Configuration validation

Validate the Kamal configuration giving useful warning on errors.
Each section of the configuration has its own config class and a YAML
file containing documented example configuration.

You can run `kamal docs` to see the example configuration, and
`kamal docs <section>` to see the example configuration for a specific
section.

The validation matches the configuration to the example configuration
checking that there are no unknown keys and that the values are of
matching types.

Where there is more complex validation - e.g for envs and servers, we
have custom validators that implement those rules.

Additonally the configuration examples are used to generate the
configuration documentation in the kamal-site repo.

You generate them by running:

```
bundle exec bin/docs <kamal-site-checkout>
```

test/configuration/builder_test.rb

@@ -7,41 +7,37 @@ class ConfigurationBuilderTest < ActiveSupport::TestCase
       servers: [ "1.1.1.1" ]
     }
 
-    @config = Kamal::Configuration.new(@deploy)
-
     @deploy_with_builder_option = {
       service: "app", image: "dhh/app", registry: { "username" => "dhh", "password" => "secret" },
       servers: [ "1.1.1.1" ],
       builder: {}
     }
-
-    @config_with_builder_option = Kamal::Configuration.new(@deploy_with_builder_option)
   end
 
   test "multiarch?" do
-    assert_equal true, @config.builder.multiarch?
+    assert_equal true, config.builder.multiarch?
   end
 
   test "setting multiarch to false" do
     @deploy_with_builder_option[:builder] = { "multiarch" => false }
 
-    assert_equal false, @config_with_builder_option.builder.multiarch?
+    assert_equal false, config_with_builder_option.builder.multiarch?
   end
 
   test "local?" do
-    assert_equal false, @config.builder.local?
+    assert_equal false, config.builder.local?
   end
 
   test "remote?" do
-    assert_equal false, @config.builder.remote?
+    assert_equal false, config.builder.remote?
   end
 
   test "remote_arch" do
-    assert_nil @config.builder.remote_arch
+    assert_nil config.builder.remote_arch
   end
 
   test "remote_host" do
-    assert_nil @config.builder.remote_host
+    assert_nil config.builder.remote_host
   end
 
   test "setting both local and remote configs" do
@@ -50,112 +46,121 @@ class ConfigurationBuilderTest < ActiveSupport::TestCase
       "remote" => { "arch" => "amd64", "host" => "ssh://root@192.168.0.1" }
     }
 
-    assert_equal true, @config_with_builder_option.builder.local?
-    assert_equal true, @config_with_builder_option.builder.remote?
+    assert_equal true, config_with_builder_option.builder.local?
+    assert_equal true, config_with_builder_option.builder.remote?
 
-    assert_equal "amd64", @config_with_builder_option.builder.remote_arch
-    assert_equal "ssh://root@192.168.0.1", @config_with_builder_option.builder.remote_host
+    assert_equal "amd64", config_with_builder_option.builder.remote_arch
+    assert_equal "ssh://root@192.168.0.1", config_with_builder_option.builder.remote_host
 
-    assert_equal "arm64", @config_with_builder_option.builder.local_arch
-    assert_equal "unix:///Users/<%= `whoami`.strip %>/.docker/run/docker.sock", @config_with_builder_option.builder.local_host
+    assert_equal "arm64", config_with_builder_option.builder.local_arch
+    assert_equal "unix:///Users/<%= `whoami`.strip %>/.docker/run/docker.sock", config_with_builder_option.builder.local_host
   end
 
   test "cached?" do
-    assert_equal false, @config.builder.cached?
+    assert_equal false, config.builder.cached?
   end
 
   test "invalid cache type specified" do
     @deploy_with_builder_option[:builder] = { "cache" => { "type" => "invalid" } }
 
-    assert_raises(ArgumentError) do
-      @config_with_builder_option.builder
+    assert_raises(Kamal::ConfigurationError) do
+      config_with_builder_option.builder
     end
   end
 
   test "cache_from" do
-    assert_nil @config.builder.cache_from
+    assert_nil config.builder.cache_from
   end
 
   test "cache_to" do
-    assert_nil @config.builder.cache_to
+    assert_nil config.builder.cache_to
   end
 
   test "setting gha cache" do
     @deploy_with_builder_option[:builder] = { "cache" => { "type" => "gha", "options" => "mode=max" } }
 
-    assert_equal "type=gha", @config_with_builder_option.builder.cache_from
-    assert_equal "type=gha,mode=max", @config_with_builder_option.builder.cache_to
+    assert_equal "type=gha", config_with_builder_option.builder.cache_from
+    assert_equal "type=gha,mode=max", config_with_builder_option.builder.cache_to
   end
 
   test "setting registry cache" do
     @deploy_with_builder_option[:builder] = { "cache" => { "type" => "registry", "options" => "mode=max,image-manifest=true,oci-mediatypes=true" } }
 
