add swagger config

Makefile

@@ -1,12 +1,13 @@
 generate:
 	rm -rf proto
 	mkdir -p proto
-
+	protoc \
-	protoc -I ./api \
+	  -I ./api \
+	  -I ./third_party \
       --go_out ./proto --go_opt paths=source_relative \
       --go-grpc_out ./proto --go-grpc_opt paths=source_relative \
       --grpc-gateway_out ./proto --grpc-gateway_opt paths=source_relative \
-      --swagger_out=allow_merge=true,merge_file_name=main:./proto \
+      --swagger_out=allow_merge=true,merge_file_name=main:./resources \
       ./api/main.proto
 
 run:

api/main.proto

@@ -3,9 +3,12 @@ syntax = "proto3";
 package crabs.crm;
 
 import "google/api/annotations.proto";
+import "protoc-gen-openapiv2/options/annotations.proto";
 
 option go_package = "pkg/proto";
 
+option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_swagger) = {};
+
 service CRM {
   rpc GetCatalog(GetCatalogReq) returns (CatalogRsp) {
     option (google.api.http) = {

cmd/cake_crm/main.go

@@ -11,14 +11,11 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"os"
 )
 
 func main() {
-	//ctx, cancel := context.WithCancel(context.Background())
-	//defer cancel()
-
 	storage := storage_file.NewStorageFile()
-	_ = storage
 
 	// Create a listener on TCP port
 	lis, err := net.Listen("tcp", ":8080")
@@ -46,16 +43,28 @@ func main() {
 		log.Fatalln("Failed to dial server:", err)
 	}
 
-	gwmux := runtime.NewServeMux()
+	mux := runtime.NewServeMux()
 	// Register Greeter
-	err = proto.RegisterCRMHandler(context.Background(), gwmux, conn)
+	err = proto.RegisterCRMHandler(context.Background(), mux, conn)
 	if err != nil {
 		log.Fatalln("Failed to register gateway:", err)
 	}
 
+	err = mux.HandlePath("GET", "/swagger", func(w http.ResponseWriter, r *http.Request, pathParams map[string]string) {
+		data, err := os.ReadFile("resources/main.swagger.json")
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+		}
+		_, _ = w.Write(data)
+	})
+	if err != nil {
+		panic(err)
+	}
+	log.Println("Serving swagger json on http://0.0.0.0:8090/swagger")
+
 	gwServer := &http.Server{
 		Addr:    ":8090",
-		Handler: gwmux,
+		Handler: mux,
 	}
 
 	log.Println("Serving gRPC-Gateway on http://0.0.0.0:8090")

proto/main.pb.go

@@ -4,9 +4,10 @@
 // 	protoc        v5.26.1
 // source: main.proto
 
-package crm
+package proto
 
 import (
+	_ "github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2/options"
 	_ "google.golang.org/genproto/googleapis/api/annotations"
 	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
 	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
@@ -828,6 +829,9 @@ var file_main_proto_rawDesc = []byte{
 	0x0a, 0x0a, 0x6d, 0x61, 0x69, 0x6e, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x12, 0x09, 0x63, 0x72,
 	0x61, 0x62, 0x73, 0x2e, 0x63, 0x72, 0x6d, 0x1a, 0x1c, 0x67, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x2f,
 	0x61, 0x70, 0x69, 0x2f, 0x61, 0x6e, 0x6e, 0x6f, 0x74, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x2e,
+	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x1a, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x63, 0x2d, 0x67, 0x65,
+	0x6e, 0x2d, 0x6f, 0x70, 0x65, 0x6e, 0x61, 0x70, 0x69, 0x76, 0x32, 0x2f, 0x6f, 0x70, 0x74, 0x69,
+	0x6f, 0x6e, 0x73, 0x2f, 0x61, 0x6e, 0x6e, 0x6f, 0x74, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x2e,
 	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22, 0x0f, 0x0a, 0x0d, 0x47, 0x65, 0x74, 0x43, 0x61, 0x74, 0x61,
 	0x6c, 0x6f, 0x67, 0x52, 0x65, 0x71, 0x22, 0x41, 0x0a, 0x0a, 0x43, 0x61, 0x74, 0x61, 0x6c, 0x6f,
 	0x67, 0x52, 0x73, 0x70, 0x12, 0x33, 0x0a, 0x0a, 0x63, 0x61, 0x74, 0x65, 0x67, 0x6f, 0x72, 0x69,
@@ -926,8 +930,8 @@ var file_main_proto_rawDesc = []byte{
 	0x61, 0x62, 0x73, 0x2e, 0x63, 0x72, 0x6d, 0x2e, 0x42, 0x72, 0x65, 0x61, 0x64, 0x63, 0x72, 0x75,
 	0x6d, 0x62, 0x73, 0x52, 0x73, 0x70, 0x22, 0x19, 0x82, 0xd3, 0xe4, 0x93, 0x02, 0x13, 0x12, 0x11,
 	0x2f, 0x62, 0x72, 0x65, 0x61, 0x64, 0x63, 0x72, 0x75, 0x6d, 0x62, 0x73, 0x2f, 0x7b, 0x69, 0x64,
-	0x7d, 0x42, 0x09, 0x5a, 0x07, 0x70, 0x6b, 0x67, 0x2f, 0x63, 0x72, 0x6d, 0x62, 0x06, 0x70, 0x72,
+	0x7d, 0x42, 0x0e, 0x92, 0x41, 0x00, 0x5a, 0x09, 0x70, 0x6b, 0x67, 0x2f, 0x70, 0x72, 0x6f, 0x74,
-	0x6f, 0x74, 0x6f, 0x33,
+	0x6f, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
 }
 
