cmd: import twirp-openapi-gen, fix some bugs

Signed-off-by: Xe Iaso <me@xeiaso.net>

15 files changed, 5471 insertions, 0 deletions

diff --git a/cmd/twirp-openapi-gen/LICENSE b/cmd/twirp-openapi-gen/LICENSE
new file mode 100644
index 0000000..261eeb9
--- /dev/null
+++ b/cmd/twirp-openapi-gen/LICENSE
@@ -0,0 +1,201 @@
+                                 Apache License
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+                        http://www.apache.org/licenses/
+
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diff --git a/cmd/twirp-openapi-gen/README.md b/cmd/twirp-openapi-gen/README.md
new file mode 100644
index 0000000..d3bf9a8
--- /dev/null
+++ b/cmd/twirp-openapi-gen/README.md
@@ -0,0 +1,3 @@
+# twirp-openapi-gen
+
+This was imported from [github.com/blockthrough/twirp-openapi-gen](https://github.com/blockthrough/twirp-openapi-gen) and a few non-upstreamable changes were made. These changes are made in order to meet my needs in particular. If you want to use this tool, I recommend you to use the original repository.
diff --git a/cmd/twirp-openapi-gen/internal/generator/aliases.go b/cmd/twirp-openapi-gen/internal/generator/aliases.go
new file mode 100644
index 0000000..a8e29f3
--- /dev/null
+++ b/cmd/twirp-openapi-gen/internal/generator/aliases.go
@@ -0,0 +1,85 @@
+package generator
+
+var typeAliases = map[string]struct {
+	Type, Format string
+}{
+	// proto numeric types
+	"int32":    {Type: "integer", Format: "int32"},
+	"uint32":   {Type: "integer", Format: "uint32"},
+	"sint32":   {Type: "integer", Format: "int32"},
+	"fixed32":  {Type: "integer", Format: "int32"},
+	"sfixed32": {Type: "integer", Format: "int32"},
+
+	// proto numeric types, 64bit
+	"int64":    {Type: "string", Format: "int64"},
+	"uint64":   {Type: "string", Format: "uint64"},
+	"sint64":   {Type: "string", Format: "int64"},
+	"fixed64":  {Type: "string", Format: "int64"},
+	"sfixed64": {Type: "string", Format: "int64"},
+
+	"double": {Type: "number", Format: "double"},
+	"float":  {Type: "number", Format: "float"},
+
+	// effectively copies google.protobuf.BytesValue
+	"bytes": {
+		Type:   "string",
+		Format: "byte",
+	},
+
+	// It is what it is
+	"bool": {
+		Type:   "boolean",
+		Format: "boolean",
+	},
+
+	"google.protobuf.Timestamp": {
+		Type:   "string",
+		Format: "date-time",
+	},
+	"google.protobuf.Duration": {
+		Type: "string",
+	},
+	"google.protobuf.StringValue": {
+		Type: "string",
+	},
+	"google.protobuf.BytesValue": {
+		Type:   "string",
+		Format: "byte",
+	},
+	"google.protobuf.Int32Value": {
+		Type:   "integer",
+		Format: "int32",
+	},
+	"google.protobuf.UInt32Value": {
+		Type:   "integer",
+		Format: "uint32",
+	},
+	"google.protobuf.Int64Value": {
+		Type:   "string",
+		Format: "int64",
+	},
+	"google.protobuf.UInt64Value": {
+		Type:   "string",
+		Format: "uint64",
+	},
+	"google.protobuf.FloatValue": {
+		Type:   "number",
+		Format: "float",
+	},
+	"google.protobuf.DoubleValue": {
+		Type:   "number",
+		Format: "double",
+	},
+	"google.protobuf.BoolValue": {
+		Type:   "boolean",
+		Format: "boolean",
+	},
+	"google.protobuf.Empty": {
+		Type: "object",
+	},
+
+	"google.type.DateTime": {
+		Type:   "string",
+		Format: "date-time",
+	},
+}
diff --git a/cmd/twirp-openapi-gen/internal/generator/generator.go b/cmd/twirp-openapi-gen/internal/generator/generator.go
new file mode 100644
index 0000000..2a08055
--- /dev/null
+++ b/cmd/twirp-openapi-gen/internal/generator/generator.go
@@ -0,0 +1,187 @@
+package generator
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"os"
+	"path/filepath"
+
+	"github.com/emicklei/proto"
+	"github.com/getkin/kin-openapi/openapi3"
+	"github.com/invopop/yaml"
+)
+
+type generatorConfig struct {
+	protoPaths []string
+	servers    []string
+	title      string
+	docVersion string
+	pathPrefix string
