Bootstrap JSON → code conversion in Go

internal/ast/builder.go

@@ -196,12 +196,15 @@ type PathItem struct {
 	// useful mostly for composability purposes, when a field Type is "any"
 	// and we're trying to "compose in" something of a known type.
 	TypeHint *Type `json:",omitempty"`
+	// Is this element of the path the root? (ie: a variable, not a member of a struct)
+	Root bool
 }
 
 func (item PathItem) DeepCopy() PathItem {
 	clone := PathItem{
 		Identifier: item.Identifier,
 		Type:       item.Type.DeepCopy(),
+		Root:       item.Root,
 	}
 
 	if item.TypeHint != nil {
@@ -241,6 +244,10 @@ func (path Path) Append(suffix Path) Path {
 	return newPath
 }
 
+func (path Path) AppendStructField(field StructField) Path {
+	return path.Append(PathFromStructField(field))
+}
+
 func (path Path) Last() PathItem {
 	return path[len(path)-1]
 }

internal/ast/types.go

@@ -514,6 +514,10 @@ func NewObject(pkg string, name string, objectType Type, passesTrail ...string)
 	}
 }
 
+func (object *Object) AsRef() Type {
+	return object.SelfRef.AsType()
+}
+
 func (object *Object) AddToPassesTrail(trail string) {
 	object.PassesTrail = append(object.PassesTrail, trail)
 }

internal/codegen/output.go

@@ -14,8 +14,9 @@ import (
 type Output struct {
 	Directory string `yaml:"directory"`
 
-	Types    bool `yaml:"types"`
-	Builders bool `yaml:"builders"`
+	Types      bool `yaml:"types"`
+	Builders   bool `yaml:"builders"`
+	Converters bool `yaml:"converters"`
 
 	Languages []*OutputLanguage `yaml:"languages"`
 

internal/codegen/pipeline.go

@@ -124,9 +124,10 @@ func (pipeline *Pipeline) interpolate(input string) string {
 
 func (pipeline *Pipeline) jenniesConfig() languages.Config {
 	return languages.Config{
-		Debug:    pipeline.Debug,
-		Types:    pipeline.Output.Types,
-		Builders: pipeline.Output.Builders,
+		Debug:      pipeline.Debug,
+		Types:      pipeline.Output.Types,
+		Builders:   pipeline.Output.Builders,
+		Converters: pipeline.Output.Converters,
 	}
 }
 

internal/jennies/golang/builder.go

@@ -18,6 +18,7 @@ type Builder struct {
 	Tmpl   *template.Template
 
 	typeImportMapper func(pkg string) string
+	pathFormatter    func(path ast.Path) string
 	typeFormatter    *typeFormatter
 }
 
@@ -55,6 +56,7 @@ func (jenny *Builder) generateBuilder(context languages.Context, builder ast.Bui
 		return imports.Add(pkg, jenny.Config.importPath(pkg))
 	}
 	jenny.typeFormatter = builderTypeFormatter(jenny.Config, context, jenny.typeImportMapper)
+	jenny.pathFormatter = makePathFormatter(jenny.typeFormatter)
 
 	// every builder has a dependency on cog's runtime, so let's make sure it's declared.
 	jenny.typeImportMapper("cog")
@@ -67,7 +69,7 @@ func (jenny *Builder) generateBuilder(context languages.Context, builder ast.Bui
 
 	return jenny.Tmpl.
 		Funcs(map[string]any{
-			"formatPath": jenny.formatFieldPath,
+			"formatPath": jenny.pathFormatter,
 			"formatType": jenny.typeFormatter.formatType,
 			"formatTypeNoBuilder": func(typeDef ast.Type) string {
 				return jenny.typeFormatter.doFormatType(typeDef, false)
@@ -171,28 +173,6 @@ func (jenny *Builder) formatDefaultTypedArgs(context languages.Context, opt ast.
 	return args
 }
 