 var (

proto/main.pb.gw.go

@@ -2,11 +2,11 @@
 // source: main.proto
 
 /*
-Package crm is a reverse proxy.
+Package proto is a reverse proxy.
 
 It translates gRPC into RESTful JSON APIs.
 */
-package crm
+package proto
 
 import (
 	"context"

proto/main_grpc.pb.go

@@ -4,7 +4,7 @@
 // - protoc             v5.26.1
 // source: main.proto
 
-package crm
+package proto
 
 import (
 	context "context"

third_party/protoc-gen-openapiv2/options/annotations.proto

@@ -0,0 +1,44 @@
+syntax = "proto3";
+
+package grpc.gateway.protoc_gen_openapiv2.options;
+
+import "google/protobuf/descriptor.proto";
+import "protoc-gen-openapiv2/options/openapiv2.proto";
+
+option go_package = "github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2/options";
+
+extend google.protobuf.FileOptions {
+  // ID assigned by protobuf-global-extension-registry@google.com for gRPC-Gateway project.
+  //
+  // All IDs are the same, as assigned. It is okay that they are the same, as they extend
+  // different descriptor messages.
+  Swagger openapiv2_swagger = 1042;
+}
+extend google.protobuf.MethodOptions {
+  // ID assigned by protobuf-global-extension-registry@google.com for gRPC-Gateway project.
+  //
+  // All IDs are the same, as assigned. It is okay that they are the same, as they extend
+  // different descriptor messages.
+  Operation openapiv2_operation = 1042;
+}
+extend google.protobuf.MessageOptions {
+  // ID assigned by protobuf-global-extension-registry@google.com for gRPC-Gateway project.
+  //
+  // All IDs are the same, as assigned. It is okay that they are the same, as they extend
+  // different descriptor messages.
+  Schema openapiv2_schema = 1042;
+}
+extend google.protobuf.ServiceOptions {
+  // ID assigned by protobuf-global-extension-registry@google.com for gRPC-Gateway project.
+  //
+  // All IDs are the same, as assigned. It is okay that they are the same, as they extend
+  // different descriptor messages.
+  Tag openapiv2_tag = 1042;
+}
+extend google.protobuf.FieldOptions {
+  // ID assigned by protobuf-global-extension-registry@google.com for gRPC-Gateway project.
+  //
+  // All IDs are the same, as assigned. It is okay that they are the same, as they extend
+  // different descriptor messages.
+  JSONSchema openapiv2_field = 1042;
+}

