Allow accessory only configurations

If there are accessories defined in the configuration, we'll not require
servers to be defined as well.

This allows for accessory-only configurations which allows you to run
external images with kamal-proxy for zero-downtime deployments.

We don't manage image cleanup for accessories though so the user will
need to deal with that themselves.

test/configuration_test.rb

@@ -30,7 +30,7 @@ class ConfigurationTest < ActiveSupport::TestCase
   %i[ service image registry ].each do |key|
     test "#{key} config required" do
       assert_raise(Kamal::ConfigurationError) do
-        Kamal::Configuration.new @deploy.tap { _1.delete key }
+        Kamal::Configuration.new @deploy.tap { |config| config.delete key }
       end
     end
   end
@@ -38,21 +38,36 @@ class ConfigurationTest < ActiveSupport::TestCase
   %w[ username password ].each do |key|
     test "registry #{key} required" do
       assert_raise(Kamal::ConfigurationError) do
-        Kamal::Configuration.new @deploy.tap { _1[:registry].delete key }
+        Kamal::Configuration.new @deploy.tap { |config| config[:registry].delete key }
       end
     end
   end
 
   test "service name valid" do
     assert_nothing_raised do
-      Kamal::Configuration.new(@deploy.tap { _1[:service] = "hey-app1_primary" })
-      Kamal::Configuration.new(@deploy.tap { _1[:service] = "MyApp" })
+      Kamal::Configuration.new(@deploy.tap { |config| config[:service] = "hey-app1_primary" })
+      Kamal::Configuration.new(@deploy.tap { |config| config[:service] = "MyApp" })
     end
   end
 
   test "service name invalid" do
     assert_raise(Kamal::ConfigurationError) do
-      Kamal::Configuration.new @deploy.tap { _1[:service] = "app.com" }
+      Kamal::Configuration.new @deploy.tap { |config| config[:service] = "app.com" }
+    end
+  end
+
+  test "servers required" do
+    assert_raise(Kamal::ConfigurationError) do
+      Kamal::Configuration.new @deploy.tap { |config| config.delete(:servers) }
+    end
+  end
+
+  test "servers not required with accessories" do
+    assert_nothing_raised do
+      @deploy.delete(:servers)
+      @deploy[:accessories] = { "foo" => { "image" => "foo/bar", "host" => "1.1.1.1" } }
+
+      Kamal::Configuration.new(@deploy)
     end
   end
 
@@ -250,7 +265,7 @@ class ConfigurationTest < ActiveSupport::TestCase
   test "destination required" do
     dest_config_file = Pathname.new(File.expand_path("fixtures/deploy_for_required_dest.yml", __dir__))
 
-    assert_raises(Kamal::ConfigurationError) do
+    assert_raises(ArgumentError, "You must specify a destination") do
       config = Kamal::Configuration.create_from config_file: dest_config_file
     end
 

test/integration/accessory_test.rb

@@ -21,6 +21,32 @@ class AccessoryTest < IntegrationTest
     assert_accessory_not_running :busybox
   end
 
