Support 'Stopping' the AWS backend

Which means just destroying the build machine.

3 files changed, 30 insertions, 0 deletions

diff --git a/app/controllers/backends/terraform_aws_controller.rb b/app/controllers/backends/terraform_aws_controller.rb
index ab9b323..e5b66d4 100644
--- a/app/controllers/backends/terraform_aws_controller.rb
+++ b/app/controllers/backends/terraform_aws_controller.rb
@@ -65,6 +65,10 @@ class Backends::TerraformAwsController < ApplicationController
       Backends::TerraformAwsJob.enqueue(@backend.id, :destroy_backend)
 
       flash[:notice] = 'Destroying the backend'
+    when 'Stop'
+      Backends::TerraformAwsJob.enqueue(@backend.id, :stop_backend)
+
+      flash[:notice] = 'Stopping the backend'
     when 'Deploy'
       Backends::TerraformAwsJob.enqueue(@backend.id, :deploy_backend)
 
diff --git a/app/models/backends/terraform_aws/backend_methods.rb b/app/models/backends/terraform_aws/backend_methods.rb
index f8338a4..89509bd 100644
--- a/app/models/backends/terraform_aws/backend_methods.rb
+++ b/app/models/backends/terraform_aws/backend_methods.rb
@@ -78,6 +78,19 @@ module Backends::TerraformAws::BackendMethods
     end
   end
 
+  def stop_backend
+    TerraformWorkingDirectory.new(
+      terraform_state_id,
+      'terraform/aws/backend'
+    ).within_working_directory do
+      RubyTerraform.destroy(
+        vars: backend_terraform_variables,
+        target: 'aws_spot_instance_request.main',
+        force: true
+      )
+    end
+  end
+
   def available_data_snapshots
     GovukGuix::DataSnapshot.where(backend: self)
   end
diff --git a/app/views/backends/terraform_aws/show.html.erb b/app/views/backends/terraform_aws/show.html.erb
index 6a576ab..0160798 100644
--- a/app/views/backends/terraform_aws/show.html.erb
+++ b/app/views/backends/terraform_aws/show.html.erb
@@ -85,6 +85,19 @@ License along with the GOV.UK Mini Environment Admin.  If not, see
             </p>
           </li>
           <li class="list-group-item">
+            <%= submit_tag("Stop",
+                           role: 'button',
+                           style: 'margin-bottom: 5px;',
+                           class: 'btn btn-lg btn-warning btn-block')
+            %>
+            <p class="list-group-item-text">
+              Run Terraform to stop this backend, terminating the
+              build machine used to build new mini
+              environments. Existing environments will continue to
+              run, but new environments cannot be created.
+            </p>
+          </li>
+          <li class="list-group-item">
             <%= submit_tag("Destroy",
                            role: 'button',
                            style: 'margin-bottom: 5px;',