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06 - Loops

Learn how to iterate over lists and files to avoid repetition.

What You'll Learn

  • Iterating over lists with with_items
  • Iterating over files with with_filetree
  • Using the {{ item }} variable
  • Accessing file properties in loops

Quick Start

# Run list iteration example
mooncake run --config with-items.yml

# Run file tree iteration example
mooncake run --config with-filetree/config.yml

Examples Included

1. with-items.yml - List Iteration

Iterate over lists of items: 

- vars:
    packages:
      - neovim
      - ripgrep
      - fzf

- name: Install package
  shell: brew install {{ item }}
  with_items: "{{ packages }}"

What it does:

  • Defines lists in variables
  • Installs multiple packages
  • Creates directories for multiple users
  • Creates user-specific config files

2. with-filetree/ - File Tree Iteration

Iterate over files in a directory: 

- name: Copy dotfile
  shell: cp "{{ item.src }}" "/tmp/backup/{{ item.name }}"
  with_filetree: ./files

What it does:

  • Iterates over files in ./files/ directory
  • Copies dotfiles to backup location
  • Filters directories vs files
  • Displays file properties

Key Concepts

List Iteration (with_items)

- vars:
    users: [alice, bob, charlie]

- name: Create user directory
  file:
    path: "/home/{{ item }}"
    state: directory
  with_items: "{{ users }}"

This creates:

  • /home/alice
  • /home/bob
  • /home/charlie

File Tree Iteration (with_filetree)

- name: Process file
  shell: echo "Processing {{ item.name }}"
  with_filetree: ./dotfiles
  when: item.is_dir == false

Available properties:

  • item.src - Full source path
  • item.name - File name
  • item.is_dir - Boolean, true if directory

Filtering in Loops

Skip directories: 

- name: Copy files only
  shell: cp "{{ item.src }}" "/tmp/{{ item.name }}"
  with_filetree: ./files
  when: item.is_dir == false

Real-World Use Cases

with_items:

  • Installing multiple packages
  • Creating multiple users/groups
  • Setting up multiple services
  • Deploying to multiple servers

with_filetree:

  • Managing dotfiles
  • Deploying configuration directories
  • Backing up files
  • Processing file collections

Testing

# List iteration
mooncake run --config with-items.yml

# Check created files
ls -la /tmp/users/

# File tree iteration
mooncake run --config with-filetree/config.yml

# Check backed up files
ls -la /tmp/dotfiles-backup/

Next Steps

→ Continue to 07-register to learn about capturing command output.