+	format     string
+}
+
+type Option func(config *generatorConfig) error
+
+func ProtoPaths(paths []string) Option {
+	return func(config *generatorConfig) error {
+		config.protoPaths = paths
+		return nil
+	}
+}
+
+func Servers(servers []string) Option {
+	return func(config *generatorConfig) error {
+		config.servers = servers
+		return nil
+	}
+}
+
+func Title(title string) Option {
+	return func(config *generatorConfig) error {
+		config.title = title
+		return nil
+	}
+}
+
+func DocVersion(version string) Option {
+	return func(config *generatorConfig) error {
+		config.docVersion = version
+		return nil
+	}
+}
+
+func PathPrefix(pathPrefix string) Option {
+	return func(config *generatorConfig) error {
+		config.pathPrefix = pathPrefix
+		return nil
+	}
+}
+
+func Format(format string) Option {
+	return func(config *generatorConfig) error {
+		config.format = format
+		return nil
+	}
+}
+
+type generator struct {
+	openAPIV3 *openapi3.T
+
+	conf        *generatorConfig
+	inputFiles  []string
+	packageName string
+
+	importedFiles map[string]struct{}
+}
+
+func NewGenerator(inputFiles []string, options ...Option) (*generator, error) {
+	conf := generatorConfig{}
+	for _, opt := range options {
+		if err := opt(&conf); err != nil {
+			return nil, err
+		}
+	}
+
+	if len(inputFiles) < 1 {
+		return nil, fmt.Errorf("missing input files")
+	}
+
+	openAPIV3 := openapi3.T{
+		OpenAPI: "3.0.0",
+		Info: &openapi3.Info{
+			Title:   conf.title,
+			Version: conf.docVersion,
+		},
+		Paths: openapi3.Paths{},
+		Components: &openapi3.Components{
+			Schemas: map[string]*openapi3.SchemaRef{},
+		},
+	}
+
+	for _, server := range conf.servers {
+		openAPIV3.Servers = append(openAPIV3.Servers, &openapi3.Server{URL: server})
+	}
+
+	slog.Debug("generating doc", "format", conf.format, "inputFiles", inputFiles)
+
+	return &generator{
+		inputFiles:    inputFiles,
+		openAPIV3:     &openAPIV3,
+		conf:          &conf,
+		importedFiles: map[string]struct{}{},
+	}, nil
+}
+
+func (gen *generator) Generate(filename string) error {
+	if _, err := gen.Parse(); err != nil {
+		return err
+	}
+
+	if err := gen.Save(filename); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (gen *generator) Parse() (*openapi3.T, error) {
+	for _, filename := range gen.inputFiles {
+		protoFile, err := readProtoFile(filename, gen.conf.protoPaths)
+		if err != nil {
+			return nil, fmt.Errorf("readProtoFile: %w", err)
+		}
+		proto.Walk(protoFile, gen.Handlers()...)
+	}
+
+	slog.Debug("generated", "paths", len(gen.openAPIV3.Paths), "components", len(gen.openAPIV3.Components.Schemas))
+	return gen.openAPIV3, nil
+}
+
+func (gen *generator) Save(filename string) error {
+	var by []byte
+	var err error
+	switch gen.conf.format {
+	case "json":
+		by, err = gen.JSON()
+	case "yaml", "yml":
+		by, err = gen.YAML()
+	default:
+		return fmt.Errorf("missing format")
+	}
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(filename, by, os.ModePerm^0111)
+}
+
+func (gen *generator) JSON() ([]byte, error) {
+	return json.MarshalIndent(gen.openAPIV3, "", "  ")
+}
+
+func (gen *generator) YAML() ([]byte, error) {
+	return yaml.Marshal(gen.openAPIV3)
+}
+
+func readProtoFile(filename string, protoPaths []string) (*proto.Proto, error) {
+	var file *os.File
+	var err error
+	for _, path := range append(protoPaths, "") {
+		file, err = os.Open(filepath.Join(path, filename))
+		if err != nil {
+			if os.IsNotExist(err) {
+				continue
+			}
+			return nil, fmt.Errorf("Open: %w", err)
+		}
+		break
+	}
+	if file == nil {
+		return nil, fmt.Errorf("could not read file %q", filename)
+	}
+	defer file.Close()
+
+	parser := proto.NewParser(file)
+	return parser.Parse()
+}
diff --git a/cmd/twirp-openapi-gen/internal/generator/generator_test.go b/cmd/twirp-openapi-gen/internal/generator/generator_test.go