-func (jenny *Builder) formatFieldPath(fieldPath ast.Path) string {
-	parts := make([]string, len(fieldPath))
-
-	for i := range fieldPath {
-		output := tools.UpperCamelCase(fieldPath[i].Identifier)
-
-		// don't generate type hints if:
-		// * there isn't one defined
-		// * the type isn't "any"
-		// * as a trailing element in the path
-		if !fieldPath[i].Type.IsAny() || fieldPath[i].TypeHint == nil || i == len(fieldPath)-1 {
-			parts[i] = output
-			continue
-		}
-
-		formattedTypeHint := jenny.typeFormatter.formatType(*fieldPath[i].TypeHint)
-		parts[i] = output + fmt.Sprintf(".(*%s)", formattedTypeHint)
-	}
-
-	return strings.Join(parts, ".")
-}
-
 func (jenny *Builder) emptyValueForType(typeDef ast.Type) string {
 	switch typeDef.Kind {
 	case ast.KindRef, ast.KindStruct, ast.KindArray, ast.KindMap:

internal/jennies/golang/converter.go

@@ -0,0 +1,77 @@
+package golang
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+
+	"github.com/grafana/codejen"
+	"github.com/grafana/cog/internal/ast"
+	"github.com/grafana/cog/internal/jennies/template"
+	"github.com/grafana/cog/internal/languages"
+)
+
+type Converter struct {
+	Config         Config
+	NullableConfig languages.NullableConfig
+	Tmpl           *template.Template
+}
+
+func (jenny *Converter) JennyName() string {
+	return "GoConverter"
+}
+
+func (jenny *Converter) Generate(context languages.Context) (codejen.Files, error) {
+	files := codejen.Files{}
+
+	for _, builder := range context.Builders {
+		output, err := jenny.generateConverter(context, builder)
+		if err != nil {
+			return nil, err
+		}
+
+		filename := filepath.Join(
+			formatPackageName(builder.Package),
+			fmt.Sprintf("%s_converter_gen.go", strings.ToLower(builder.Name)),
+		)
+
+		files = append(files, *codejen.NewFile(filename, output, jenny))
+	}
+
+	return files, nil
+}
+
+func (jenny *Converter) generateConverter(context languages.Context, builder ast.Builder) ([]byte, error) {
+	converter := languages.NewConverterGenerator(jenny.NullableConfig).FromBuilder(context, builder)
+
+	imports := NewImportMap()
+	typeImportMapper := func(pkg string) string {
+		if imports.IsIdentical(pkg, builder.Package) {
+			return ""
+		}
+
+		return imports.Add(pkg, jenny.Config.importPath(pkg))
+	}
+	typeImportMapper("cog")
+	formatter := builderTypeFormatter(jenny.Config, context, typeImportMapper)
+
+	dummyImports := NewImportMap()
+	dummyImportMapper := func(pkg string) string {
+		return dummyImports.Add(pkg, jenny.Config.importPath(pkg))
+	}
+
+	formatRawRef := func(pkg string, ref string) string {
+		return formatter.formatRef(ast.NewRef(pkg, ref), false)
+	}
+
+	return jenny.Tmpl.
+		Funcs(map[string]any{
+			"formatType":   builderTypeFormatter(jenny.Config, context, dummyImportMapper).formatType,
+			"formatPath":   makePathFormatter(formatter),
+			"formatRawRef": formatRawRef,
+		}).
+		RenderAsBytes("converters/converter.tmpl", map[string]any{
+			"Imports":   imports,
+			"Converter": converter,
+		})
+}

internal/jennies/golang/equality_test.go

@@ -117,25 +117,6 @@ func TestEquality_Struct_WithArrays(t *testing.T) {
 	req.True(equality.Arrays{Refs: []equality.Variable{}}.Equals(equality.Arrays{Refs: []equality.Variable{}}))
 	req.True(equality.Arrays{Refs: []equality.Variable{{Name: "foo"}}}.Equals(equality.Arrays{Refs: []equality.Variable{{Name: "foo"}}}))
 
