CODEWITHSUNDEEP
ansible
user2237076
user2237076

Reputation: 331

How to write conditional tasks in ansible

I've been trying to setup some ansible roles and playbooks.

The biggest challenge for me at the moment is the conditional running of tasks. My role has been evolving - primarily to get it to work. This is where I have got to, but it seems a bit awkward, and I was wondering if anyone could point me towards a better way.

I know the setup vars could go in /vars/main.yml, but any guidance from more experienced users would be great.

To put it bluntly, this has been a real slog to get ansible to install emacs-latest.

---
- name: Setup vars
  set_fact:
    emacs_requires_upgrade: false
    emacs_installed: false
    emacs_version: 0
    autoconf_upgrade_required: false

- name: Check for emacs
  command: which emacs
  changed_when: false
  failed_when: false
  register: emacs_installed

- name: Check emacs version
  shell: emacs --version | awk 'NR == 1' | cut -d " " -f 3
  register: emacs_version
  when: emacs_installed|success

- name: Emacs requires upgrade
  set_fact:
    emacs_requires_upgrade: true
  when:
    emacs_installed | failed or emacs_version | version_compare('24.5', '<')

# yum tools required to build emacs
- name: Ensure build tools are present
  yum: pkg={{ item }} state=latest
  with_items:
    - gcc
    - autoconf
    - automake
    - texinfo
    - ncurses
    - ncurses-devel
  when: emacs_requires_upgrade

# need to establish if autoconf needs to be upgraded (emacs requires 2.68 i think)
- name: stat autoconf
  stat: path=/usr/bin/autoconf
  register: autoconf
  when: emacs_requires_upgrade

- name: Check autoconf version
  shell: autoconf --version | awk 'NR == 1' | cut -d " " -f 4
  register: autoconf_version
  when: emacs_requires_upgrade and autoconf.stat.exists

- name: Autoconf version
  debug:
    var: "{{ autoconf_version.stdout }}"
  when: emacs_requires_upgrade and autoconf.stat.exists

- name: Autoconf requires upgrade
  set_fact:
    autoconf_upgrade_required: true
  when:
    emacs_requires_upgrade and
    {{ autoconf_version.stdout }} | version_compare('2.68','<')
- name: Move old autoconf
  shell: mv /usr/bin/autoconf /usr/bin/autoconf.old
  when:
    emacs_requires_upgrade and
    autoconf.stat.exists and
    autoconf_upgrade_required

- name: Check for autoconf previous download
  stat: path=/usr/local/share/autoconf-2.69
  register: autoconf_src
  when:
    emacs_requires_upgrade and
    autoconf_upgrade_required

- name: Install latest autoconf from source
  unarchive: src=http://ftp.gnu.org/gnu/autoconf/autoconf-2.69.tar.gz dest=/usr/local/share copy=no
  when:
    emacs_requires_upgrade and
    autoconf_upgrade_required

- name: Build Autoconf 2.69
  shell: "{{ item }}"
  args:
    chdir: "/usr/local/share/autoconf-2.69"
  with_items:
    - ./configure
    - make
    - make install
    - ln -s /usr/local/share/autoconf-2.69/bin/autoconf /usr/bin/autoconf
  when:
    emacs_requires_upgrade and
    autoconf_upgrade_required

- name: Check for emacs previous download
  stat: path=/usr/local/share/emacs-24.5
  register: emacs_src
  when:
    emacs_requires_upgrade

- name: Install latest emacs from source
  unarchive: src=http://mirror.sdunix.com/gnu/emacs/emacs-24.5.tar.gz dest=/usr/local/share copy=no
  when:
    emacs_requires_upgrade and
    not emacs_src.stat.exists

- name: Stat old emacs
  stat: path=/usr/bin/emacs
  register: emacs_in_bin
  when:
    emacs_requires_upgrade

- name: Move old emacs
  command: mv /usr/bin/emacs /usr/bin/emacs.old
  when:
    emacs_in_bin.stat.exists

- name: run autogen.sh
  shell: "{{ item }}"
  args:
    chdir: /usr/local/share/emacs-24.5
  with_items:
    - ./autogen.sh
    - ./configure --with-x=no
    - make
    - make install
    - ln -s /usr/local/share/emacs-24.5/src/emacs /usr/bin/emacs

Upvotes: 0

Views: 9696

Answers (1)

jdspringr07
jdspringr07

Reputation: 19

If you have to do it this way:

Break your role out into 3 separate tasks, include them into the main.yml in your roles folder, and handle your conditional for an entire task. Example:

/path/to/role/tasks/:
main.yml
- include: check_emacs_version.yml
- include: check_auto_conf.yml
- include: install_software.yml 
-- when:check_emacs_version == true

The nice thing about ansible is that is holds variable registration throughout a play and roles are basically a "play", so you can split apart your role into various tasks to clean it up. If you find yourself abusing the "when" conditionals, it's most likely time to split the role into separate tasks.

Upvotes: 1

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