new file mode 100644
index 0000000..78af950
--- /dev/null
+++ b/cmd/twirp-openapi-gen/internal/generator/generator_test.go
@@ -0,0 +1,317 @@
+package generator
+
+import (
+	"flag"
+	"log/slog"
+	"os"
+	"strings"
+	"testing"
+)
+
+type ProtoRPC struct {
+	name   string
+	input  string
+	output string
+	desc   string
+}
+
+type ProtoMessage struct {
+	name   string
+	fields []ProtoField
+}
+
+type ProtoField struct {
+	name      string
+	fieldType string
+	format    string
+	desc      string
+	enums     []string
+	ref       string
+	itemsRef  string
+	itemsType string
+}
+
+var (
+	verbose = flag.Bool("slog.verbose", false, "print debug logs to the console")
+)
+
+func init() {
+	if *verbose {
+		h := slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{
+			AddSource: true,
+			Level:     slog.LevelDebug,
+		})
+		slog.SetDefault(slog.New(h))
+	} else {
+		slog.SetDefault(slog.New(slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{
+			AddSource: true,
+		})))
+	}
+}
+
+func TestGenerator(t *testing.T) {
+	flag.Parse()
+
+	opts := []Option{
+		ProtoPaths([]string{"./testdata/paymentapis", "./testdata/petapis"}),
+		Servers([]string{"https://example.com"}),
+		Title("Test"),
+		DocVersion("0.1"),
+		Format("json"),
+	}
+	gen, err := NewGenerator([]string{"./testdata/petapis/pet/v1/pet.proto"}, opts...)
+	if err != nil {
+		t.Fatal(err)
+	}
+	openAPI, err := gen.Parse()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err := gen.Save("./testdata/doc.json"); err != nil {
+		t.Fatal(err)
+	}
+
+	pkgName := "pet.v1"
+	serviceName := "PetStoreService"
+	rpcs := []ProtoRPC{
+		{
+			name:   "GetPet",
+			input:  "GetPetRequest",
+			output: "GetPetResponse",
+		},
+	}
+	messages := []ProtoMessage{
+		{
+			name: "GetPetRequest",
+			fields: []ProtoField{
+				{
+					name:      "pet_id",
+					fieldType: "string",
+				},
+			},
+		},
+		{
+			name: "Pet",
+			fields: []ProtoField{
+				{
+					name:      "pet_type",
+					fieldType: "object",
+					ref:       "#/components/schemas/pet.v1.PetType",
+					enums: []string{
+						"PET_TYPE_UNSPECIFIED",
+						"PET_TYPE_CAT",
+						"PET_TYPE_DOG",
+						"PET_TYPE_SNAKE",
+						"PET_TYPE_HAMSTER",
+					},
+				},
+				{
+					name:      "pet_types",
+					fieldType: "array",
+					itemsRef:  "#/components/schemas/pet.v1.PetType",
+				},
+				{
+					name:      "tags",
+					fieldType: "array",
+					itemsType: "string",
+				},
+				{
+					name:      "pet_id",
+					fieldType: "string",
+					desc:      "pet_id is an auto-generated id for the pet\\nthe id uniquely identifies a pet in the system",
+				},
+				{
+					name:      "name",
+					fieldType: "string",
+				},
+				{
+					name:      "created_at",
+					fieldType: "string",
+					format:    "date-time",
+				},
+				{
+					name:      "vet",
+					fieldType: "object",
+					ref:       "#/components/schemas/pet.v1.Vet",
+				},
+				{
+					name:      "vets",
+					fieldType: "array",
+					itemsRef:  "#/components/schemas/pet.v1.Vet",
+					itemsType: "object",
+				},
+			},
+		},
+	}
+
+	t.Run("RPC", func(t *testing.T) {
+		for _, rpc := range rpcs {
+			pathName := "/" + pkgName + "." + serviceName + "/" + rpc.name
+			path, ok := openAPI.Paths[pathName]
+			if !ok {
+				t.Errorf("%s: missing rpc %q", pathName, rpc.name)
+			}
+
+			if path.Description != rpc.desc {
+				t.Errorf("%s: expected desc %q but got %q", pathName, rpc.desc, path.Description)
+			}
+
+			post := path.Post
+			if post == nil {
+				t.Errorf("%s: missing post", pathName)
+				continue
+			}
+
+			if post.Summary != rpc.name {
+				t.Errorf("%s: expected summary %q but got %q", pathName, rpc.name, post.Summary)
+			}
+
+			requestBodyRef := post.RequestBody
+			if requestBodyRef == nil {
+				t.Errorf("%s: missing request body", pathName)
