Protocol Buffers, GraphQL Schema, Swagger Specで始めるスキーマファースト開発入門

syntax = "proto3";
package com.kinto_technologies.blog;
option go_package = "blog.kinto-technologies.com";
import "google/api/annotations.proto"; // 準備1で取得したファイルの読み込み
import "protobuf/graphql.proto"; // 準備2で取得したファイルの読み込み

// 記事
message Article {
  // タイトル
  string title = 1;
  // 著者
  string author = 2;
  // コンテンツ
  string content = 3;
}

// リクエスト
message Request {
  uint64 id = 1;
}

// 結果
message Result {
  uint64 id = 1;
}

// テックブログサービス
service TechBlog {
  // 記事投稿
  rpc PostArticle(Article) returns (Result) {
    option (google.api.http) = {
      post: "/post"
    };
    option (danielvladco.protobuf.graphql.rpc) = {
      type: MUTATION
    };
  }

  // 記事取得
  rpc GetArticle(Request) returns (Article) {
    option (google.api.http) = {
      get: "/get/{id}"
    };
    option (danielvladco.protobuf.graphql.rpc) = {
      type: QUERY
    };
  }
}

git clone https://github.com/danielvladco/go-proto-gql.git

cd go-proto-gql

cd ./protoc-gen-gql
go install

protoc --gql_out=paths=source_relative:. -I=. example.proto

"""
 テックブログサービス

"""
directive @TechBlog on FIELD_DEFINITION
"""
 記事

"""
type Article {
	"""
	 タイトル

	"""
	title: String
	"""
	 著者

	"""
	author: String
	"""
	 コンテンツ

	"""
	content: String
}
"""
 記事

"""
input ArticleInput {
	"""
	 タイトル

	"""
	title: String
	"""
	 著者

	"""
	author: String
	"""
	 コンテンツ

	"""
	content: String
}
type Mutation {
	"""
	 記事投稿

	"""
	techBlogPostArticle(in: ArticleInput): Result
}
type Query {
	"""
	 記事取得

	"""
	techBlogGetArticle(in: RequestInput): Article
}
"""
 リクエスト

"""
input RequestInput {
	id: Int
}
"""
 結果

"""
type Result {
	id: Int
}

brew install protobuf

go install github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2@latest

protoc -I . --openapiv2_out=allow_merge=true,merge_file_name=./example:. example.proto

{
  "swagger": "2.0",
  "info": {
    "title": "example.proto",
    "version": "version not set"
  },
  "tags": [
    {
      "name": "TechBlog"
    }
  ],
  "consumes": [
    "application/json"
  ],
  "produces": [
    "application/json"
  ],
  "paths": {
    "/get/{id}": {
      "get": {
        "summary": "記事取得",
        "operationId": "TechBlog_GetArticle",
        "responses": {
          "200": {
            "description": "A successful response.",
            "schema": {
              "$ref": "#/definitions/blogArticle"
            }
          },
          "default": {
            "description": "An unexpected error response.",
            "schema": {
              "$ref": "#/definitions/rpcStatus"
            }
          }
        },
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "type": "string",
            "format": "uint64"
          }
        ],
        "tags": [
          "TechBlog"
        ]
      }
    },
    "/post": {
      "post": {
        "summary": "記事投稿",
        "operationId": "TechBlog_PostArticle",
        "responses": {
          "200": {
            "description": "A successful response.",
            "schema": {
              "$ref": "#/definitions/blogResult"
            }
          },
          "default": {
            "description": "An unexpected error response.",
            "schema": {
              "$ref": "#/definitions/rpcStatus"
            }
          }
        },
        "parameters": [
          {
            "name": "title",
            "description": "タイトル",
            "in": "query",
            "required": false,
            "type": "string"
          },
          {
            "name": "author",
            "description": "著者",
            "in": "query",
            "required": false,
            "type": "string"
          },
          {
            "name": "content",
            "description": "コンテンツ",
            "in": "query",
            "required": false,
            "type": "string"
          }
        ],
        "tags": [
          "TechBlog"
        ]
      }
    }
  },
  "definitions": {
    "blogArticle": {
      "type": "object",
      "properties": {
        "title": {
          "type": "string",
          "title": "タイトル"
        },
        "author": {
          "type": "string",
          "title": "著者"
        },
        "content": {
          "type": "string",
          "title": "コンテンツ"
        }
      },
      "title": "記事"
    },
    "blogResult": {
      "type": "object",
      "properties": {
        "id": {
          "type": "string",
          "format": "uint64"
        }
      },
      "title": "結果"
    },
    "protobufAny": {
      "type": "object",
      "properties": {
        "@type": {
          "type": "string"
        }
      },
      "additionalProperties": {}
    },
    "rpcStatus": {
      "type": "object",
      "properties": {
        "code": {
          "type": "integer",
          "format": "int32"
        },
        "message": {
          "type": "string"
        },
        "details": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/protobufAny"
          }
        }
      }
    }
  }
}