIONS] COMMAND [ARGS]...

  user command

Options:
  --help  Show this message and exit.

Commands:
  create

If you run fastack user create it will ask you to enter email and print it in the console.

$ fastack user create
Email: hello@world.id
User email: hello@world.id

In the above example, we created a sub-command called user and now we are going to create only command instead of sub-command.

app/commands/user.py

from typer import echo

def create():
    """
    Create new user
    """
    email = input("Email: ")
    echo(f"User email: {email}")

Then update the COMMANDS configuration to:

COMMANDS = [
    "app.commands.user.create",
]

Let's see, if the create command is in the fastack command:

fastack --help
Usage: fastack [OPTIONS] COMMAND [ARGS]...

  fastack is an intuitive framework based on FastAPI.

Options:
  -v, --version                   Show version number and exit
  --install-completion [bash|zsh|fish|powershell|pwsh]
                                  Install completion for the specified shell.
  --show-completion [bash|zsh|fish|powershell|pwsh]
                                  Show completion for the specified shell, to
                                  copy it or customize the installation.
  --help                          Show this message and exit.

Commands:
  create     Create new user
  new        Create project.
  routes     List all routes.
  runserver  Run app with uvicorn.

      fastack (c) 2021 - 2022 aprila hijriyan.

As you can see, the create command is available in fastack and is ready to use:

$ fastack create
Email: hello@mars.id
User email: hello@mars.id

For more information, you can visit the typer documentation directly at https://typer.tiangolo.com/

Using application context on commands

To enable the application context, fastack provides a decorator called enable_context which allows you to fully access the app instance object without importing them. For example:

from typer import echo
from fastack.decorators import enable_context
from fastack.globals import current_app

@enable_context()
def create():
    """
    Create new user
    """
    can_create_user = current_app.get_setting("CAN_CREATE_USER", False)
    if can_create_user:
        email = input("Email: ")
        echo(f"User email: {email}")
    else:
        echo("You can't create user")

what the enable_context decorator does here is:

1. Pushes the app instance object to the local context, which allows you to access it from fastack.globals.current_app.
2. Triggers startup and shutdown events in the application and allows you to access all plugins that are initialized at startup event via fastack.globals.state.

Adding a global command using the entry point

We also support adding commands from global to the fastack CLI. This feature is also inspired by flask.

You can add global commands using the fastack.commands entry point group. First you have to create a python module or package, then configure the entry point as below:

setup.pypyproject.toml (python-poetry)

setup(
  ...,
  entry_points={
      'fastack.commands': [
          'awesome = awesome.cli:awesome_command',
      ],
  },
)

[tool.poetry.plugins."fastack.commands"]
awesome = "awesome.cli:awesome_command"

For more information about entry points, please visit the link below:

• https://stackoverflow.com/questions/774824/explain-python-entry-points
• https://setuptools.pypa.io/en/latest/pkg_resources.html#entry-points

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Last update: January 17, 2022 13:26:42