aws apigateway 使用restapi集成lambda

参考资料

• 代理集成，https://docs.aws.amazon.com/zh_cn/apigateway/latest/developerguide/api-gateway-create-api-as-simple-proxy-for-lambda.html
• 非代理集成，https://docs.aws.amazon.com/zh_cn/apigateway/latest/developerguide/getting-started-lambda-non-proxy-integration.html

从上一篇文章中我们知道，apigateway集成lambda有两种方式

• 代理集成，集成所有api方法，将请求直接发往lambda函数，无需对api进行重新部署
• 非代理集成，见下文

restapi代理集成lambda

创建lambda函数，取名GetStartedLambdaProxyIntegration，执行角色保持默认即可

下面是官方问demo函数，我们精简一下把校验的逻辑去掉看看（测试没必要）

'use strict';export const handler = async (event) => {// 查看事件console.log(event)let name = "you";let city = 'World';let time = 'day';let day = '';let responseCode = 200;// 打印请求console.log("request: " + JSON.stringify(event));// 解析请求参数let name = event.name === undefined ? 'you' : event.name;let city = event.city === undefined ? 'World' : event.city;let time = event.time === undefined ? 'morning' : event.time;// 解析请求体let body = JSON.parse(event.body).timelet greeting = `Good ${time}, ${name} of ${city}.`;let responseBody = {message: greeting,input: event};// 构造响应let response = {statusCode: responseCode,headers: {"x-custom-header" : "my custom header value"},body: JSON.stringify(responseBody)};// 打印响应console.log("response: " + JSON.stringify(response))// 返回响应return response;
};

创建restapi由于resapi是资源和方法的组合，因此有以下

• 资源 /helloworld，不要勾选代理资源

  代理集成和代理资源不是一个概念
  

• 方法 ANY（捕获所有），勾选lambda代理集成

  

注意这里创建方法并集成lambda后会提示自动为lambda函数添加权限

注意：如果手动创建lambda函数，并不会自动添加这个权限，即apigateway没有权限调用lambda

我们把这个权限删掉查看调用结果

创建完毕后需要手动新型部署，创建并选择test阶段，每个阶段都是一个apigateway的快照

图示实际上就是方法/集成，请求/响应之间的转换，我们可以更精细的设置这些阶段的参数。可以点击测试

在访问控制方面，我们有以下选择

• 匿名访问

• 身份访问

  • apigateway基于资源的策略
  • iam策略
  • lambda授权方
  • cognito身份池

终端请求测试，在非中国区是可以直接请求的

// 未备案无法匿名访问
$ curl https://y2o41dcif7.execute-api.cn-north-1.amazonaws.com.cn/test/helloworld
{"Message":null}// 访问错误方法
{"message":"No method found matching route helloworl for http method GET."}// 没有凭证
{"message": "Missing Authentication Token"}// 内部错误，可能是apigate无法访问lambda，可以在apigateway控制台测试
{"message": "Internal server error"}// 不知道为什么始终403
$ awscurl --service execute-api -X GET --region cn-north-1 --profile admin "https://y2o41dcif7.execute-api.cn-north-1.amazonaws.com.cn/test/helloworld?name=John&city=Seattle"
{"Message":null}
Traceback (most recent call last):File "/home/ec2-user/.local/bin/awscurl", line 8, in <module>sys.exit(main())File "/home/ec2-user/.local/lib/python3.7/site-packages/awscurl/awscurl.py", line 521, in maininner_main(sys.argv[1:])File "/home/ec2-user/.local/lib/python3.7/site-packages/awscurl/awscurl.py", line 515, in inner_mainresponse.raise_for_status()File "/home/ec2-user/.local/lib/python3.7/site-packages/requests/models.py", line 1021, in raise_for_statusraise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 403 Client Error: Forbidden for url: https://y2o41dcif7.execute-api.cn-north-1.amazonaws.com.cn/test/helloworld?name=John&city=Seattle