third_party/protoc-gen-openapiv2/options/openapiv2.proto

@@ -0,0 +1,720 @@
+syntax = "proto3";
+
+package grpc.gateway.protoc_gen_openapiv2.options;
+
+import "google/protobuf/struct.proto";
+
+option go_package = "github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2/options";
+
+// Scheme describes the schemes supported by the OpenAPI Swagger
+// and Operation objects.
+enum Scheme {
+  UNKNOWN = 0;
+  HTTP = 1;
+  HTTPS = 2;
+  WS = 3;
+  WSS = 4;
+}
+
+// `Swagger` is a representation of OpenAPI v2 specification's Swagger object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#swaggerObject
+//
+// Example:
+//
+//  option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_swagger) = {
+//    info: {
+//      title: "Echo API";
+//      version: "1.0";
+//      description: "";
+//      contact: {
+//        name: "gRPC-Gateway project";
+//        url: "https://github.com/grpc-ecosystem/grpc-gateway";
+//        email: "none@example.com";
+//      };
+//      license: {
+//        name: "BSD 3-Clause License";
+//        url: "https://github.com/grpc-ecosystem/grpc-gateway/blob/main/LICENSE";
+//      };
+//    };
+//    schemes: HTTPS;
+//    consumes: "application/json";
+//    produces: "application/json";
+//  };
+//
+message Swagger {
+  // Specifies the OpenAPI Specification version being used. It can be
+  // used by the OpenAPI UI and other clients to interpret the API listing. The
+  // value MUST be "2.0".
+  string swagger = 1;
+  // Provides metadata about the API. The metadata can be used by the
+  // clients if needed.
+  Info info = 2;
+  // The host (name or ip) serving the API. This MUST be the host only and does
+  // not include the scheme nor sub-paths. It MAY include a port. If the host is
+  // not included, the host serving the documentation is to be used (including
+  // the port). The host does not support path templating.
+  string host = 3;
+  // The base path on which the API is served, which is relative to the host. If
+  // it is not included, the API is served directly under the host. The value
+  // MUST start with a leading slash (/). The basePath does not support path
+  // templating.
+  // Note that using `base_path` does not change the endpoint paths that are
+  // generated in the resulting OpenAPI file. If you wish to use `base_path`
+  // with relatively generated OpenAPI paths, the `base_path` prefix must be
+  // manually removed from your `google.api.http` paths and your code changed to
+  // serve the API from the `base_path`.
+  string base_path = 4;
+  // The transfer protocol of the API. Values MUST be from the list: "http",
+  // "https", "ws", "wss". If the schemes is not included, the default scheme to
+  // be used is the one used to access the OpenAPI definition itself.
+  repeated Scheme schemes = 5;
+  // A list of MIME types the APIs can consume. This is global to all APIs but
+  // can be overridden on specific API calls. Value MUST be as described under
+  // Mime Types.
+  repeated string consumes = 6;
+  // A list of MIME types the APIs can produce. This is global to all APIs but
+  // can be overridden on specific API calls. Value MUST be as described under
+  // Mime Types.
+  repeated string produces = 7;
+  // field 8 is reserved for 'paths'.
+  reserved 8;
+  // field 9 is reserved for 'definitions', which at this time are already
+  // exposed as and customizable as proto messages.
+  reserved 9;
+  // An object to hold responses that can be used across operations. This
+  // property does not define global responses for all operations.
+  map<string, Response> responses = 10;
+  // Security scheme definitions that can be used across the specification.
+  SecurityDefinitions security_definitions = 11;
+  // A declaration of which security schemes are applied for the API as a whole.
+  // The list of values describes alternative security schemes that can be used
+  // (that is, there is a logical OR between the security requirements).
+  // Individual operations can override this definition.
+  repeated SecurityRequirement security = 12;
+  // A list of tags for API documentation control. Tags can be used for logical
+  // grouping of operations by resources or any other qualifier.
+  repeated Tag tags = 13;
+  // Additional external documentation.
+  ExternalDocumentation external_docs = 14;
+  // Custom properties that start with "x-" such as "x-foo" used to describe
+  // extra functionality that is not covered by the standard OpenAPI Specification.
+  // See: https://swagger.io/docs/specification/2-0/swagger-extensions/
+  map<string, google.protobuf.Value> extensions = 15;
+}
+
+// `Operation` is a representation of OpenAPI v2 specification's Operation object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#operationObject
+//
+// Example:
+//
