Display app version in the footer using the git tag

- Added a new Terraform variable `version` and passed it to the Rails app via task_envs to support version number display in deployments.
- Updated the GitHub Actions `deploy-infrastructure.yml` workflow to dynamically extract the latest Git tag before running `terraform plan`. If no tag is found, the version defaults to "unknown" with a warning.
- Modified the `bin/setup` script to detect the latest Git tag locally and set `APP_VERSION` dynamically for development.
- Updated controller logic to only display version if it matches the `vX.Y.Z.x` format.
- Added logic to conditionally render the version in the footer only when valid.

Author: murugapl

.github/workflows/deploy-infrastructure.yml

@@ -4,6 +4,10 @@ run-name: Deploy infrastructure for ${{ inputs.environment }}
 on:
   workflow_dispatch:
     inputs:
+      git_ref_to_deploy:
+        description: "Git ref string for displaying app version (e.g., tag, branch or sha)"
+        required: false
+        type: string
       environment:
         description: Deployment environment
         required: true
@@ -22,6 +26,9 @@ on:
         type: string
   workflow_call:
     inputs:
+      git_ref_to_deploy:
+          required: false
+          type: string
       environment:
         description: Deployment environment
         required: true
@@ -87,12 +94,16 @@ jobs:
         run: sudo snap install --classic aws-cli
       - name: Check if any deployments are running
         run: ../scripts/check-for-running-deployments.sh ${{ inputs.environment }}
+      - name: Set Mavis app version
+        run: |
+          APP_VERSION="${{ inputs.git_ref_to_deploy }}"
+          echo "APP_VERSION=$APP_VERSION" >> $GITHUB_ENV
       - name: Terraform Plan
         id: plan
         run: |
           set -e
           terraform init -backend-config="env/${{ inputs.environment }}-backend.hcl" -upgrade
-          terraform plan -var="image_digest=$DIGEST" -var-file="env/${{ inputs.environment }}.tfvars" \
+          terraform plan -var="image_digest=$DIGEST" -var="app_version=$APP_VERSION" -var-file="env/${{ inputs.environment }}.tfvars" \
           -out ${{ runner.temp }}/tfplan | tee ${{ runner.temp }}/tf_stdout
       - name: Validate the changes
         run: |

.github/workflows/deploy.yml

@@ -85,6 +85,7 @@ jobs:
     with:
       environment: ${{ inputs.environment }}
       image_tag: ${{ needs.determine-git-sha.outputs.git-sha }}
+      git_ref_to_deploy: ${{ inputs.git_ref_to_deploy || github.ref_name }}
   deploy-application:
     permissions:
       id-token: write

app/controllers/application_controller.rb

@@ -15,6 +15,7 @@ class ApplicationController < ActionController::Base
   before_action :set_show_navigation
   before_action :set_privacy_policy_url
   before_action :authenticate_basic
+  before_action :set_app_version
 
   after_action :verify_policy_scoped, if: -> { Rails.env.local? }
 
@@ -32,6 +33,10 @@ class UnprocessableEntity < StandardError
   rescue_from Pundit::NotAuthorizedError, with: :user_not_authorized
 
   private
+  
+  def set_app_version
+    @app_version = APP_VERSION.match?(/\Av\d+(?:\.\d+)*/) ? APP_VERSION : nil
+  end  
 
   def set_selected_organisation
     return if Settings.cis2.enabled

app/views/layouts/application.html.erb

@@ -60,6 +60,11 @@
                   <%= link_to "#{t("service.guide.title")} (opens in a new tab)", @service_guide_url, classes: "nhsuk-footer__list-item-link", target: "_blank" %>
                 </li>
               <% end %>
+              <% if @app_version %>
+                <li class="nhsuk-footer__list-item nhsuk-footer-default__list-item nhsuk-u-secondary-text-color">
+                  <%= @app_version %>
+                </li>
+              <% end %>
             </ul>
             <p class="nhsuk-footer__copyright">&copy; NHS England</p>
           </div>

bin/setup

@@ -28,6 +28,16 @@ FileUtils.chdir APP_ROOT do
   puts "\n== Removing old logs and tempfiles =="
   system! "bin/rails log:clear tmp:clear"
 
+  puts "\n== Detecting app version from git tag =="
+
+  git_branch = `git rev-parse --abbrev-ref HEAD 2>/dev/null`.strip
+  if git_branch == "HEAD"
+    puts "Warning: Not on a branch. APP_VERSION not set."
+  else
+    ENV["APP_VERSION"] = git_branch unless git_branch.empty?
+    puts "Detected APP_VERSION: #{ENV["APP_VERSION"]}"
+  end
+
   unless ARGV.include?("--skip-server")
     puts "\n== Starting development server =="
     STDOUT.flush # flush the output before exec(2) so that it displays

config/initializers/version.rb

@@ -0,0 +1 @@
+APP_VERSION = ENV.fetch('APP_VERSION', 'unknown')

terraform/app/variables.tf

@@ -157,6 +157,12 @@ variable "enable_splunk" {
   nullable    = false
 }
 
+variable "app_version" {
+  type        = string
+  default     = "n/a"
+  description = "The version of Mavis being deployed."
+}
+
 locals {
   is_production = var.environment == "production"
   parameter_store_variables = tomap({
@@ -202,8 +208,13 @@ locals {
     {
       name  = "MAVIS__SPLUNK__ENABLED"
       value = var.enable_splunk ? "true" : "false"
+    },
+    {
+      name  = "APP_VERSION"
+      value = var.app_version
     }
   ]
+
   task_secrets = concat([
     {
       name      = var.db_secret_arn == null ? "DB_CREDENTIALS" : "DB_SECRET"