Scriptling Scriptling

scriptling.provision.package

Overview

scriptling.provision.package installs and removes system packages. It asks which of the packages are installed first and runs the package manager only when something needs doing, so a script that has already run once does not touch apt at all.

It finds the package manager itself: apt, dnf, yum, apk or Homebrew, in that order.

apt, dnf, yum and apk need root, which the library uses on its own through sudo; you don’t pass become=True. The scriptling CLI refuses it with --deny-become (see Running as Root). Homebrew always runs as the user.

The library is registered only where the subprocess library is.

Available Functions

Function Description
ensure(packages, update=False, manager=None) Install the packages not yet installed
absent(packages, manager=None) Remove the packages that are installed
installed(packages, manager=None) Whether every package is installed
manager() The package manager in use

Constants

Constant Description
package.CREATED Something was installed ("created")
package.UNCHANGED Everything was already installed ("unchanged")
package.REMOVED Something was removed ("removed")
package.ABSENT Nothing was installed to remove ("absent")

Functions

ensure(packages, update=False, manager=None)

Installs those of packages that are not installed.

A new machine (a fresh container, say) often has no package lists, and an old one may have stale lists. Either way the install fails, so ensure() then refreshes the lists and tries once more. apt also waits up to five minutes for another apt to finish (unattended-upgrades on a new machine, for example) rather than failing at its lock.

Parameters:

  • packages (str or list): A package name, or a list of them.
  • update (bool, optional): Refresh the package lists before installing. Default: False.
  • manager (str, optional): "apt", "dnf", "yum", "apk" or "brew". Default: the first of these found.

Returns: str: package.CREATED or package.UNCHANGED.

Raises: Error when the package manager fails, with the command and the last lines it wrote. PermissionError, which the script cannot catch, where root is needed and running as root is not allowed.

import scriptling.provision.package as package

if package.ensure(["nginx", "curl"]) == package.CREATED:
    print("installed")

absent(packages, manager=None)

Removes those of packages that are installed.

Returns: str: package.REMOVED or package.ABSENT.

import scriptling.provision.package as package

package.absent("telnet")

installed(packages, manager=None)

Returns: bool: True when every one of packages is installed. Asking needs no root.

manager()

Returns: str or None: "apt", "dnf", "yum", "apk" or "brew"; None when there is none.

See Also