+//  service EchoService {
+//    rpc Echo(SimpleMessage) returns (SimpleMessage) {
+//      option (google.api.http) = {
+//        get: "/v1/example/echo/{id}"
+//      };
+//
+//      option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_operation) = {
+//        summary: "Get a message.";
+//        operation_id: "getMessage";
+//        tags: "echo";
+//        responses: {
+//          key: "200"
+//            value: {
+//            description: "OK";
+//          }
+//        }
+//      };
+//    }
+//  }
+message Operation {
+  // A list of tags for API documentation control. Tags can be used for logical
+  // grouping of operations by resources or any other qualifier.
+  repeated string tags = 1;
+  // A short summary of what the operation does. For maximum readability in the
+  // swagger-ui, this field SHOULD be less than 120 characters.
+  string summary = 2;
+  // A verbose explanation of the operation behavior. GFM syntax can be used for
+  // rich text representation.
+  string description = 3;
+  // Additional external documentation for this operation.
+  ExternalDocumentation external_docs = 4;
+  // Unique string used to identify the operation. The id MUST be unique among
+  // all operations described in the API. Tools and libraries MAY use the
+  // operationId to uniquely identify an operation, therefore, it is recommended
+  // to follow common programming naming conventions.
+  string operation_id = 5;
+  // A list of MIME types the operation can consume. This overrides the consumes
+  // definition at the OpenAPI Object. An empty value MAY be used to clear the
+  // global definition. Value MUST be as described under Mime Types.
+  repeated string consumes = 6;
+  // A list of MIME types the operation can produce. This overrides the produces
+  // definition at the OpenAPI Object. An empty value MAY be used to clear the
+  // global definition. Value MUST be as described under Mime Types.
+  repeated string produces = 7;
+  // field 8 is reserved for 'parameters'.
+  reserved 8;
+  // The list of possible responses as they are returned from executing this
+  // operation.
+  map<string, Response> responses = 9;
+  // The transfer protocol for the operation. Values MUST be from the list:
+  // "http", "https", "ws", "wss". The value overrides the OpenAPI Object
+  // schemes definition.
+  repeated Scheme schemes = 10;
+  // Declares this operation to be deprecated. Usage of the declared operation
+  // should be refrained. Default value is false.
+  bool deprecated = 11;
+  // A declaration of which security schemes are applied for this operation. The
+  // list of values describes alternative security schemes that can be used
+  // (that is, there is a logical OR between the security requirements). This
+  // definition overrides any declared top-level security. To remove a top-level
+  // security declaration, an empty array can be used.
+  repeated SecurityRequirement security = 12;
+  // Custom properties that start with "x-" such as "x-foo" used to describe
+  // extra functionality that is not covered by the standard OpenAPI Specification.
+  // See: https://swagger.io/docs/specification/2-0/swagger-extensions/
+  map<string, google.protobuf.Value> extensions = 13;
+  // Custom parameters such as HTTP request headers.
+  // See: https://swagger.io/docs/specification/2-0/describing-parameters/
+  // and https://swagger.io/specification/v2/#parameter-object.
+  Parameters parameters = 14;
+}
+
+// `Parameters` is a representation of OpenAPI v2 specification's parameters object.
+// Note: This technically breaks compatibility with the OpenAPI 2 definition structure as we only
+// allow header parameters to be set here since we do not want users specifying custom non-header
+// parameters beyond those inferred from the Protobuf schema.
+// See: https://swagger.io/specification/v2/#parameter-object
+message Parameters {
+  // `Headers` is one or more HTTP header parameter.
+  // See: https://swagger.io/docs/specification/2-0/describing-parameters/#header-parameters
+  repeated HeaderParameter headers = 1;
+}
+
+// `HeaderParameter` a HTTP header parameter.
+// See: https://swagger.io/specification/v2/#parameter-object
+message HeaderParameter {
+  // `Type` is a supported HTTP header type.
+  // See https://swagger.io/specification/v2/#parameterType.
+  enum Type {
+    UNKNOWN = 0;
+    STRING = 1;
+    NUMBER = 2;
+    INTEGER = 3;
+    BOOLEAN = 4;
+  }
+
+  // `Name` is the header name.
+  string name = 1;
+  // `Description` is a short description of the header.
+  string description = 2;
+  // `Type` is the type of the object. The value MUST be one of "string", "number", "integer", or "boolean". The "array" type is not supported.
+  // See: https://swagger.io/specification/v2/#parameterType.
+  Type type = 3;