-	req.True(equality.Arrays{AnonymousStructs: []struct {
-		Inner string `json:"inner"`
-	}{}}.Equals(equality.Arrays{
-		AnonymousStructs: []struct {
-			Inner string `json:"inner"`
-		}{},
-	}))
-	req.True(equality.Arrays{AnonymousStructs: []struct {
-		Inner string `json:"inner"`
-	}{
-		{Inner: "foo"},
-	}}.Equals(equality.Arrays{
-		AnonymousStructs: []struct {
-			Inner string `json:"inner"`
-		}{
-			{Inner: "foo"},
-		},
-	}))
-
 	req.True(equality.Arrays{ArrayOfAny: []any{}}.Equals(equality.Arrays{ArrayOfAny: []any{}}))
 	req.True(equality.Arrays{ArrayOfAny: []any{"foo", 1}}.Equals(equality.Arrays{ArrayOfAny: []any{"foo", 1}}))
 
@@ -146,30 +127,6 @@ func TestEquality_Struct_WithArrays(t *testing.T) {
 	req.False(equality.Arrays{ArrayOfArray: [][]string{{"foo"}, {"bar"}}}.Equals(equality.Arrays{ArrayOfArray: [][]string{{"foo"}}}))
 	req.False(equality.Arrays{ArrayOfArray: [][]string{{"foo"}, {"bar"}}}.Equals(equality.Arrays{ArrayOfArray: [][]string{{"foo"}, {"other"}}}))
 
-	req.False(equality.Arrays{AnonymousStructs: []struct {
-		Inner string `json:"inner"`
-	}{
-		{Inner: "foo"},
-	}}.Equals(equality.Arrays{
-		AnonymousStructs: []struct {
-			Inner string `json:"inner"`
-		}{
-			{Inner: "bar"},
-		},
-	}))
-	req.False(equality.Arrays{AnonymousStructs: []struct {
-		Inner string `json:"inner"`
-	}{
-		{Inner: "foo"},
-	}}.Equals(equality.Arrays{
-		AnonymousStructs: []struct {
-			Inner string `json:"inner"`
-		}{
-			{Inner: "foo"},
-			{Inner: "bar"},
-		},
-	}))
-
 	req.False(equality.Arrays{ArrayOfAny: []any{"foo", 1}}.Equals(equality.Arrays{ArrayOfAny: []any{"foo"}}))
 	req.False(equality.Arrays{ArrayOfAny: []any{"bar"}}.Equals(equality.Arrays{ArrayOfAny: []any{"foo"}}))
 }
@@ -200,19 +157,6 @@ func TestEquality_Struct_WithMaps(t *testing.T) {
 			"foo": {Name: "foo"},
 		},
 	}))
-	req.True(equality.Maps{
-		AnonymousStructs: map[string]struct {
-			Inner string `json:"inner"`
-		}{
-			"foo": {Inner: "foo"},
-		},
-	}.Equals(equality.Maps{
-		AnonymousStructs: map[string]struct {
-			Inner string `json:"inner"`
-		}{
-			"foo": {Inner: "foo"},
-		},
-	}))
 	req.True(equality.Maps{
 		StringToAny: map[string]any{
 			"foo": 42,

internal/jennies/golang/jennies.go

@@ -15,8 +15,9 @@ import (
 const LanguageRef = "go"
 
 type Config struct {
-	debug            bool
-	generateBuilders bool
+	debug              bool
+	generateBuilders   bool
+	generateConverters bool
 
 	// GenerateGoMod indicates whether a go.mod file should be generated.
 	// If enabled, PackageRoot is used as module path.
@@ -45,6 +46,7 @@ func (config Config) MergeWithGlobal(global languages.Config) Config {
 	newConfig := config
 	newConfig.debug = global.Debug
 	newConfig.generateBuilders = global.Builders
+	newConfig.generateConverters = global.Converters
 
 	return newConfig
 }
@@ -85,6 +87,7 @@ func (language *Language) Jennies(globalConfig languages.Config) *codejen.JennyL
 		common.If[languages.Context](globalConfig.Types, RawTypes{Config: config, Tmpl: tmpl}),
 
 		common.If[languages.Context](!config.SkipRuntime && globalConfig.Builders, &Builder{Config: config, Tmpl: tmpl}),
+		common.If[languages.Context](!config.SkipRuntime && globalConfig.Builders && globalConfig.Converters, &Converter{Config: config, Tmpl: tmpl, NullableConfig: language.NullableKinds()}),
 	)
 	jenny.AddPostprocessors(PostProcessFile, common.GeneratedCommentHeader(globalConfig))
 
