OpenApi自动生成client

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本文已参与「新人创作礼」活动,一起开启掘金创作之路。

前言

之前没有觉得OpenApi有什么特别了不得的,直到参加了花旗银行的一次面试,对方部门老总对OpenApi是非常重视,认为可以极大提升效率;后来在eBay,随着微服务化的推行,应用之间RESTful调用指数级增长,应用内调用接口的代码占了很大一部分,复用程度不高,比如一个基础应用A被10个上层应用调用,各写各的后果如下:

  • 10个应用有的用okHttp有的用apache http,不统一
  • 单元测试覆盖率要达到80%,意味着相同功能加10倍UT
  • 缺乏重试、异常处理等机制

后来试用了OpenApi,将如上10个应用的代码,代替为OpenApi生成的jar包(jar包可以统一管理,10个应用引入即可),采用的技术统一,UT只要一份,代码质量有保证!


OpenApi和swagger

OpenApi解析swagger的接口的规程,自动生成java类库,非常方便!

网易链接口调用关系.md 里面用到了自己编写的okHttpClient,但是如果能够自动生成,岂不是很方便? swagger.md 原理是利用swagger.json,里面有详细的返回的类及哪些接口

20190924: 跑通了整体流程,最大改动:submitTime原来是offsetTime类型的,后来我改为string还是不过,后来干脆取消对这个字段的读取,就通过了;另外发现一个jobType的问题,是haowen在qm上遗漏了,已经fix了


具体操作 hands-on

  1. 先把swagger.json 下载下来
  2. 在运行
$ java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -i workswagger.json -g java -o /var/tmp/javaClient4Workflow

上传到ebay的qa库中,小窍门是1.0-SNAPSHOT,否则报错

[INFO] --- maven-deploy-plugin:2.7:deploy (default-deploy) @ openapi-workflow-client ---
Downloading: https://ebaycentral.qa.ebay.com/content/repositories/snapshots/com/ebay/marketing/opclients/openapi-workflow-client/1.0-SNAPSHOT/maven-metadata.xml
Uploading: https://ebaycentral.qa.ebay.com/content/repositories/snapshots/com/ebay/marketing/opclients/openapi-workflow-client/1.0-SNAPSHOT/openapi-workflow-client-1.0-20190918.062345-1.jar
Uploaded: https://ebaycentral.qa.ebay.com/content/repositories/snapshots/com/ebay/marketing/opclients/openapi-workflow-client/1.0-SNAPSHOT/openapi-workflow-client-1.0-20190918.062345-1.jar (102 KB at 45.3 KB/sec)
Uploading: https://ebaycentral.qa.ebay.com/content/repositories/snapshots/com/ebay/marketing/opclients/openapi-workflow-client/1.0-SNAPSHOT/openapi-workflow-client-1.0-20190918.062345-1.pom
Uploaded: https://ebaycentral.qa.ebay.com/content/repositories/snapshots/com/ebay/marketing/opclients/openapi-workflow-client/1.0-SNAPSHOT/openapi-workflow-client-1.0-20190918.062345-1.pom (11 KB at 15.3 KB/sec)


平常做spring-boot项目在服务间相互调用时一般都是RestTemplate,有了这个就不用了,可以生成client端的jar包,直接调用jar包中的方法就会进行服务调用

命令

git clone https://github.com/openapitools/openapi-generator.git
cd openapi-generator
mvn clean install
java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate \
  -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml \
  -l jaxrs-cxf-client \
  -o /var/tmp/openapi-generator/jaxrs-cxf-client

openapi-generator-cli help 用list命令尝试

config-help

meta

validate (先验证一下给的petstore的例子)

openapi-generator validate -i petstore-v3.0.yaml
$ java -jar openapi-generator-cli.jar help
usage: openapi-generator-cli <command> [<args>]

The most commonly used openapi-generator-cli commands are:
    config-help Config help for chosen lang
    generate Generate code with the specified generator.
    help Display help information
    list Lists the available generators
    meta MetaGenerator. Generator for creating a new template set and configuration for Codegen. The output will be based on the language you specify, and includes default templates to include.
    validate Validate specification
    version Show version information