+				continue
+			}
+
+			// request
+			{
+				requestBody := requestBodyRef.Value
+				if requestBody == nil {
+					t.Errorf("%s: missing request body", pathName)
+					continue
+				}
+
+				mediaType, ok := requestBody.Content["application/json"]
+				if !ok {
+					t.Errorf("%s: missing content type", pathName)
+					continue
+				}
+
+				if mediaType.Schema == nil {
+					t.Errorf("%s: missing media type schema", pathName)
+					continue
+				}
+
+				expectedRef := "#/components/schemas/" + pkgName + "." + rpc.input
+				if mediaType.Schema.Ref != expectedRef {
+					t.Errorf("%s: expected ref %q but got %q", pathName, expectedRef, mediaType.Schema.Ref)
+				}
+			}
+
+			// response
+			{
+				respRef := post.Responses["200"]
+				if respRef == nil {
+					t.Errorf("%s: missing resp", pathName)
+					continue
+				}
+
+				resp := respRef.Value
+				if resp == nil {
+					t.Errorf("%s: missing resp", pathName)
+					continue
+				}
+
+				mediaType, ok := resp.Content["application/json"]
+				if !ok {
+					t.Errorf("%s: missing content type", pathName)
+					continue
+				}
+
+				if mediaType.Schema == nil {
+					t.Errorf("%s: missing media type schema", pathName)
+					continue
+				}
+
+				expectedRef := "#/components/schemas/" + pkgName + "." + rpc.output
+				if mediaType.Schema.Ref != expectedRef {
+					t.Errorf("%s: expected ref %q but got %q", pathName, expectedRef, mediaType.Schema.Ref)
+				}
+			}
+		}
+	})
+
+	t.Run("Messages", func(*testing.T) {
+		for _, message := range messages {
+			schemaName := "" + pkgName + "." + message.name
+			schema, ok := openAPI.Components.Schemas[schemaName]
+			if !ok {
+				t.Errorf("%s: missing message %q", schemaName, message.name)
+			}
+			if schema.Value == nil {
+				t.Errorf("%s: missing component", schemaName)
+				continue
+			}
+			properties := schema.Value.Properties
+			for _, messageField := range message.fields {
+				propertyRef, ok := properties[messageField.name]
+				if !ok {
+					t.Errorf("%s: missing property %q", schemaName, messageField.name)
+				}
+
+				if propertyRef == nil || propertyRef.Value == nil {
+					t.Errorf("%s: missing property ref", schemaName)
+					continue
+				}
+
+				property := propertyRef.Value
+				if property.Type != messageField.fieldType {
+					t.Errorf("%s: %q expected property type %q but got %q", schemaName, message.name, messageField.fieldType, property.Type)
+					continue
+				}
+
+				if messageField.format != "" {
+					if messageField.format != "" && property.Format != messageField.format {
+						t.Errorf("%s: expected property format %q but got %q", schemaName, messageField.format, property.Format)
+						continue
+					}
+				}
+
+				if propertyRef.Ref != messageField.ref {
+					t.Errorf("%s: %q expected reference %q but got %q", schemaName, messageField.name, messageField.ref, propertyRef.Ref)
+				}
+
+				// check the reference schema
+				if messageField.ref != "" {
+					refParts := strings.Split(messageField.ref, "/")
+					// the reference schema has the format of #/components/schemas/<type> so we need to get the last part
+					schemaRef, ok := openAPI.Components.Schemas[refParts[len(refParts)-1]]
+					if !ok {
+						t.Errorf("%s: %q expected reference schema %q but got nil", schemaName, messageField.name, messageField.ref)
+					} else {
+						// check if the schema reference has the expected enum values
+						if len(messageField.enums) > 0 {
+							if schemaRef.Value.Enum == nil {
+								t.Errorf("%s: %q expected reference schema enums %q but got nil", schemaName, messageField.name, messageField.ref)
+							} else {
+								enums := map[string]struct{}{}
+								for _, e := range schemaRef.Value.Enum {
+									enums[e.(string)] = struct{}{}
+								}
+								for _, e := range messageField.enums {
