From a0f30ac40170f8178d2a3c7517e45bcfa598167e Mon Sep 17 00:00:00 2001
From: Adam Hebden <adamhebden56@gmail.com>
Date: Sat, 17 Apr 2021 17:02:00 +0100
Subject: [PATCH] Symlinking on deploys & Rollback functionality (#8)

* Changes glimesh-web role to symlink deploys with states

* Moves Glimesh shutdown to last possible place

* Removes redundant comment in glimesh-web

* Adds quick Ansible script to rollback Glimesh to prev version

* Forgot to quote Ansible variable

* Adds delegation & deletion to synchronize symlink deploys

* Adds checking /opt/glimesh.tv dir exists

* Changes deploys to use git hash

* Fixed link target by disabling follow

* Fixing missed prod build path to synchronize

* Fixed bad when indent on delete old dirs

* Maybe fixes directory deleting - fully tested in docker
---
 ansible/roles/glimesh-web/tasks/main.yml | 151 ++++++++++++++++++-----
 ansible/web-rollback.yml                 |  34 +++++
 2 files changed, 157 insertions(+), 28 deletions(-)
 create mode 100644 ansible/web-rollback.yml

diff --git a/ansible/roles/glimesh-web/tasks/main.yml b/ansible/roles/glimesh-web/tasks/main.yml
index ea25699..7f5b0a4 100644
--- a/ansible/roles/glimesh-web/tasks/main.yml
+++ b/ansible/roles/glimesh-web/tasks/main.yml
@@ -5,15 +5,15 @@
     name: "{{ inventory_hostname }}"
 
 - name: Ensure .ssh directory exists.
-  file: 
+  file:
     dest: "/root/.ssh"
-    mode: 0700 
-    owner: root 
+    mode: 0700
+    owner: root
     state: directory
 
 - name: Install ssh key
-  copy: 
-    src: "glimesh-deploy" 
+  copy:
+    src: "glimesh-deploy"
     dest: "/root/.ssh/id_rsa"
     mode: 0600
     owner: root
@@ -27,12 +27,12 @@
 
 # - name: install required packages
 #   apt:
-#     pkg: 
-#       - esl-erlang 
-#       - elixir 
-#       - npm 
+#     pkg:
+#       - esl-erlang
+#       - elixir
+#       - npm
 #       - git
-#       - openssl 
+#       - openssl
 #       - imagemagick
 #     state: present
 #     update_cache: yes
@@ -43,8 +43,10 @@
 - name: install rebar
   command: mix local.rebar --force
 
-- name: ensure /tmp/glimesh.tv exists
-  file: path=/tmp/glimesh.tv state=directory
+- name: ensure tmp build dir exists
+  file:
+    path: /tmp/glimesh.tv
+    state: directory
 
 - name: download glimesh.tv
   git:
@@ -62,19 +64,41 @@
     chdir: /tmp/glimesh.tv
   register: glimesh_git_hash
 
-- name: change version 
+- name: change version
   lineinfile:
     path: /tmp/glimesh.tv/mix.exs
     regexp: '^\s+version: .*$'
     line: "version: \"0.1.0+{{ glimesh_git_hash.stdout }}\","
 
+- set_fact:
+    deploy_dest: "/opt/glimesh.tv-{{ glimesh_git_hash.stdout }}"
+
+## Check we should deploy
+
+- name: Get currently deployed hash
+  stat:
+    path: /opt/glimesh.tv
+    follow: no
+    get_checksum: no
+  register: current_deploy
+
+- name: Same version deployed?
+  pause:
+    prompt: |
+      WARNING: Latest version is already deployed.
+      Pess Enter to continue
+  delegate_to: localhost
+  when: current_deploy.stat.exists and current_deploy.stat.lnk_target == deploy_dest
+  register: same_deploy
+
+## Build the deploy
+
 - name: install mix dependencies
-  command: mix do deps.get, deps.compile 
+  command: mix do deps.get, deps.compile
   args:
     chdir: /tmp/glimesh.tv
   environment:
     MIX_ENV: prod
-  # when: glimesh.changed
 
 - name: install npm asset deps
   command: npm --prefix ./assets ci --progress=false --no-audit --loglevel=error
@@ -95,15 +119,41 @@
   # when: glimesh.changed
 