@@ -94,6 +97,7 @@ func (language *Language) Jennies(globalConfig languages.Config) *codejen.JennyL
 func (language *Language) CompilerPasses() compiler.Passes {
 	return compiler.Passes{
 		&compiler.AnonymousEnumToExplicitType{},
+		&compiler.AnonymousStructsToNamed{},
 		&compiler.PrefixEnumValues{},
 		&compiler.NotRequiredFieldAsNullableType{},
 		&compiler.FlattenDisjunctions{},

internal/jennies/golang/jsonmarshalling.go

@@ -12,12 +12,14 @@ import (
 
 type JSONMarshalling struct {
 	tmpl          *template.Template
+	config        Config
 	packageMapper func(string) string
 	typeFormatter *typeFormatter
 }
 
-func NewJSONMarshalling(tmpl *template.Template, packageMapper func(string) string, typeFormatter *typeFormatter) JSONMarshalling {
+func NewJSONMarshalling(config Config, tmpl *template.Template, packageMapper func(string) string, typeFormatter *typeFormatter) JSONMarshalling {
 	return JSONMarshalling{
+		config: config,
 		tmpl: tmpl.Funcs(template.FuncMap{
 			"formatType": typeFormatter.formatType,
 		}),
@@ -301,18 +303,34 @@ func (jenny JSONMarshalling) renderPanelcfgVariantUnmarshal(schema *ast.Schema)
 	_, hasOptions := schema.LocateObject("Options")
 	_, hasFieldConfig := schema.LocateObject("FieldConfig")
 
+	if jenny.config.generateConverters {
+		jenny.packageMapper("dashboard")
+	}
+
 	return jenny.tmpl.Render("types/variant_panelcfg.json_unmarshal.tmpl", map[string]any{
 		"schema":         schema,
 		"hasOptions":     hasOptions,
 		"hasFieldConfig": hasFieldConfig,
+		"hasConverter":   jenny.config.generateConverters,
 	})
 }
 
 func (jenny JSONMarshalling) renderDataqueryVariantUnmarshal(schema *ast.Schema, obj ast.Object) (string, error) {
 	jenny.packageMapper("cog/variants")
 
+	var disjunctionStruct *ast.StructType
+
+	if obj.Type.IsRef() {
+		resolved, _ := schema.Resolve(obj.Type)
+		if resolved.IsStructGeneratedFromDisjunction() {
+			disjunctionStruct = resolved.Struct
+		}
+	}
+
 	return jenny.tmpl.Render("types/variant_dataquery.json_unmarshal.tmpl", map[string]any{
-		"schema": schema,
-		"object": obj,
+		"schema":            schema,
+		"object":            obj,
+		"hasConverter":      jenny.config.generateConverters,
+		"disjunctionStruct": disjunctionStruct,
 	})
 }

internal/jennies/golang/rawtypes.go

@@ -56,7 +56,7 @@ func (jenny RawTypes) generateSchema(context languages.Context, schema *ast.Sche
 		return imports.Add(pkg, jenny.Config.importPath(pkg))
 	}
 	jenny.typeFormatter = defaultTypeFormatter(jenny.Config, context, packageMapper)
-	unmarshallerGenerator := NewJSONMarshalling(jenny.Tmpl, packageMapper, jenny.typeFormatter)
+	unmarshallerGenerator := NewJSONMarshalling(jenny.Config, jenny.Tmpl, packageMapper, jenny.typeFormatter)
 	equalityMethodsGenerator := newEqualityMethods(jenny.Tmpl)
 
 	schema.Objects.Iterate(func(_ string, object ast.Object) {

internal/jennies/golang/runtime.go

@@ -106,6 +106,14 @@ func MakeBuildErrors(rootPath string, err error) BuildErrors {
 	}}
 }
 
+func Unptr[T any](v *T) T {
+	var val T
+	if v == nil {
+		return val
+	}
+	return *v
+}
+
 `)
 }