+									if _, ok := enums[e]; !ok {
+										t.Errorf("%s: %q expected reference schema enum %q to have %q but got nil", schemaName, messageField.name, messageField.ref, e)
+									}
+								}
+							}
+						}
+					}
+				}
+
+				if property.Type == "array" {
+					if property.Items == nil || property.Items.Value == nil {
+						t.Errorf("%s: missing property enum array items", schemaName)
+					}
+					// only check the array items type if it's not a reference
+					if messageField.itemsRef == "" && (property.Items.Value.Type != messageField.itemsType) {
+						t.Errorf("%s: expected %s items type %q but got %q", schemaName, messageField.name, messageField.itemsType, property.Items.Value.Type)
+					}
+					// check the array items reference schema
+					if property.Items.Ref != messageField.itemsRef {
+						t.Errorf("%s: expected %s items ref %q but got %q", schemaName, messageField.name, messageField.itemsRef, property.Items.Ref)
+					}
+				}
+			}
+		}
+	})
+}
diff --git a/cmd/twirp-openapi-gen/internal/generator/handlers.go b/cmd/twirp-openapi-gen/internal/generator/handlers.go
new file mode 100644
index 0000000..c11eb46
--- /dev/null
+++ b/cmd/twirp-openapi-gen/internal/generator/handlers.go
@@ -0,0 +1,562 @@
+package generator
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"log/slog"
+	"path/filepath"
+	"strings"
+	"unicode"
+
+	"github.com/emicklei/proto"
+	"github.com/getkin/kin-openapi/openapi3"
+)
+
+const (
+	googleAnyType       = "google.protobuf.Any"
+	googleListValueType = "google.protobuf.ListValue"
+	googleStructType    = "google.protobuf.Struct"
+	googleValueType     = "google.protobuf.Value"
+
+	googleMoneyType = "google.type.Money"
+)
+
+var (
+	successDescription = "Success"
+)
+
+func (gen *generator) Handlers() []proto.Handler {
+	return []proto.Handler{
+		proto.WithPackage(gen.Package),
+		proto.WithImport(gen.Import),
+		proto.WithRPC(gen.RPC),
+		proto.WithEnum(gen.Enum),
+		proto.WithMessage(gen.Message),
+	}
+}
+
+func (gen *generator) Package(pkg *proto.Package) {
+	slog.Debug("Package handler", "package", pkg.Name)
+	gen.packageName = pkg.Name
+}
+
+func (gen *generator) Import(i *proto.Import) {
+	slog.Debug("Import handler", "package", gen.packageName, "filename", i.Filename)
+
+	if _, ok := gen.importedFiles[i.Filename]; ok {
+		return
+	}
+	gen.importedFiles[i.Filename] = struct{}{}
+
+	// Instead of loading and generating the OpenAPI docs for the google proto definitions,
+	// its known types are mapped to OpenAPI types; see aliases.go.
+	if strings.Contains(i.Filename, "google/") {
+		return
+	}
+
+	protoFile, err := readProtoFile(i.Filename, gen.conf.protoPaths)
+	if err != nil {
+		slog.Error("could not import file", "filename", i.Filename, "error", err)
+		return
+	}
+
+	oldPackageName := gen.packageName
+
+	// Override the package name for the next round of Walk calls to preserve the types full import path
+	withPackage := func(pkg *proto.Package) {
+		gen.packageName = pkg.Name
+	}
+
+	// additional files walked for messages and imports only
+	proto.Walk(protoFile,
+		proto.WithPackage(withPackage),
+		proto.WithImport(gen.Import),
+		proto.WithRPC(gen.RPC),
+		proto.WithEnum(gen.Enum),
+		proto.WithMessage(gen.Message),
+	)
+
+	gen.packageName = oldPackageName
+}
+
+func (gen *generator) RPC(rpc *proto.RPC) {
+	slog.Debug("RPC handler", "package", gen.packageName, "rpc", rpc.Name, "requestType", rpc.RequestType, "returnsType", rpc.ReturnsType)
+
+	parent, ok := rpc.Parent.(*proto.Service)
+	if !ok {
+		log.Panicf("parent is not proto.service")
+	}
+	pathName := filepath.Join("/"+gen.conf.pathPrefix+"/", gen.packageName+"."+parent.Name, rpc.Name)
+
+	var reqMediaType *openapi3.MediaType
+	switch rpc.RequestType {
+	case "google.protobuf.Empty":
+		reqMediaType = openapi3.NewMediaType()