-    assert_equal "type=registry,ref=dhh/app-build-cache", @config_with_builder_option.builder.cache_from
-    assert_equal "type=registry,mode=max,image-manifest=true,oci-mediatypes=true,ref=dhh/app-build-cache", @config_with_builder_option.builder.cache_to
+    assert_equal "type=registry,ref=dhh/app-build-cache", config_with_builder_option.builder.cache_from
+    assert_equal "type=registry,mode=max,image-manifest=true,oci-mediatypes=true,ref=dhh/app-build-cache", config_with_builder_option.builder.cache_to
   end
 
   test "setting registry cache when using a custom registry" do
-    @config_with_builder_option.registry["server"] = "registry.example.com"
+    @deploy_with_builder_option[:registry]["server"] = "registry.example.com"
     @deploy_with_builder_option[:builder] = { "cache" => { "type" => "registry", "options" => "mode=max,image-manifest=true,oci-mediatypes=true" } }
 
-    assert_equal "type=registry,ref=registry.example.com/dhh/app-build-cache", @config_with_builder_option.builder.cache_from
-    assert_equal "type=registry,mode=max,image-manifest=true,oci-mediatypes=true,ref=registry.example.com/dhh/app-build-cache", @config_with_builder_option.builder.cache_to
+    assert_equal "type=registry,ref=registry.example.com/dhh/app-build-cache", config_with_builder_option.builder.cache_from
+    assert_equal "type=registry,mode=max,image-manifest=true,oci-mediatypes=true,ref=registry.example.com/dhh/app-build-cache", config_with_builder_option.builder.cache_to
   end
 
   test "setting registry cache with image" do
     @deploy_with_builder_option[:builder] = { "cache" => { "type" => "registry", "image" => "kamal", "options" => "mode=max" } }
 
-    assert_equal "type=registry,ref=kamal", @config_with_builder_option.builder.cache_from
-    assert_equal "type=registry,mode=max,ref=kamal", @config_with_builder_option.builder.cache_to
+    assert_equal "type=registry,ref=kamal", config_with_builder_option.builder.cache_from
+    assert_equal "type=registry,mode=max,ref=kamal", config_with_builder_option.builder.cache_to
   end
 
   test "args" do
-    assert_equal({}, @config.builder.args)
+    assert_equal({}, config.builder.args)
   end
 
   test "setting args" do
     @deploy_with_builder_option[:builder] = { "args" => { "key" => "value" } }
 
-    assert_equal({ "key" => "value" }, @config_with_builder_option.builder.args)
+    assert_equal({ "key" => "value" }, config_with_builder_option.builder.args)
   end
 
   test "secrets" do
-    assert_equal [], @config.builder.secrets
+    assert_equal [], config.builder.secrets
   end
 
   test "setting secrets" do
     @deploy_with_builder_option[:builder] = { "secrets" => [ "GITHUB_TOKEN" ] }
 
-    assert_equal [ "GITHUB_TOKEN" ], @config_with_builder_option.builder.secrets
+    assert_equal [ "GITHUB_TOKEN" ], config_with_builder_option.builder.secrets
   end
 
   test "dockerfile" do
-    assert_equal "Dockerfile", @config.builder.dockerfile
+    assert_equal "Dockerfile", config.builder.dockerfile
   end
 
   test "setting dockerfile" do
     @deploy_with_builder_option[:builder] = { "dockerfile" => "Dockerfile.dev" }
 
-    assert_equal "Dockerfile.dev", @config_with_builder_option.builder.dockerfile
+    assert_equal "Dockerfile.dev", config_with_builder_option.builder.dockerfile
   end
 
   test "context" do
-    assert_equal ".", @config.builder.context
+    assert_equal ".", config.builder.context
   end
 
   test "setting context" do
     @deploy_with_builder_option[:builder] = { "context" => ".." }
 
-    assert_equal "..", @config_with_builder_option.builder.context
+    assert_equal "..", config_with_builder_option.builder.context
   end
 
   test "ssh" do
-    assert_nil @config.builder.ssh
+    assert_nil config.builder.ssh
   end
 
   test "setting ssh params" do
     @deploy_with_builder_option[:builder] = { "ssh" => "default=$SSH_AUTH_SOCK" }
 
-    assert_equal "default=$SSH_AUTH_SOCK", @config_with_builder_option.builder.ssh
+    assert_equal "default=$SSH_AUTH_SOCK", config_with_builder_option.builder.ssh
   end
+
+  private
+    def config
+      Kamal::Configuration.new(@deploy)
+    end
+
+    def config_with_builder_option
+      Kamal::Configuration.new(@deploy_with_builder_option)
+    end
 end