Dependencies

step completion

In configuration, each step can declare what it provides and what it requires.
The program resolves the graph automatically: a step will only run after all steps that provide its requires are completed.

info

By completion, I mean that all the step’s packages (if any) are installed and the check script (if needed) executes successfully.

check script is needed to verify completion only if step has script.
Without it, program cannot determine the completion state, so the step will not be marked as completed in dry-run or interactive mode.
pre_script doesn't require check because its main purpose to prepare environment for packages installation. If packages are installed, then it's reasonable to assume that pre_script was successful.

warning

An error occurs if multiple steps providing the same required artifact pass the OS and when script filters.

provides

The provides field lists artifacts or capabilities that a step produces. Other steps can depend on these artifacts by using requires.

Example:

- id: install_postgres
  provides:
    - postgres_installed

- id: setup_database
  requires:
    - postgres_installed

Here, setup_database depends on postgres_installed, which is produced by install_postgres. The program ensures install_postgres runs first.

Automatic inference

If a step has packages but no provides, the provides field is automatically set to the package names as declared in packages. Package-manager-specific names (see package aliases ) are resolved only for installation, not for provides.

Example 1: simple package

- id: install_postgres
  packages: ["postgresql"]

This is equivalent to:

- id: install_postgres
  packages: ["postgresql"]
  provides: ["postgresql"]

Example 2: package with aliases

# in pkg_aliases.yaml:
fd:
  apt: fd-find
  dnf: fd-find
  zypper: fd-find

# in config:
steps:
  - id: install_fd
    packages: ["fd"]

Here, provides is automatically set to ["fd"], regardless of the package manager.

requires

The requires field lists dependencies a step needs before it can run. These dependencies declare:

• Needed artifacts provided by other steps (provides)
• Conditional requirements based on OS (os)
• Conditional requirements based on when scripts

Basic example

- id: install_app
  requires:
    - postgres_installed

Example with OS-specific requirement

- id: install-nvim-linux-helpers
  os: "linux"
  packages: ["wl-clipboard"]
  provides: ["nvim-linux-helpers"]

- id: install_nvim
  packages: ["nvim"]
  requires:
    - id: nvim-linux-helpers
      os: linux

Step install_nvim will only require nvim-linux-helpers if the current OS matches Linux.

Example with when-script requirement

- id: setup-init-system
  requires:
    - id: setup-systemd
      when: "pidof systemd >/dev/null 2>&1"

Here, the dependency setup-systemd is only required if the when script succeeds - current init system is systemd.

Scope

The requires and provides fields have global visibility across all included YAML files.
When a parent configuration uses includes:

includes:
  - first.yaml
  - second.yaml

All steps in first.yaml, second.yaml, and the parent YAML are merged into a single dependency graph. This means a step in one YAML can safely require a step defined in another YAML.

Behavior in interactive mode

Interactive mode allows you to skip step dependencies or rerun already completed steps, giving more control over execution flow.