From c2c77ea26069b6d3390b5fd60f8464efadc9c485 Mon Sep 17 00:00:00 2001
From: Kartiki Sharma <kartiki.sharma@shopify.com>
Date: Tue, 19 Mar 2024 11:19:39 -0400
Subject: [PATCH] Stack: update `build_deploy` to pass `allow_concurrency`

Add unit tests
---
 CHANGELOG.md                                  |  2 ++
 README.md                                     |  5 ++++
 .../shipit/api/deploys_controller.rb          |  6 ++++-
 app/models/shipit/stack.rb                    |  4 ++--
 .../api/deploys_controller_test.rb            | 23 +++++++++++++++++++
 5 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ba8a009f4..0a5c3c017 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,8 @@
 * Migrate from legacy Rails secrets to credentials (#1326)
   * Rails secrets were [deprecated in Rails 7.1](https://github.com/rails/rails/pull/48472)
   * [Guide on credentials](https://guides.rubyonrails.org/security.html#custom-credentials)
+* For deployments, `allow_concurrency` defaults to the same value as `force`. If wanted, it can be set separately by passing the intended value for `allow_concurrency` to `build_deploy` method
+
 
 # 0.39.0
 
diff --git a/README.md b/README.md
index e8a6f17f1..a48fa65e7 100644
--- a/README.md
+++ b/README.md
@@ -357,6 +357,11 @@ For example:
 fetch:
   curl --silent https://app.example.com/services/ping/version
 ```
+
+**Note:** Currently, deployments in emergency mode are configured to occur concurrently via [the `build_deploy` method](https://github.com/Shopify/shipit-engine/blob/main/app/models/shipit/stack.rb),
+whose `allow_concurrency` keyword argument defaults to `force`, where `force` is true when emergency mode is enabled. 
+If you'd like to separate these two from one another, override this method as desired in your service.
+
 <h3 id="kubernetes">Kubernetes</h3>
 
 **<code>kubernetes</code>** allows to specify a Kubernetes namespace and context to deploy to.
diff --git a/app/controllers/shipit/api/deploys_controller.rb b/app/controllers/shipit/api/deploys_controller.rb
index d80dedbfb..3ccb3f077 100644
--- a/app/controllers/shipit/api/deploys_controller.rb
+++ b/app/controllers/shipit/api/deploys_controller.rb
@@ -11,6 +11,7 @@ def index
       params do
         requires :sha, String, length: { in: 6..40 }
         accepts :force, Boolean, default: false
+        accepts :allow_concurrency, Boolean
         accepts :require_ci, Boolean, default: false
         accepts :env, Hash, default: {}
       end
@@ -18,7 +19,10 @@ def create
         commit = stack.commits.by_sha(params.sha) || param_error!(:sha, 'Unknown revision')
         param_error!(:force, "Can't deploy a locked stack") if !params.force && stack.locked?
         param_error!(:require_ci, "Commit is not deployable") if params.require_ci && !commit.deployable?
-        deploy = stack.trigger_deploy(commit, current_user, env: params.env, force: params.force)
+
+        allow_concurrency = params.allow_concurrency.nil? ? params.force : params.allow_concurrency
+        deploy = stack.trigger_deploy(commit, current_user, env: params.env, force: params.force,
+          allow_concurrency: allow_concurrency)
         render_resource(deploy, status: :accepted)
       end
     end
diff --git a/app/models/shipit/stack.rb b/app/models/shipit/stack.rb
index 4f2642f89..23767f254 100644
--- a/app/models/shipit/stack.rb
+++ b/app/models/shipit/stack.rb
@@ -150,14 +150,14 @@ def trigger_task(definition_id, user, env: nil, force: false)
       task
     end
 
-    def build_deploy(until_commit, user, env: nil, force: false)
+    def build_deploy(until_commit, user, env: nil, force: false, allow_concurrency: force)
       since_commit = last_deployed_commit.presence || commits.first
       deploys.build(
         user_id: user.id,
         until_commit: until_commit,
         since_commit: since_commit,
         env: filter_deploy_envs(env&.to_h || {}),
-        allow_concurrency: force,
+        allow_concurrency: allow_concurrency,
         ignored_safeties: force || !until_commit.deployable?,
         max_retries: retries_on_deploy,
       )
diff --git a/test/controllers/api/deploys_controller_test.rb b/test/controllers/api/deploys_controller_test.rb
index 7a044b8ff..c7ebbf02a 100644
--- a/test/controllers/api/deploys_controller_test.rb
+++ b/test/controllers/api/deploys_controller_test.rb
@@ -120,6 +120,29 @@ class DeploysControllerTest < ApiControllerTestCase
         assert_response :accepted
         assert_json 'status', 'pending'
       end
+
+      test "#create uses allow_concurrency param when provided" do
+        @stack.update!(lock_reason: 'Something broken')
+
+        assert_difference -> { @stack.deploys.count }, 1 do
+          post :create, params: { stack_id: @stack.to_param, sha: @commit.sha, force: 'true', allow_concurrency: 'false' }
+        end
+        assert_response :accepted
+        assert_json 'status', 'pending'
+        refute @stack.deploys.last.allow_concurrency
+      end
+
+      test "#create defaults allow_concurrency to force param when not provided" do
+        @stack.update!(lock_reason: 'Something broken')
+        expected_force = true
+
+        assert_difference -> { @stack.deploys.count }, 1 do
+          post :create, params: { stack_id: @stack.to_param, sha: @commit.sha, force: expected_force }
+        end
+        assert_response :accepted
+        assert_json 'status', 'pending'
+        assert_equal expected_force, @stack.deploys.last.allow_concurrency
+      end
     end
   end
 end