 - name: build glimesh.tv
-  command: mix do compile --force, release --force --overwrite 
+  command: mix do compile --force, release --force --overwrite
   args:
     chdir: /tmp/glimesh.tv
   environment:
     MIX_ENV: prod
   # when: glimesh.changed
 
+- name: Ensure new directory exists
+  file:
+    path: "{{ deploy_dest }}"
+    state: directory
+    owner: nobody
+    recurse: yes
+
+- name: Copy newly built files to new host
+  synchronize:
+    src: /tmp/glimesh.tv/_build/prod
+    dest: "{{ deploy_dest }}"
+    links: yes
+    delete: yes
+  delegate_to: "{{ inventory_hostname }}"
+
+- name: Check permissions
+  file:
+    path: "{{ deploy_dest }}"
+    owner: nobody
+    recurse: yes
+
+## Change the service
+
 - name: setup unit file for glimesh.tv
-  template: src=glimesh.service.j2 dest=/etc/systemd/system/glimesh.service mode=644
+  template:
+    src: glimesh.service.j2
+    dest: /etc/systemd/system/glimesh.service
+    mode: 644
   tags: config
 
 - name: reload systemd immediately
@@ -111,22 +161,20 @@
     daemon_reload: yes
 
 - name: gracefully shut down old glimesh app
-  systemd: 
+  systemd:
     name: glimesh
     state: stopped
 
-# Copying the file will automatically restart the daemon.
-- name: copy built glimesh.tv
-  command: cp -Rf /tmp/glimesh.tv/_build/prod /opt/glimesh.tv 
-
-- name: permissions
+- name: Change the symlink
   file:
-    path: /opt/glimesh.tv
+    src: "{{ deploy_dest }}"
+    dest: /opt/glimesh.tv
+    state: link
     owner: nobody
-    recurse: yes
+    force: yes
 
 - name: start new glimesh app
-  systemd: 
+  systemd:
     name: glimesh
     state: started
 
@@ -136,5 +184,52 @@
     delay: 5
 
 - name: pause to make sure the other node can take over
-  pause: 
-    seconds: 15
\ No newline at end of file
+  pause:
+    seconds: 15
+
+- name: Add a symlink to the old deploy for ease of rollback
+  file:
+    src: "{{ current_deploy.stat.lnk_target }}"
+    dest: /opt/glimesh.tv-old
+    state: link
+    owner: nobody
+    force: yes
+
+- name: Cleanup old directories
+  block:
+    - name: Get currently deployed dest
+      stat:
+        path: /opt/glimesh.tv
+        follow: no
+        get_checksum: no
+      register: gtv_current
+
+    - name: Get old deployed dest
+      stat:
+        path: /opt/glimesh.tv-old
+        follow: no
+        get_checksum: no
+      register: gtv_old
+
+    # Cleanup
+    - name: Find all deploy folders
+      find:
+        paths: /opt
+        file_type: directory
+        use_regex: yes
+        patterns: "^glimesh.tv-([a-zA-Z0-9]+)$"
+        recurse: no
+      register: all_deploys
+
+    - name: Delete old directories
+      file:
+        path: "{{ item }}"
+        state: absent
+      when:
+        - item != '/opt/glimesh.tv-old'
+        - gtv_current.stat.exists == False or item != gtv_current.stat.lnk_target
+        - gtv_old.stat.exists == False or item != gtv_old.stat.lnk_target
+      with_items: "{{ all_deploys.files | map(attribute='path') | list }}"
+
+  tags:
+    - cleanup
diff --git a/ansible/web-rollback.yml b/ansible/web-rollback.yml
new file mode 100644
index 0000000..3d4d9bd
--- /dev/null
+++ b/ansible/web-rollback.yml
@@ -0,0 +1,34 @@
+- name: web
+  hosts: web
+  serial: 1
+
+  tasks:
+    - name: Get old deployed hash
+      stat:
+        path: /opt/glimesh.tv-old
+        follow: no
+        get_checksum: no
+      register: old_deploy
+
+    - name: Change the symlink
+      file:
+        src: "{{ old_deploy.stat.lnk_target }}"
+        dest: /opt/glimesh.tv
+        state: link
+        owner: nobody
+        force: yes
+
+    - name: restart glimesh
+      systemd:
+        name: glimesh
+        daemon_reload: yes
+        state: restarted
+
+    - name: wait for service to be online
+      wait_for:
+        port: 8080
+        delay: 5
+
+    - name: pause to make sure the other node can take over
+      pause:
+        seconds: 15