OpenAPITools 实践

GoCoding

发布于 2021-11-11 11:29:37

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发布于 2021-11-11 11:29:37

文章被收录于专栏：GoCodingGoCoding

OpenAPITools[1] 可以依据 REST API 描述文件，自动生成服务端桩（Stub）代码、客户端 SDK 代码，及文档等。其是社区版的 Swagger[2] ，差异可见：OpenAPI Generator vs Swagger Codegen[3]。

本文将从零开始设计和编写 API 文件，并生成 Go Gin 服务端代码，与 Python SDK 代码。更多语言或框架，也是一样操作的。

快速开始

先熟悉下工具，直接用官方 Docker 镜像生成 Petstore 样例的 Go SDK 代码：

docker run --rm -v "${PWD}:/local" openapitools/openapi-generator-cli generate \
-i https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml \
-g go \
-o /local/out/go

生成代码在当前目录的 ./out/go 。

打开 Swagger Editor[4] File > Import URL 查看 petstore.yaml API：

查看 openapi-generator-cli 用法:

docker run --rm -it \
-v "${PWD}:/local" \
--entrypoint /bin/bash \
openapitools/openapi-generator-cli

ln -s /usr/local/bin/docker-entrypoint.sh /usr/local/bin/openapi-generator
openapi-generator help
openapi-generator help generate

动手实践

设计 RESTful API

打开 Swagger Editor[5] 设计 API：

/albums
- GET - Get all albums
- POST - Create a new album
/albums/:id
- GET - Get an album by its id
- PUT - Update an album by its id
- DELETE - Delete an album by its id

完整 API 描述文件见 spec/api.yaml[6]，主要包含三部分：

头部：API 信息

openapi: 3.0.0
info:
  title: Start OpenAPITools
  description: Let's practice designing our api.
  version: 0.1.0
  license:
    name: MIT
    url: https://spdx.org/licenses/MIT.html
servers:
  - url: https://github.com/ikuokuo/start-openapitools

中间：paths 及其操作 (get, post, etc.)

paths:
  /albums/{id}:
    get:
      tags:
        - album
      summary: Get an album by its id
      operationId: getAlbum
      parameters:
        - $ref: '#/components/parameters/AlbumId'
      responses:
        200:
          description: Get success, return the album
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Album'
        404:
          description: Album not found

底部：可重用的 components，于文档里 $ref 引用

components:
  parameters:
    AlbumId:
      name: id
      in: path
      description: Album id
      required: true
      schema:
        type: string
  schemas:
    Album:
      title: Album
      type: object
      required:
        - title
        - artist
        - price
      properties:
        id:
          type: string
          format: uuid
        title:
          type: string
          maxLength: 200
          minLength: 1
        artist:
          type: string
          maxLength: 100
          minLength: 1
        price:
          type: number
          format: double
          minimum: 0.0
        created_at:
          type: string
          format: date-time
        updated_at:
          type: string
          format: date-time

具体说明，请阅读 OpenAPI Specification[7]。

在线生成代码

可以用线上服务快速生成代码：

latest stable version: https://api.openapi-generator.tech

以下则是自己动手生成的过程。

生成 Server Stub 代码

生成 Go Gin[8] 桩（Stub）代码：

docker run --rm -it \
-v "${PWD}:/local" \
--entrypoint /bin/bash \
openapitools/openapi-generator-cli

ln -s /usr/local/bin/docker-entrypoint.sh /usr/local/bin/openapi-generator

# Config Options for go-gin-server
#  https://openapi-generator.tech/docs/generators/go-gin-server
openapi-generator config-help -g go-gin-server

openapi-generator generate \
-g go-gin-server \
-i /local/spec/swagger.yaml \
-o /local/out/gin-server \
--additional-properties=packageName=startapi

生成内容：

❯ tree out/gin-server -aF --dirsfirst
out/gin-server
├── .openapi-generator/
├── api/
│   └── openapi.yaml
├── go/
│   ├── README.md
│   ├── api_album.go
│   ├── api_albums.go
│   ├── model_album.go
│   └── routers.go
├── .openapi-generator-ignore
├── Dockerfile
└── main.go

简单实现 GetAlbum 接口，位于 go/api_album.go：

// GetAlbum - Get an album by its id
func GetAlbum(c *gin.Context) {
 c.JSON(http.StatusOK, Album{
  Id:        "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  Title:     "Start OpenAPITools",
  Artist:    "GoCoding",
  Price:     0.99,
  CreatedAt: time.Now(),
  UpdatedAt: time.Now(),
 })
}

运行服务：

cd out/gin-server/
# 初始化模块
go mod init github.com/ikuokuo/start-openapitools/gin-server
go mod tidy

# 修改 `main.go` 中的 import 路径
#  sw "github.com/ikuokuo/start-openapitools/gin-server/go"
# 替换成本地路径
go mod edit -replace github.com/ikuokuo/start-openapitools/gin-server/go=./go

运行结果：

❯ go run .
2021/11/05 18:20:00 Server started
[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.