+  // `Format` The extending format for the previously mentioned type.
+  string format = 4;
+  // `Required` indicates if the header is optional
+  bool required = 5;
+  // field 6 is reserved for 'items', but in OpenAPI-specific way.
+  reserved 6;
+  // field 7 is reserved `Collection Format`. Determines the format of the array if type array is used.
+  reserved 7;
+}
+
+// `Header` is a representation of OpenAPI v2 specification's Header object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#headerObject
+//
+message Header {
+  // `Description` is a short description of the header.
+  string description = 1;
+  // The type of the object. The value MUST be one of "string", "number", "integer", or "boolean". The "array" type is not supported.
+  string type = 2;
+  // `Format` The extending format for the previously mentioned type.
+  string format = 3;
+  // field 4 is reserved for 'items', but in OpenAPI-specific way.
+  reserved 4;
+  // field 5 is reserved `Collection Format` Determines the format of the array if type array is used.
+  reserved 5;
+  // `Default` Declares the value of the header that the server will use if none is provided.
+  // See: https://tools.ietf.org/html/draft-fge-json-schema-validation-00#section-6.2.
+  // Unlike JSON Schema this value MUST conform to the defined type for the header.
+  string default = 6;
+  // field 7 is reserved for 'maximum'.
+  reserved 7;
+  // field 8 is reserved for 'exclusiveMaximum'.
+  reserved 8;
+  // field 9 is reserved for 'minimum'.
+  reserved 9;
+  // field 10 is reserved for 'exclusiveMinimum'.
+  reserved 10;
+  // field 11 is reserved for 'maxLength'.
+  reserved 11;
+  // field 12 is reserved for 'minLength'.
+  reserved 12;
+  // 'Pattern' See https://tools.ietf.org/html/draft-fge-json-schema-validation-00#section-5.2.3.
+  string pattern = 13;
+  // field 14 is reserved for 'maxItems'.
+  reserved 14;
+  // field 15 is reserved for 'minItems'.
+  reserved 15;
+  // field 16 is reserved for 'uniqueItems'.
+  reserved 16;
+  // field 17 is reserved for 'enum'.
+  reserved 17;
+  // field 18 is reserved for 'multipleOf'.
+  reserved 18;
+}
+
+// `Response` is a representation of OpenAPI v2 specification's Response object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#responseObject
+//
+message Response {
+  // `Description` is a short description of the response.
+  // GFM syntax can be used for rich text representation.
+  string description = 1;
+  // `Schema` optionally defines the structure of the response.
+  // If `Schema` is not provided, it means there is no content to the response.
+  Schema schema = 2;
+  // `Headers` A list of headers that are sent with the response.
+  // `Header` name is expected to be a string in the canonical format of the MIME header key
+  // See: https://golang.org/pkg/net/textproto/#CanonicalMIMEHeaderKey
+  map<string, Header> headers = 3;
+  // `Examples` gives per-mimetype response examples.
+  // See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#example-object
+  map<string, string> examples = 4;
+  // Custom properties that start with "x-" such as "x-foo" used to describe
+  // extra functionality that is not covered by the standard OpenAPI Specification.
+  // See: https://swagger.io/docs/specification/2-0/swagger-extensions/
+  map<string, google.protobuf.Value> extensions = 5;
+}
+
+// `Info` is a representation of OpenAPI v2 specification's Info object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#infoObject
+//
+// Example:
+//
+//  option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_swagger) = {
+//    info: {
+//      title: "Echo API";
+//      version: "1.0";
+//      description: "";
+//      contact: {
+//        name: "gRPC-Gateway project";
+//        url: "https://github.com/grpc-ecosystem/grpc-gateway";
+//        email: "none@example.com";
+//      };
+//      license: {
+//        name: "BSD 3-Clause License";
+//        url: "https://github.com/grpc-ecosystem/grpc-gateway/blob/main/LICENSE";
+//      };
+//    };
+//    ...
+//  };
+//
+message Info {
+  // The title of the application.
+  string title = 1;
+  // A short description of the application. GFM syntax can be used for rich
+  // text representation.
+  string description = 2;
+  // The Terms of Service for the API.
+  string terms_of_service = 3;
+  // The contact information for the exposed API.
+  Contact contact = 4;
+  // The license information for the exposed API.
+  License license = 5;
+  // Provides the version of the application API (not to be confused
+  // with the specification version).
+  string version = 6;
+  // Custom properties that start with "x-" such as "x-foo" used to describe
+  // extra functionality that is not covered by the standard OpenAPI Specification.
+  // See: https://swagger.io/docs/specification/2-0/swagger-extensions/
