Install yarn if needed in javascript jobs

Some javascript projects use yarn for dependencies instead of raw npm.
If a yarn.lock file is detected in the zuul_work_dir, install yarn and
use yarn to install dependencies.

Needed-By: I5864e1b2f9952fbc35b08ebdef348c4917564c37
Change-Id: I9ae7dd3b33b2b607c1c5a17632e2aeb12e339d15

playbooks/javascript/pre-test.yaml

@@ -5,6 +5,7 @@
       bindep_dir: "{{ zuul_work_dir }}"
     - test-setup
     - install-nodejs
+    - install-yarn
     # nodejs-test-dependencies requires sudo,
     # so we cannot inherit pre.yaml from javascript-base.
     - nodejs-test-dependencies

playbooks/javascript/pre.yaml

@@ -5,5 +5,6 @@
       bindep_dir: "{{ zuul_work_dir }}"
     - test-setup
     - install-nodejs
+    - install-yarn
     - revoke-sudo
     - install-javascript-packages

roles/install-javascript-packages/tasks/main.yaml

@@ -1,6 +1,23 @@
+- name: Check for yarn.lock file
+  stat:
+    path: "{{ zuul_work_dir }}/yarn.lock"
+    get_checksum: false
+    get_mime: false
+    get_md5: false
+  register: yarn_lock
+
+- name: Install yarn dependencies
+  command: yarn install
+  environment:
+    DISPLAY: ':99'
+  args:
+    chdir: "{{ zuul_work_dir }}"
+  when: yarn_lock.stat.exists
+
 - name: Install npm dependencies
   command: npm install --verbose
   environment:
     DISPLAY: ':99'
   args:
     chdir: "{{ zuul_work_dir }}"
+  when: not yarn_lock.stat.exists

roles/install-yarn/README.rst

@@ -0,0 +1,8 @@
+Install yarn from yarnpkg repos
+
+**Role Variables**
+
+.. zuul:rolevar:: zuul_work_dir
+   :default: {{ zuul.project.src_dir }}
+
+   The directory to work in.

roles/install-yarn/defaults/main.yaml

@@ -0,0 +1 @@
+zuul_work_dir: "{{ zuul.project.src_dir }}"

roles/install-yarn/tasks/Debian.yaml

@@ -0,0 +1,14 @@
+- name: Add yarnpkg repository key
+  apt_key:
+    url: https://dl.yarnpkg.com/debian/pubkey.gpg
+  become: yes
+
+- name: Add yarnpkg apt source repository
+  apt_repository:
+    repo: "deb https://dl.yarnpkg.com/debian/ stable main"
+    state: present
+    update_cache: yes
+  become: yes
+
+- name: Install yarn
+  include: yarn.yaml

roles/install-yarn/tasks/RedHat.yaml

@@ -0,0 +1,8 @@
+- name: Add yarnpkg repo file
+  get_url:
+    url: https://dl.yarnpkg.com/rpm/yarn.repo
+    dest: /etc/yum.repos.d/yarn.repo
+  become: yes
+
+- name: Install yarn
+  include: yarn.yaml

roles/install-yarn/tasks/main.yaml

@@ -0,0 +1,15 @@
+- name: Check for yarn.lock file
+  stat:
+    path: "{{ zuul_work_dir }}/yarn.lock"
+    get_checksum: false
+    get_mime: false
+    get_md5: false
+  register: yarn_lock
+
+- name: Install yarn if needed
+  include: "{{ item }}"
+  with_first_found:
+    - "{{ ansible_distribution }}.yaml"
+    - "{{ ansible_os_family }}.yaml"
+  when:
+    - yarn_lock.stat.exists

roles/install-yarn/tasks/yarn.yaml

@@ -0,0 +1,11 @@
+- name: Install yarn from yarnpkg.com
+  package:
+    name: yarn
+    state: latest
+  become: yes
+  tags:
+    # Ignore ANSIBLE0010: We really want latest version
+    - skip_ansible_lint
+
+- name: Output yarn version
+  command: yarn --version