[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:   export GIN_MODE=release
 - using code:  gin.SetMode(gin.ReleaseMode)

[GIN-debug] GET    /ikuokuo/start-openapitools/ --> github.com/ikuokuo/start-openapitools/gin-server/go.Index (3 handlers)
[GIN-debug] DELETE /ikuokuo/start-openapitools/albums/:id --> github.com/ikuokuo/start-openapitools/gin-server/go.DeleteAlbum (3 handlers)
[GIN-debug] GET    /ikuokuo/start-openapitools/albums/:id --> github.com/ikuokuo/start-openapitools/gin-server/go.GetAlbum (3 handlers)
[GIN-debug] PUT    /ikuokuo/start-openapitools/albums/:id --> github.com/ikuokuo/start-openapitools/gin-server/go.PutAlbum (3 handlers)
[GIN-debug] GET    /ikuokuo/start-openapitools/albums --> github.com/ikuokuo/start-openapitools/gin-server/go.GetAlbums (3 handlers)
[GIN-debug] POST   /ikuokuo/start-openapitools/albums --> github.com/ikuokuo/start-openapitools/gin-server/go.PostAlbums (3 handlers)
[GIN-debug] Listening and serving HTTP on :8080

❯ curl http://localhost:8080/ikuokuo/start-openapitools/
Hello World!

生成 Client SDK 代码

生成 Python SDK 代码：

docker run --rm -it \
-v "${PWD}:/local" \
--entrypoint /bin/bash \
openapitools/openapi-generator-cli

ln -s /usr/local/bin/docker-entrypoint.sh /usr/local/bin/openapi-generator

# Config Options for python
#  https://openapi-generator.tech/docs/generators/python
openapi-generator config-help -g python

openapi-generator generate \
-g python \
-i /local/spec/swagger.yaml \
-o /local/out/py-sdk \
--additional-properties=packageName=startapi \
--additional-properties=library=urllib3

生成内容：

❯ tree out/py-sdk -aF --dirsfirst
out/py-sdk
├── .openapi-generator/
├── docs/
├── startapi/
│   ├── api/
│   │   ├── __init__.py
│   │   ├── album_api.py
│   │   └── albums_api.py
│   ├── apis/
│   │   └── __init__.py
│   ├── model/
│   │   ├── __init__.py
│   │   └── album.py
│   ├── models/
│   │   └── __init__.py
│   ├── __init__.py
│   ├── api_client.py
│   ├── configuration.py
│   ├── exceptions.py
│   ├── model_utils.py
│   └── rest.py
├── test/
├── .gitignore
├── .gitlab-ci.yml
├── .openapi-generator-ignore
├── .travis.yml
├── README.md
├── git_push.sh
├── requirements.txt
├── setup.cfg
├── setup.py
├── test-requirements.txt
└── tox.ini

测试 SDK 使用，调用此前实现的 GetAlbum 接口：

❯ cd out/py-sdk/
❯ python - <<EOF
from startapi import ApiClient, Configuration, apis

config = Configuration(host="http://localhost:8080/ikuokuo/start-openapitools")
with ApiClient(configuration=config) as client:
  api = apis.AlbumApi(client)
  album = api.get_album("xxxxx")
  print(album)
EOF
{'artist': 'GoCoding',
 'created_at': datetime.datetime(2021, 11, 5, 18, 30, 0, 545305, tzinfo=tzoffset(None, 28800)),
 'id': '3fa85f64-5717-4562-b3fc-2c963f66afa6',
 'price': 0.99,
 'title': 'Start OpenAPITools',
 'updated_at': datetime.datetime(2021, 11, 5, 18, 30, 0, 545305, tzinfo=tzoffset(None, 28800))}

最后

实践下来，感觉不错。很多场合，生成 SDK 就够用了。另外，生成自动化测试代码，也值得一试。

脚注

[1]OpenAPITools: https://github.com/OpenAPITools

[2]Swagger: https://swagger.io/

[3]OpenAPI Generator vs Swagger Codegen: https://openapi-generator.tech/docs/faq/#what-is-the-difference-between-swagger-codegen-and-openapi-generator

[4]Swagger Editor: https://editor.swagger.io/

[5]spec/api.yaml: https://github.com/ikuokuo/start-openapitools/blob/master/spec/api.yaml

[6]OpenAPI Specification: https://spec.openapis.org/oas/latest.html

[7]Gin: https://github.com/gin-gonic/gin

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原始发表：2021-11-05，如有侵权请联系 cloudcommunity@tencent.com 删除

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