+  map<string, google.protobuf.Value> extensions = 7;
+}
+
+// `Contact` is a representation of OpenAPI v2 specification's Contact object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#contactObject
+//
+// Example:
+//
+//  option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_swagger) = {
+//    info: {
+//      ...
+//      contact: {
+//        name: "gRPC-Gateway project";
+//        url: "https://github.com/grpc-ecosystem/grpc-gateway";
+//        email: "none@example.com";
+//      };
+//      ...
+//    };
+//    ...
+//  };
+//
+message Contact {
+  // The identifying name of the contact person/organization.
+  string name = 1;
+  // The URL pointing to the contact information. MUST be in the format of a
+  // URL.
+  string url = 2;
+  // The email address of the contact person/organization. MUST be in the format
+  // of an email address.
+  string email = 3;
+}
+
+// `License` is a representation of OpenAPI v2 specification's License object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#licenseObject
+//
+// Example:
+//
+//  option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_swagger) = {
+//    info: {
+//      ...
+//      license: {
+//        name: "BSD 3-Clause License";
+//        url: "https://github.com/grpc-ecosystem/grpc-gateway/blob/main/LICENSE";
+//      };
+//      ...
+//    };
+//    ...
+//  };
+//
+message License {
+  // The license name used for the API.
+  string name = 1;
+  // A URL to the license used for the API. MUST be in the format of a URL.
+  string url = 2;
+}
+
+// `ExternalDocumentation` is a representation of OpenAPI v2 specification's
+// ExternalDocumentation object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#externalDocumentationObject
+//
+// Example:
+//
+//  option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_swagger) = {
+//    ...
+//    external_docs: {
+//      description: "More about gRPC-Gateway";
+//      url: "https://github.com/grpc-ecosystem/grpc-gateway";
+//    }
+//    ...
+//  };
+//
+message ExternalDocumentation {
+  // A short description of the target documentation. GFM syntax can be used for
+  // rich text representation.
+  string description = 1;
+  // The URL for the target documentation. Value MUST be in the format
+  // of a URL.
+  string url = 2;
+}
+
+// `Schema` is a representation of OpenAPI v2 specification's Schema object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#schemaObject
+//
+message Schema {
+  JSONSchema json_schema = 1;
+  // Adds support for polymorphism. The discriminator is the schema property
+  // name that is used to differentiate between other schema that inherit this
+  // schema. The property name used MUST be defined at this schema and it MUST
+  // be in the required property list. When used, the value MUST be the name of
+  // this schema or any schema that inherits it.
+  string discriminator = 2;
+  // Relevant only for Schema "properties" definitions. Declares the property as
+  // "read only". This means that it MAY be sent as part of a response but MUST
+  // NOT be sent as part of the request. Properties marked as readOnly being
+  // true SHOULD NOT be in the required list of the defined schema. Default
+  // value is false.
+  bool read_only = 3;
+  // field 4 is reserved for 'xml'.
+  reserved 4;
+  // Additional external documentation for this schema.
+  ExternalDocumentation external_docs = 5;
+  // A free-form property to include an example of an instance for this schema in JSON.
+  // This is copied verbatim to the output.
+  string example = 6;
+}
+
+// `JSONSchema` represents properties from JSON Schema taken, and as used, in
+// the OpenAPI v2 spec.
+//
+// This includes changes made by OpenAPI v2.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#schemaObject
+//
+// See also: https://cswr.github.io/JsonSchema/spec/basic_types/,
+// https://github.com/json-schema-org/json-schema-spec/blob/master/schema.json
+//
+// Example:
+//
+//  message SimpleMessage {
+//    option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_schema) = {
+//      json_schema: {
+//        title: "SimpleMessage"
+//        description: "A simple message."
+//        required: ["id"]
+//      }
+//    };
+//
+//    // Id represents the message identifier.
+//    string id = 1; [
+//        (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_field) = {
+//          description: "The unique identifier of the simple message."
+//        }];
+//  }
+//
+message JSONSchema {
+  // field 1 is reserved for '$id', omitted from OpenAPI v2.
+  reserved 1;
+  // field 2 is reserved for '$schema', omitted from OpenAPI v2.
+  reserved 2;
+  // Ref is used to define an external reference to include in the message.
+  // This could be a fully qualified proto message reference, and that type must
