Quickstart

In this section, you will learn how to install install_process, and how to define the installation process of a basic example environment.

This example will go through the main concepts of install_process:

  • how to define install-steps

  • how to group install-steps in an installation process

  • how to launch you new installation process, in order to install & uninstall the basic example environment

../_images/quickstart_full_install.png

Install ìnstall_process

pip install install_process

Define your first installation process

The Scenario

Let’s suppose you need to set up your environment, and for that you need to:

  1. install an SQL database

  2. configure the database

  3. unzip a file at a certain location

You could use install_process to define:
  • The database installation & uninstallation process

    • the database install & uninstall

    • the database configuration & revert to default config

  • Unzip the file & remove the file

Your Fist install-step

In order to define our scenario using install_process, you need to define install-steps. From our example:

  1. install an SQL database → could be defined as an install step

  2. configure the database → could be defined as an install step

  3. unzip a file at a certain location → could be defined as an install step

Install-steps are the basic element of install_process. In an install step, you define an installation sequence, and an uninstallation sequence. To show what an install-step looks like in code, this is our “install an SQL database” step:

from install_process import InstallStep


# The database installation & uninstallation process
class InstallMyDatabase(InstallStep):
  def install(self) -> None:
    """Install my database."""
    # [do what's required to install your database here]

    # you can display messages to users if you want
    self.display.msg('Database install step')
    # you can call shell commands such as ``self.shell('install mysql')``

  def uninstall(self) -> None:
    """Uninstall my database."""
    # [do what's required to uninstall your database here]

When defining an install step, you need to take care of how to install the step, and how to uninstall it, by implementing the install and uninstall methods.

Do note that the install and uninstall methods docstring (“””Install my database.””” and “””Uninstall my database.”””) are important, as they will be displayed when your entire install process is launched.

Other install-steps

The 2 other install-steps for “configure the database” & “unzip a file”:

# The database configuration & revert to default process
class ConfigureMyDatabase(InstallStep):
  def install(self) -> None:
    """Configure my database."""
    # do what's required to configure your database here

  def uninstall(self) -> None:
    """Revert my database configuration to default."""
    # do what's required to revert configuration here

# Unzip the file & remove the file
class UnzipMyFile(InstallStep):
  def install(self) -> None:
    """Unzip my file."""
    # unzip your file where required here

  def uninstall(self) -> None:
    """Remove my file."""
    # remove your file here

Group of install-steps

Since the steps InstallMyDatabase and ConfigureMyDatabase both share a role in the Database setup, you may optionally want to group them together.

# Let's regroup database-install & database-config under a same step (optional)
class Database(InstallSteps):
  """My Database setup"""
  steps = [
    InstallMyDatabase(),
    ConfigureMyDatabase(),
  ]

InstallSteps allow you to define a list of steps. Install steps will be installed in the order they are defined (an uninstalled in the reverse order).

Do note that the class docstring (“””My Database setup”””) is important, as it will be displayed when your entire install process is launched.

Define Your Installation Process

Now we have everything we need to create our installation process:

# Everything put together
class SetupMyEnvironment(InstallProcess):
  """MY INSTALLATION PROCESS"""
  steps = [
    Database(),
    UnzipMyFile(),
  ]

InstallProcess works just like InstallSteps, and allows you to define a list of steps. Install steps will be installed in the order they are defined (an uninstalled in the reverse order).

We are now ready to launch out installation. In order to do so, ìnstall_process provides a command line helper function:

if __name__ == '__main__':
  setup_install(SetupMyEnvironment)

(You can do more with installation steps, such as define installation conditions, parallel step execution, add specifics before starting / after completing the whole installation process. Check the doc on Install Steps).

Recap: the Entire Install File

Here’s a recap of what our environment setup code could look like, all in a my_environment_setup.py file:

# file: my_environment_setup.py

from install_process import InstallStep, InstallSteps, InstallProcess, setup_install

# The database installation & uninstallation process
class InstallMyDatabase(InstallStep):
  def install(self) -> None:
    """Install my database."""
    # do what's required to install your database here

  def uninstall(self) -> None:
    """Uninstall my database."""
    # do what's required to uninstall your database here

# The database configuration & revert to default process
class ConfigureMyDatabase(InstallStep):
  def install(self) -> None:
    """Configure my database."""
    # do what's required to configure your database here

  def uninstall(self) -> None:
    """Revert my database configuration to default."""
    # do what's required to revert configuration here

# Let's regroup database-install & database-config under a same step (optional)
class Database(InstallSteps):
  """My Database setup"""
  steps = [
    InstallMyDatabase(),
    ConfigureMyDatabase(),
  ]

# Unzip the file & remove the file
class UnzipMyFile(InstallStep):
  def install(self) -> None:
    """Unzip my file."""
    # unzip your file where required here

  def uninstall(self) -> None:
    """Remove my file."""
    # remove your file here


class SetupMyEnvironment(InstallProcess):  # Put everything together
  """MY INSTALLATION PROCESS"""  # This docstring will actually be displayed
  steps = [
    Database(),  # Database install & config
    UnzipMyFile(),  # File unzipping
  ]


if __name__ == '__main__':
  setup_install(SetupMyEnvironment)

(You can do more with installation steps, such as define installation conditions, parallel step execution, add specifics before starting / after completing the whole installation process. Check the doc on Install Steps).

Launch Install, Uninstall, Reinstall

Now you can install your entire environment, when executing the file:

python -m my_environment_setup
../_images/quickstart_full_install.png

If you need to uninstall your environment:

python -m my_environment_setup -i uninstall
../_images/quickstart_full_uninstall.png

(You can do more with the command line, such as installing/uninstalling only specific steps, activate verbose mode. Check the doc on Install Process Command Line).