deploy_helper - Manages some of the steps common in deploying projects.¶

# General explanation, starting with an example folder structure for a project:

# root:
#     releases:
#         - 20140415234508
#         - 20140415235146
#         - 20140416082818
#
#     shared:
#         - sessions
#         - uploads
#
#     current: releases/20140416082818


# The 'releases' folder holds all the available releases. A release is a complete build of the application being
# deployed. This can be a clone of a repository for example, or a sync of a local folder on your filesystem.
# Having timestamped folders is one way of having distinct releases, but you could choose your own strategy like
# git tags or commit hashes.
#
# During a deploy, a new folder should be created in the releases folder and any build steps required should be
# performed. Once the new build is ready, the deploy procedure is 'finalized' by replacing the 'current' symlink
# with a link to this build.
#
# The 'shared' folder holds any resource that is shared between releases. Examples of this are web-server
# session files, or files uploaded by users of your application. It's quite common to have symlinks from a release
# folder pointing to a shared/subfolder, and creating these links would be automated as part of the build steps.
#
# The 'current' symlink points to one of the releases. Probably the latest one, unless a deploy is in progress.
# The web-server's root for the project will go through this symlink, so the 'downtime' when switching to a new
# release is reduced to the time it takes to switch the link.
#
# To distinguish between successful builds and unfinished ones, a file can be placed in the folder of the release
# that is currently in progress. The existence of this file will mark it as unfinished, and allow an automated
# procedure to remove it during cleanup.


# Typical usage
- name: Initialize the deploy root and gather facts
  deploy_helper:
    path: /path/to/root
- name: Clone the project to the new release folder
  git:
    repo: git://foosball.example.org/path/to/repo.git
    dest: '{{ deploy_helper.new_release_path }}'
    version: v1.1.1
- name: Add an unfinished file, to allow cleanup on successful finalize
  file:
    path: '{{ deploy_helper.new_release_path }}/{{ deploy_helper.unfinished_filename }}'
    state: touch
- name: Perform some build steps, like running your dependency manager for example
  composer:
    command: install
    working_dir: '{{ deploy_helper.new_release_path }}'
- name: Create some folders in the shared folder
  file:
    path: '{{ deploy_helper.shared_path }}/{{ item }}'
    state: directory
  with_items:
    - sessions
    - uploads
- name: Add symlinks from the new release to the shared folder
  file:
    path: '{{ deploy_helper.new_release_path }}/{{ item.path }}'
    src: '{{ deploy_helper.shared_path }}/{{ item.src }}'
    state: link
  with_items:
      - path: app/sessions
        src: sessions
      - path: web/uploads
        src: uploads
- name: Finalize the deploy, removing the unfinished file and switching the symlink
  deploy_helper:
    path: /path/to/root
    release: '{{ deploy_helper.new_release }}'
    state: finalize

# Retrieving facts before running a deploy
- name: Run 'state=query' to gather facts without changing anything
  deploy_helper:
    path: /path/to/root
    state: query
# Remember to set the 'release' parameter when you actually call 'state=present' later
- name: Initialize the deploy root
  deploy_helper:
    path: /path/to/root
    release: '{{ deploy_helper.new_release }}'
    state: present

# all paths can be absolute or relative (to the 'path' parameter)
- deploy_helper:
    path: /path/to/root
    releases_path: /var/www/project/releases
    shared_path: /var/www/shared
    current_path: /var/www/active

# Using your own naming strategy for releases (a version tag in this case):
- deploy_helper:
    path: /path/to/root
    release: v1.1.1
    state: present
- deploy_helper:
    path: /path/to/root
    release: '{{ deploy_helper.new_release }}'
    state: finalize

# Using a different unfinished_filename:
- deploy_helper:
    path: /path/to/root
    unfinished_filename: README.md
    release: '{{ deploy_helper.new_release }}'
    state: finalize

# Postponing the cleanup of older builds:
- deploy_helper:
    path: /path/to/root
    release: '{{ deploy_helper.new_release }}'
    state: finalize
    clean: False
- deploy_helper:
    path: /path/to/root
    state: clean
# Or running the cleanup ahead of the new deploy
- deploy_helper:
    path: /path/to/root
    state: clean
- deploy_helper:
    path: /path/to/root
    state: present

# Keeping more old releases:
- deploy_helper:
    path: /path/to/root
    release: '{{ deploy_helper.new_release }}'
    state: finalize
    keep_releases: 10
# Or, if you use 'clean=false' on finalize:
- deploy_helper:
    path: /path/to/root
    state: clean
    keep_releases: 10

# Removing the entire project root folder
- deploy_helper:
    path: /path/to/root
    state: absent

# Debugging the facts returned by the module
- deploy_helper:
    path: /path/to/root
- debug:
    var: deploy_helper