+  // be imported into the protofile. If no message is identified, the Ref will
+  // be used verbatim in the output.
+  // For example:
+  //  `ref: ".google.protobuf.Timestamp"`.
+  string ref = 3;
+  // field 4 is reserved for '$comment', omitted from OpenAPI v2.
+  reserved 4;
+  // The title of the schema.
+  string title = 5;
+  // A short description of the schema.
+  string description = 6;
+  string default = 7;
+  bool read_only = 8;
+  // A free-form property to include a JSON example of this field. This is copied
+  // verbatim to the output swagger.json. Quotes must be escaped.
+  // This property is the same for 2.0 and 3.0.0 https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/3.0.0.md#schemaObject  https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#schemaObject
+  string example = 9;
+  double multiple_of = 10;
+  // Maximum represents an inclusive upper limit for a numeric instance. The
+  // value of MUST be a number,
+  double maximum = 11;
+  bool exclusive_maximum = 12;
+  // minimum represents an inclusive lower limit for a numeric instance. The
+  // value of MUST be a number,
+  double minimum = 13;
+  bool exclusive_minimum = 14;
+  uint64 max_length = 15;
+  uint64 min_length = 16;
+  string pattern = 17;
+  // field 18 is reserved for 'additionalItems', omitted from OpenAPI v2.
+  reserved 18;
+  // field 19 is reserved for 'items', but in OpenAPI-specific way.
+  // TODO(ivucica): add 'items'?
+  reserved 19;
+  uint64 max_items = 20;
+  uint64 min_items = 21;
+  bool unique_items = 22;
+  // field 23 is reserved for 'contains', omitted from OpenAPI v2.
+  reserved 23;
+  uint64 max_properties = 24;
+  uint64 min_properties = 25;
+  repeated string required = 26;
+  // field 27 is reserved for 'additionalProperties', but in OpenAPI-specific
+  // way. TODO(ivucica): add 'additionalProperties'?
+  reserved 27;
+  // field 28 is reserved for 'definitions', omitted from OpenAPI v2.
+  reserved 28;
+  // field 29 is reserved for 'properties', but in OpenAPI-specific way.
+  // TODO(ivucica): add 'additionalProperties'?
+  reserved 29;
+  // following fields are reserved, as the properties have been omitted from
+  // OpenAPI v2:
+  // patternProperties, dependencies, propertyNames, const
+  reserved 30 to 33;
+  // Items in 'array' must be unique.
+  repeated string array = 34;
+
+  enum JSONSchemaSimpleTypes {
+    UNKNOWN = 0;
+    ARRAY = 1;
+    BOOLEAN = 2;
+    INTEGER = 3;
+    NULL = 4;
+    NUMBER = 5;
+    OBJECT = 6;
+    STRING = 7;
+  }
+
+  repeated JSONSchemaSimpleTypes type = 35;
+  // `Format`
+  string format = 36;
+  // following fields are reserved, as the properties have been omitted from
+  // OpenAPI v2: contentMediaType, contentEncoding, if, then, else
+  reserved 37 to 41;
+  // field 42 is reserved for 'allOf', but in OpenAPI-specific way.
+  // TODO(ivucica): add 'allOf'?
+  reserved 42;
+  // following fields are reserved, as the properties have been omitted from
+  // OpenAPI v2:
+  // anyOf, oneOf, not
+  reserved 43 to 45;
+  // Items in `enum` must be unique https://tools.ietf.org/html/draft-fge-json-schema-validation-00#section-5.5.1
+  repeated string enum = 46;
+
+  // Additional field level properties used when generating the OpenAPI v2 file.
+  FieldConfiguration field_configuration = 1001;
+
+  // 'FieldConfiguration' provides additional field level properties used when generating the OpenAPI v2 file.
+  // These properties are not defined by OpenAPIv2, but they are used to control the generation.
+  message FieldConfiguration {
+    // Alternative parameter name when used as path parameter. If set, this will
+    // be used as the complete parameter name when this field is used as a path
+    // parameter. Use this to avoid having auto generated path parameter names
+    // for overlapping paths.
+    string path_param_name = 47;
+  }
+  // Custom properties that start with "x-" such as "x-foo" used to describe
+  // extra functionality that is not covered by the standard OpenAPI Specification.
+  // See: https://swagger.io/docs/specification/2-0/swagger-extensions/
+  map<string, google.protobuf.Value> extensions = 48;
+}
+
+// `Tag` is a representation of OpenAPI v2 specification's Tag object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#tagObject
+//
+message Tag {
+  // The name of the tag. Use it to allow override of the name of a
+  // global Tag object, then use that name to reference the tag throughout the
+  // OpenAPI file.
+  string name = 1;
+  // A short description for the tag. GFM syntax can be used for rich text
+  // representation.
+  string description = 2;
+  // Additional external documentation for this tag.
+  ExternalDocumentation external_docs = 3;
+  // Custom properties that start with "x-" such as "x-foo" used to describe
