Ansible

Structure

Figure 1: directory structure

Figure 1: directory structure

Playbook

The following playbook has been created:

- name: Base setup
  hosts: api
  gather_facts: no
  become: yes
  tags:
    - base

  vars:
    USER: "workday"
    PACKAGES:
      - git
      - wget

  pre_tasks:
    - name: Install system packages
      apt:
        name: "{{ PACKAGES }}"
        update_cache: yes

  roles:
    - role: user

- name: Setup Golang
  hosts: api
  gather_facts: no
  become: yes
  tags:
    - go

  vars:
    GO_VERSION: "1.13.3"

  roles:
    - role: go

- name: Setup build tool Mage
  hosts: api
  gather_facts: no
  become: yes
  tags:
    - buildtool

  vars:
    USER: "workday"

  roles:
    - role: mage

- name: Setup process manager pm2
  hosts: api
  gather_facts: no
  become: yes
  tags:
    - pm2

  roles:
    - role: pm2
Code Snippet 1: .packer/ansible/workday.yml

It has four main tasks, each of them run a role and has a tag defined to allow running a one or more tasks instead of the whole playbook.

The use of become: yes is needed because the playbook is ran using the vagrant user, therefore privileged rights are needed.

Roles

  1. Base setup: This role installs some base packages needed and creates an APP user (workday) using a variable, this allows to easily change the user name without having to change the role.

    ​- name: Create App user
  user:
    name: "{{ USER }}"
    shell: "/bin/bash"
    create_home: True
    Code Snippet 2: .packer/ansible/roles/user/tasks/main.yml

  2. Setup Golang: This role downloads and installs a specific Go version given as a variable, it also creates a symlink of the Go binary to /usr/local/bin/go.

    ​- name: Check if go is already installed
  stat:
    path: "/usr/local/bin/go"
  register: go_binary

- name: Download Go archive
  get_url:
    url: "https://dl.google.com/go/go{{ GO_VERSION }}.linux-amd64.tar.gz"
    dest: "/tmp/go{{ GO_VERSION }}.linux-amd.tar.gz"
  when: not go_binary.stat.exists

- name: Unarchive Go archive
  unarchive:
    src: "/tmp/go{{ GO_VERSION }}.linux-amd.tar.gz"
    dest: "/usr/local"
    remote_src: yes
  when: not go_binary.stat.exists

- name: Symlink Go binary
  file:
    src: "/usr/local/go/bin/go"
    dest: "/usr/local/bin/go"
    state: link
  when: not go_binary.stat.exists
    Code Snippet 3: .packer/ansible/roles/go/tasks/main.yml

  3. Setup Mage: This is the build tool used in this project, this role installs Mage in the GOROOT path of the user given as a variable.

    ​- name: Create GOROOT for user
  file:
    path: "/home/{{ USER }}/go/src"
    state: directory
    owner: "{{ USER }}"
    group: "{{ USER }}"

- name: Check if mage is installed
  stat:
    path: "/home/{{ USER }}/go/bin/mage"
  register: mage

- name: Install mage
  environment:
    GOROOT: "/home/{{ USER }}/go"
  shell: "sudo -u {{ USER }} go get github.com/magefile/mage"
  when: not mage.stat.exists
    Code Snippet 4: .packer/ansible/roles/mage/tasks/main.yml

  4. Setup Process Manager: A role to install npm and pm2, which will be used once we deploy the project.

    ​- name: Install npm
  apt:
    name: npm

- name: Check if pm2 is installed
  stat:
    path: "/usr/local/bin/pm2"
  register: pm2

- name: Install pm2
  shell: "npm install -g pm2"
  when: not pm2.stat.exists
    Code Snippet 5: .packer/ansible/roles/pm2/tasks/main.yml

Every role has checks to make sure the tasks are idempotent, this means we can run the playbook as many times as we want and we will get the same result.

Inventory

The inventory created is for a packer environment, that’s why the ansible host points to localhost.

---
all:
  hosts:
    api:
      ansible_host: "127.0.0.1"
Code Snippet 6: .packer/ansible/env/packer/hosts.yml