Install packages declaratively

chezmoi uses a declarative approach for the contents of dotfiles, but package installation requires running imperative commands. However, you can simulate declarative package installation with a combination of a .chezmoidata file and a run_onchange_ script.

The following example uses homebrew on macOS, but should be adaptable to other operating systems and package managers.

First, create .chezmoidata/packages.yaml declaring the packages that you want installed, for example:

~/.local/share/chezmoi/.chezmoidata/packages.yaml

packages:
  darwin:
    brews:
    - 'git'
    casks:
    - 'google-chrome'

Second, create a run_onchange_darwin-install-packages.sh.tmpl script that uses the package manager to install those packages, for example:

~/.local/share/chezmoi/run_onchange_darwin-install-packages.sh.tmpl

{{ if eq .chezmoi.os "darwin" -}}
#!/bin/bash

brew bundle --no-lock --file=/dev/stdin <<EOF
{{ range .packages.darwin.brews -}}
brew {{ . | quote }}
{{ end -}}
{{ range .packages.darwin.casks -}}
cask {{ . | quote }}
{{ end -}}
EOF
{{ end -}}

Now, when you run chezmoi apply, chezmoi will execute the install-packages.sh script with when the list of packages defined in .chezmoidata/packages.yaml changes.