+  // extra functionality that is not covered by the standard OpenAPI Specification.
+  // See: https://swagger.io/docs/specification/2-0/swagger-extensions/
+  map<string, google.protobuf.Value> extensions = 4;
+}
+
+// `SecurityDefinitions` is a representation of OpenAPI v2 specification's
+// Security Definitions object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#securityDefinitionsObject
+//
+// A declaration of the security schemes available to be used in the
+// specification. This does not enforce the security schemes on the operations
+// and only serves to provide the relevant details for each scheme.
+message SecurityDefinitions {
+  // A single security scheme definition, mapping a "name" to the scheme it
+  // defines.
+  map<string, SecurityScheme> security = 1;
+}
+
+// `SecurityScheme` is a representation of OpenAPI v2 specification's
+// Security Scheme object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#securitySchemeObject
+//
+// Allows the definition of a security scheme that can be used by the
+// operations. Supported schemes are basic authentication, an API key (either as
+// a header or as a query parameter) and OAuth2's common flows (implicit,
+// password, application and access code).
+message SecurityScheme {
+  // The type of the security scheme. Valid values are "basic",
+  // "apiKey" or "oauth2".
+  enum Type {
+    TYPE_INVALID = 0;
+    TYPE_BASIC = 1;
+    TYPE_API_KEY = 2;
+    TYPE_OAUTH2 = 3;
+  }
+
+  // The location of the API key. Valid values are "query" or "header".
+  enum In {
+    IN_INVALID = 0;
+    IN_QUERY = 1;
+    IN_HEADER = 2;
+  }
+
+  // The flow used by the OAuth2 security scheme. Valid values are
+  // "implicit", "password", "application" or "accessCode".
+  enum Flow {
+    FLOW_INVALID = 0;
+    FLOW_IMPLICIT = 1;
+    FLOW_PASSWORD = 2;
+    FLOW_APPLICATION = 3;
+    FLOW_ACCESS_CODE = 4;
+  }
+
+  // The type of the security scheme. Valid values are "basic",
+  // "apiKey" or "oauth2".
+  Type type = 1;
+  // A short description for security scheme.
+  string description = 2;
+  // The name of the header or query parameter to be used.
+  // Valid for apiKey.
+  string name = 3;
+  // The location of the API key. Valid values are "query" or
+  // "header".
+  // Valid for apiKey.
+  In in = 4;
+  // The flow used by the OAuth2 security scheme. Valid values are
+  // "implicit", "password", "application" or "accessCode".
+  // Valid for oauth2.
+  Flow flow = 5;
+  // The authorization URL to be used for this flow. This SHOULD be in
+  // the form of a URL.
+  // Valid for oauth2/implicit and oauth2/accessCode.
+  string authorization_url = 6;
+  // The token URL to be used for this flow. This SHOULD be in the
+  // form of a URL.
+  // Valid for oauth2/password, oauth2/application and oauth2/accessCode.
+  string token_url = 7;
+  // The available scopes for the OAuth2 security scheme.
+  // Valid for oauth2.
+  Scopes scopes = 8;
+  // Custom properties that start with "x-" such as "x-foo" used to describe
+  // extra functionality that is not covered by the standard OpenAPI Specification.
+  // See: https://swagger.io/docs/specification/2-0/swagger-extensions/
+  map<string, google.protobuf.Value> extensions = 9;
+}
+
+// `SecurityRequirement` is a representation of OpenAPI v2 specification's
+// Security Requirement object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#securityRequirementObject
+//
+// Lists the required security schemes to execute this operation. The object can
+// have multiple security schemes declared in it which are all required (that
+// is, there is a logical AND between the schemes).
+//
+// The name used for each property MUST correspond to a security scheme
+// declared in the Security Definitions.
+message SecurityRequirement {
+  // If the security scheme is of type "oauth2", then the value is a list of
+  // scope names required for the execution. For other security scheme types,
+  // the array MUST be empty.
+  message SecurityRequirementValue {
+    repeated string scope = 1;
+  }
+  // Each name must correspond to a security scheme which is declared in
+  // the Security Definitions. If the security scheme is of type "oauth2",
+  // then the value is a list of scope names required for the execution.
+  // For other security scheme types, the array MUST be empty.
+  map<string, SecurityRequirementValue> security_requirement = 1;
+}
+
+// `Scopes` is a representation of OpenAPI v2 specification's Scopes object.
+//
+// See: https://github.com/OAI/OpenAPI-Specification/blob/3.0.0/versions/2.0.md#scopesObject
+//
+// Lists the available scopes for an OAuth2 security scheme.
+message Scopes {
+  // Maps between a name of a scope to a short description of it (as the value
+  // of the property).
+  map<string, string> scope = 1;
+}