+  test "proxied: boot, stop, start, restart, logs, remove" do
+    @app = "app_with_proxied_accessory"
+
+    kamal :proxy, :boot
+
+    kamal :accessory, :boot, :netcat
+    assert_accessory_running :netcat
+    assert_netcat_is_up
+
+    kamal :accessory, :stop, :netcat
+    assert_accessory_not_running :netcat
+    assert_netcat_not_found
+
+    kamal :accessory, :start, :netcat
+    assert_accessory_running :netcat
+    assert_netcat_is_up
+
+    kamal :accessory, :restart, :netcat
+    assert_accessory_running :netcat
+    assert_netcat_is_up
+
+    kamal :accessory, :remove, :netcat, "-y"
+    assert_accessory_not_running :netcat
+    assert_netcat_not_found
+  end
+
   private
     def assert_accessory_running(name)
       assert_match /registry:4443\/busybox:1.36.0   "sh -c 'echo \\"Start/, accessory_details(name)
@@ -33,4 +59,25 @@ class AccessoryTest < IntegrationTest
     def accessory_details(name)
       kamal :accessory, :details, name, capture: true
     end
+
+    def assert_netcat_is_up
+      response = netcat_response
+      debug_response_code(response, "200")
+      assert_equal "200", response.code
+    end
+
+    def assert_netcat_not_found
+      response = netcat_response
+      debug_response_code(response, "404")
+      assert_equal "404", response.code
+    end
+
+    def netcat_response
+      uri = URI.parse("http://127.0.0.1:12345/up")
+      http = Net::HTTP.new(uri.host, uri.port)
+      request = Net::HTTP::Get.new(uri)
+      request["Host"] = "netcat"
+
+      http.request(request)
+    end
 end

test/integration/docker/deployer/app_with_proxied_accessory/config/deploy.yml

@@ -1,7 +1,5 @@
 service: app_with_proxied_accessory
 image: app_with_proxied_accessory
-servers:
-  - vm1
 env:
   clear:
     CLEAR_TOKEN: 4321
@@ -24,15 +22,13 @@ accessories:
     service: custom-busybox
     image: registry:4443/busybox:1.36.0
     cmd: sh -c 'echo "Starting busybox..."; trap exit term; while true; do sleep 1; done'
-    roles:
-      - web
+    host: vm1
   netcat:
     service: netcat
     image: registry:4443/busybox:1.36.0
     cmd: >
       sh -c 'echo "Starting netcat..."; while true; do echo -e "HTTP/1.1 200 OK\r\nContent-Length: 11\r\n\r\nHello Ruby" | nc -l -p 80; done'
-    roles:
-      - web
+    host: vm1
     port: 12345:80
     proxy:
       host: netcat

test/integration/proxied_accessory_test.rb

@@ -1,63 +0,0 @@
-require_relative "integration_test"
-
-class ProxiedAccessoryTest < IntegrationTest
-  test "boot, stop, start, restart, logs, remove" do
-    @app = "app_with_proxied_accessory"
-
-    kamal :deploy
-
-    kamal :accessory, :boot, :netcat
-    assert_accessory_running :netcat
-    assert_netcat_is_up
-
-    kamal :accessory, :stop, :netcat
-    assert_accessory_not_running :netcat
-    assert_netcat_not_found
-
-    kamal :accessory, :start, :netcat
-    assert_accessory_running :netcat
-    assert_netcat_is_up
-
-    kamal :accessory, :restart, :netcat
-    assert_accessory_running :netcat
-    assert_netcat_is_up
-
-    kamal :accessory, :remove, :netcat, "-y"
-    assert_accessory_not_running :netcat
-    assert_netcat_not_found
-  end
-
-  private
-    def assert_accessory_running(name)
-      assert_match /registry:4443\/busybox:1.36.0   "sh -c 'echo \\"Start/, accessory_details(name)
-    end
-
-    def assert_accessory_not_running(name)
-      assert_no_match /registry:4443\/busybox:1.36.0   "sh -c 'echo \\"Start/, accessory_details(name)
-    end
-
-    def accessory_details(name)
-      kamal :accessory, :details, name, capture: true
-    end
-
-    def assert_netcat_is_up
-      response = netcat_response
-      debug_response_code(response, "200")
-      assert_equal "200", response.code
-    end
-
-    def assert_netcat_not_found
-      response = netcat_response
-      debug_response_code(response, "404")
-      assert_equal "404", response.code
-    end
-
-    def netcat_response
-      uri = URI.parse("http://127.0.0.1:12345/up")
-      http = Net::HTTP.new(uri.host, uri.port)
-      request = Net::HTTP::Get.new(uri)
-      request["Host"] = "netcat"
-
-      http.request(request)
-    end
-end