Add support for using kamal inside of the generated devcontainer

Kamal requires docker. The docker-in-docker devcontainer feature allow
running docker inside the container.

railties/CHANGELOG.md

@@ -1,3 +1,9 @@
+*   Add Kamal support for devcontainers
+
+    Previously generated devcontainer could not use docker and therefore Kamal.
+
+    *Joé Dupuis*
+
 ## Rails 8.0.0.beta1 (September 26, 2024) ##
 
 *   Exit `rails g` with code 1 if generator could not be found.

railties/lib/rails/commands/devcontainer/devcontainer_command.rb

@@ -27,6 +27,7 @@ def devcontainer_options
             redis: !!((defined?(ActionCable) && !defined?(SolidCable)) || (defined?(ActiveJob) && !defined?(SolidQueue))),
             system_test: File.exist?("test/application_system_test_case.rb"),
             node: File.exist?(".node-version"),
+            kamal: File.exist?("config/deploy.yml"),
           }
         end
 

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -266,6 +266,7 @@ def devcontainer
       devcontainer_options = {
         database: options[:database],
         redis: options[:skip_solid] && !(options[:skip_action_cable] && options[:skip_active_job]),
+        kamal: !options[:skip_kamal],
         system_test: depends_on_system_test?,
         active_storage: !options[:skip_active_storage],
         dev: options[:dev],

railties/lib/rails/generators/rails/devcontainer/devcontainer_generator.rb

@@ -26,6 +26,10 @@ class DevcontainerGenerator < Base # :nodoc:
       class_option :dev, type: :boolean, default: false,
                     desc: "For applications pointing to a local Rails checkout"
 
+      class_option :kamal, type: :boolean, default: true,
+                    desc: "Include configuration for Kamal"
+
+
       source_paths << File.expand_path(File.join(base_name, "app", "templates"), base_root)
 
       def create_devcontainer
@@ -80,6 +84,7 @@ def container_env
           @container_env["CAPYBARA_SERVER_PORT"] = "45678" if options[:system_test]
           @container_env["SELENIUM_HOST"] = "selenium" if options[:system_test]
           @container_env["REDIS_URL"] = "redis://redis:6379/1" if options[:redis]
+          @container_env["KAMAL_REGISTRY_PASSWORD"] = "$KAMAL_REGISTRY_PASSWORD" if options[:kamal]
           @container_env["DB_HOST"] = database.name if database.service
 
           @container_env
@@ -105,6 +110,7 @@ def features
 
           @features["ghcr.io/rails/devcontainer/features/activestorage"] = {} if options[:active_storage]
           @features["ghcr.io/devcontainers/features/node:1"] = {} if options[:node]
+          @features["ghcr.io/devcontainers/features/docker-in-docker:2"] = {} if options[:kamal]
 
           @features.merge!(database.feature) if database.feature
 

railties/test/commands/devcontainer_test.rb

@@ -22,6 +22,7 @@ class Rails::Command::DevcontainerTest < ActiveSupport::TestCase
     assert_match "redis: false", output
     assert_match "system_test: true", output
     assert_match "node: false", output
+    assert_match "kamal: false", output
   end
 
   test "generates dev container for without solid gems" do

railties/test/generators/app_generator_test.rb

@@ -1255,10 +1255,12 @@ def test_devcontainer
     assert_devcontainer_json_file do |content|
       assert_equal "my_app", content["name"]
       assert_equal "45678", content["containerEnv"]["CAPYBARA_SERVER_PORT"]
+      assert_equal "$KAMAL_REGISTRY_PASSWORD", content["containerEnv"]["KAMAL_REGISTRY_PASSWORD"]
       assert_equal "selenium", content["containerEnv"]["SELENIUM_HOST"]
       assert_includes content["features"].keys, "ghcr.io/rails/devcontainer/features/activestorage"
       assert_includes content["features"].keys, "ghcr.io/devcontainers/features/github-cli:1"
       assert_includes content["features"].keys, "ghcr.io/rails/devcontainer/features/sqlite3"
+      assert_includes content["features"].keys, "ghcr.io/devcontainers/features/docker-in-docker:2"
       assert_includes(content["forwardPorts"], 3000)
     end
     assert_file(".devcontainer/Dockerfile") do |content|
@@ -1294,6 +1296,15 @@ def test_devcontainer
     end
   end
 
+  def test_devcontainer_skip_kamal
+    run_generator [destination_root, "--devcontainer", "--name=my-app", "--skip-kamal"]
+
+    assert_devcontainer_json_file do |devcontainer_json|
+      assert_not_includes devcontainer_json["features"].keys, "ghcr.io/devcontainers/features/docker-in-docker:2"
+      assert_not_includes devcontainer_json["containerEnv"].keys, "KAMAL_REGISTRY_PASSWORD"
+    end
+  end
+
   def test_devcontainer_include_redis_skipping_solid
     run_generator [destination_root, "--devcontainer", "--name=my-app", "--skip-solid"]
 

railties/test/generators/devcontainer_generator_test.rb

@@ -283,6 +283,24 @@ def test_redis_option_skip
         end
       end
 
+      def test_kamal_option_default
+        run_generator
+
+        assert_devcontainer_json_file do |devcontainer_json|
+          assert_includes devcontainer_json["features"].keys, "ghcr.io/devcontainers/features/docker-in-docker:2"
+          assert_equal "$KAMAL_REGISTRY_PASSWORD", devcontainer_json["containerEnv"]["KAMAL_REGISTRY_PASSWORD"]
+        end
+      end
+
+      def test_kamal_option_skip
+        run_generator ["--skip-kamal"]
+
+        assert_devcontainer_json_file do |devcontainer_json|
+          assert_not_includes devcontainer_json["features"].keys, "ghcr.io/devcontainers/features/docker-in-docker:2"
+          assert_not_includes devcontainer_json["containerEnv"].keys, "KAMAL_REGISTRY_PASSWORD"
+        end
+      end
+
       def test_system_test_option_default
         copy_application_system_test_case