Allow configuring the federation output file location

api/generate.go

@@ -23,7 +23,7 @@ func Generate(cfg *config.Config, option ...Option) error {
 		plugins = append(plugins, modelgen.New())
 	}
 	plugins = append(plugins, resolvergen.New())
-	if cfg.Federated {
+	if cfg.Federation.IsDefined() {
 		plugins = append([]plugin.Plugin{federation.New()}, plugins...)
 	}
 

cmd/init.go

@@ -26,6 +26,11 @@ exec:
   filename: graph/generated/generated.go
   package: generated
 
+# Uncomment to enable federation
+# federation:
+#   filename: graph/generated/federation.go
+#   package: generated
+
 # Where should any generated models go?
 model:
   filename: graph/model/models_gen.go

codegen/config/config.go

@@ -20,17 +20,20 @@ type Config struct {
 	SchemaFilename           StringList                 `yaml:"schema,omitempty"`
 	Exec                     PackageConfig              `yaml:"exec"`
 	Model                    PackageConfig              `yaml:"model,omitempty"`
+	Federation               PackageConfig              `yaml:"federation,omitempty"`
 	Resolver                 ResolverConfig             `yaml:"resolver,omitempty"`
 	AutoBind                 []string                   `yaml:"autobind"`
 	Models                   TypeMap                    `yaml:"models,omitempty"`
 	StructTag                string                     `yaml:"struct_tag,omitempty"`
 	Directives               map[string]DirectiveConfig `yaml:"directives,omitempty"`
 	OmitSliceElementPointers bool                       `yaml:"omit_slice_element_pointers,omitempty"`
 	SkipValidation           bool                       `yaml:"skip_validation,omitempty"`
-	Federated                bool                       `yaml:"federated,omitempty"`
 	AdditionalSources        []*ast.Source              `yaml:"-"`
 	Packages                 *code.Packages             `yaml:"-"`
 	Schema                   *ast.Schema                `yaml:"-"`
+
+	// Deprecated use Federation instead. Will be removed next release
+	Federated bool `yaml:"federated,omitempty"`
 }
 
 var cfgFilenames = []string{".gqlgen.yml", "gqlgen.yml", "gqlgen.yaml"}
@@ -330,6 +333,22 @@ func (c *Config) check() error {
 			Declaree: "resolver",
 		})
 	}
+	if c.Federation.IsDefined() {
+		if err := c.Federation.Check(); err != nil {
+			return errors.Wrap(err, "config.federation")
+		}
+		fileList[c.Federation.ImportPath()] = append(fileList[c.Federation.ImportPath()], FilenamePackage{
+			Filename: c.Federation.Filename,
+			Package:  c.Federation.Package,
+			Declaree: "federation",
+		})
+		if c.Federation.ImportPath() != c.Exec.ImportPath() {
+			return fmt.Errorf("federation and exec must be in the same package")
+		}
+	}
+	if c.Federated {
+		return fmt.Errorf("federated has been removed, instead use\nfederation:\n    filename: path/to/federated.go")
+	}
 
 	for importPath, pkg := range fileList {
 		for _, file1 := range pkg {

codegen/config/config_test.go

@@ -108,11 +108,39 @@ func TestReferencedPackages(t *testing.T) {
 
 func TestConfigCheck(t *testing.T) {
 	t.Run("invalid config format due to conflicting package names", func(t *testing.T) {
-		config, err := LoadConfig("testdata/cfg/conflictedPackages.yml")
-		require.NoError(t, err)
+		config := Config{
+			Exec:  PackageConfig{Filename: "generated/exec.go", Package: "graphql"},
+			Model: PackageConfig{Filename: "generated/models.go"},
+		}
+
+		require.EqualError(t, config.check(), "exec and model define the same import path (github.com/99designs/gqlgen/codegen/config/generated) with different package names (graphql vs generated)")
+	})
+
+	t.Run("federation must be in exec package", func(t *testing.T) {
+		config := Config{
+			Exec:       PackageConfig{Filename: "generated/exec.go"},
+			Federation: PackageConfig{Filename: "anotherpkg/federation.go"},
+		}
+
+		require.EqualError(t, config.check(), "federation and exec must be in the same package")
+	})
+
+	t.Run("federation must have same package name as exec", func(t *testing.T) {
+		config := Config{
+			Exec:       PackageConfig{Filename: "generated/exec.go"},
+			Federation: PackageConfig{Filename: "generated/federation.go", Package: "federation"},
+		}
+
+		require.EqualError(t, config.check(), "exec and federation define the same import path (github.com/99designs/gqlgen/codegen/config/generated) with different package names (generated vs federation)")
+	})
+
+	t.Run("deprecated federated flag raises an error", func(t *testing.T) {
+		config := Config{
+			Exec:      PackageConfig{Filename: "generated/exec.go"},
+			Federated: true,
+		}
 
-		err = config.check()
-		require.EqualError(t, err, "exec and model define the same import path (github.com/99designs/gqlgen/codegen/config/generated) with different package names (graphql vs generated)")
+		require.EqualError(t, config.check(), "federated has been removed, instead use\nfederation:\n    filename: path/to/federated.go")
 	})
 }
 

docs/content/config.md

@@ -20,6 +20,11 @@ exec:
   filename: graph/generated/generated.go
   package: generated
 
+# Enable Apollo federation support
+federation:
+  filename: graph/generated/federation.go
+  package: generated
+
 # Where should any generated models go?
 model:
   filename: graph/model/models_gen.go

plugin/federation/federation.go

@@ -240,8 +240,8 @@ func (f *federation) GenerateCode(data *codegen.Data) error {
 	}
 
 	return templates.Render(templates.Options{
-		PackageName:     data.Config.Exec.Package,
-		Filename:        "service.go",
+		PackageName:     data.Config.Federation.Package,
+		Filename:        data.Config.Federation.Filename,
 		Data:            f,
 		GeneratedHeader: true,
 		Packages:        data.Config.Packages,

plugin/federation/test_data/gqlgen.yml

@@ -1,3 +1,6 @@
 schema:
   - "test_data/schema.graphql"
-federated: true
+exec:
+  filename: graph/generated/exec.go
+federation:
+  filename: graph/generated/federation.go

plugin/federation/test_data/nokey.yml

@@ -1,3 +1,6 @@
 schema:
   - "test_data/nokey.graphql"
-federated: true
+exec:
+  filename: graph/generated/exec.go
+federation:
+  filename: graph/generated/federation.go