后来发现iam认证需要在方法上单独开启，之后仍旧需要部署一下

重新请求

$ awscurl --service execute-api -X GET --region cn-north-1 --profile admin "https://y2o41dcif7.execute-api.cn-north-1.amazonaws.com.cn/test/helloworld?name=John&city=Seattle"
{"message":"Good day, John of Seattle.","input":{"resource":"/helloworld","path":"/helloworld","httpMethod":"GET","headers":{"Accept":"application/xml","Accept-Encoding":"gzip, deflate","Content-Type":"application/json","Host":"y2o41dcif7.execute-api.cn-north-1.amazonaws.com.cn","User-Agent":"python-requests/2.28.1","x-amz-content-sha256":"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855","x-amz-date":"20230305T055851Z","X-Amzn-Trace-Id":"Root=1-64042f9b-79563b285727810b2a19fe26","X-Forwarded-For":"52.81.227.226","X-Forwarded-Port":"443","X-Forwarded-Proto":"https"},"multiValueHeaders":{"Accept":["application/xml"],"Accept-Encoding":["gzip, deflate"],"Content-Type":["application/json"],"Host":["y2o41dcif7.execute-api.cn-north-1.amazonaws.com.cn"],"User-Agent":["python-requests/2.28.1"],"x-amz-content-sha256":["e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"],"x-amz-date":["20230305T055851Z"],"X-Amzn-Trace-Id":["Root=1-64042f9b-79563b285727810b2a19fe26"],"X-Forwarded-For":["52.81.227.226"],"X-Forwarded-Port":["443"],"X-Forwarded-Proto":["https"]},"queryStringParameters":{"city":"Seattle","name":"John"},"multiValueQueryStringParameters":{"city":["Seattle"],"name":["John"]},"pathParameters":null,"stageVariables":null,"requestContext":{"resourceId":"wwo9nn","resourcePath":"/helloworld","httpMethod":"GET","extendedRequestId":"BSxgZHB2hTIFSmw=","requestTime":"05/Mar/2023:05:58:51 +0000","path":"/test/helloworld","accountId":"xxxxxxxxxxx","protocol":"HTTP/1.1","stage":"test","domainPrefix":"y2o41dcif7","requestTimeEpoch":1677995931863,"requestId":"38db2a8b-b5d7-4230-a3e4-3851ceada31b","identity":{"cognitoIdentityPoolId":null,"accountId":"xxxxxxxxxxx","cognitoIdentityId":null,"caller":"AIDAQRIBWRJKPC2O5EBGY","sourceIp":"52.81.227.226","principalOrgId":"o-vut99korpx","accessKey":"AKIAQRIBWRJKK45B727U","cognitoAuthenticationType":null,"cognitoAuthenticationProvider":null,"userArn":"arn:aws-cn:iam::xxxxxxxxxxx:user/zhaojie","userAgent":"python-requests/2.28.1","user":"AIDAQRIBWRJKPC2O5EBGY"},"domainName":"y2o41dcif7.execute-api.cn-north-1.amazonaws.com.cn","apiId":"y2o41dcif7"},"body":null,"isBase64Encoded":false}}

在cwlogs中查看lambda函数的请求事件如下

• 请求参数和请求体
• 请求发起人，控制台上为aws-internal/3 aws-sdk-java

{resource: '/helloworld',path: '/helloworld',httpMethod: 'GET',headers: null,multiValueHeaders: null,queryStringParameters: { city: 'Seattle' },multiValueQueryStringParameters: { city: [ 'Seattle' ] },pathParameters: null,stageVariables: null,requestContext: {resourceId: 'wwo9nn',resourcePath: '/helloworld',httpMethod: 'GET',extendedRequestId: 'BSlRoGtiBTIFkGQ=',requestTime: '05/Mar/2023:04:35:22 +0000',path: '/helloworld',accountId: 'xxxxxxxxxxx',protocol: 'HTTP/1.1',stage: 'test-invoke-stage',domainPrefix: 'testPrefix',requestTimeEpoch: 1677990922153,requestId: '0754dbf7-c943-41cd-8cd0-7f23c24f72e3',identity: {cognitoIdentityPoolId: null,cognitoIdentityId: null,apiKey: 'test-invoke-api-key',principalOrgId: null,cognitoAuthenticationType: null,userArn: 'arn:aws-cn:iam::xxxxxxxxxxx:user/xxxxxx',apiKeyId: 'test-invoke-api-key-id',userAgent: 'aws-internal/3 aws-sdk-java/1.12.407 Linux/5.4.231-145.341.amzn2int.x86_64 OpenJDK_64-Bit_Server_VM/25.362-b10 java/1.8.0_362 vendor/Oracle_Corporation cfg/retry-mode/standard',accountId: 'xxxxxxxxxxx',caller: 'xxxxxxx',sourceIp: 'test-invoke-source-ip',accessKey: 'xxxxxxx',cognitoAuthenticationProvider: null,user: 'AIDAQxxxxxEBGY'},domainName: 'testPrefix.testDomainName',apiId: 'y2o41dcif7'},body: null,isBase64Encoded: false
}

restapi非代理集成lambda

创建名为GetStartedLambdaIntegration的函数

• 相比代理集成，非代理集成的lambda只从集成请求体中获取输入。函数可以返回任何 JSON 对象、字符串、数字、布尔值甚至二进制 blob 的输出
• 代理集成的 Lambda 函数可以从任何请求数据获取输入，但必须返回特定 JSON 对象
• 对于自定义集成需要创建映射模板完成前后端数据的转换

这里官方文档给出的是老版本lambda的写法。。。很离谱

'use strict';
var days = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];            
var times = ['morning', 'afternoon', 'evening', 'night', 'day'];exports.handler = async (event)=> {console.log(event);// Parse the input for the name, city, time and day property valueslet name = event.name === undefined ? 'you' : event.name;let city = event.city === undefined ? 'World' : event.city;let time = event.time ? 'morning' : event.time;let day = days.indexOf(event.day)<0 ? null : event.day;// Generate a greetinglet greeting = 'Good ' + time + ', ' + name + ' of ' + city + '. ';if (day) greeting += 'Happy ' + day + '!';// Log the greeting to CloudWatchconsole.log('Hello: ', greeting);let response = {"greeting": greeting};// Return a greeting to the callerreturn response; 
};

创建restapi非代理集成lambda

• 步骤和代理集成一致，但是需要开启cors预检

• 创建方法时，不要勾选lambda代理集成

• 设置2个必须参数，time为查询参数，day为请求头参数

  

创建如下model完成请求体数据映射

• schema是固定写法

• 内容类型为application/json

我们已经知道非代理集成只能从集成请求体中获取参数，因此需要对方法请求创建model映射

然后在集成请求中对参数进行解析

• time和day来自于请求参数
• callername来自于根路径

总结一下

• model定义了客户端请求规范
• mapping定义了如何从方法请求构造集成请求

在控制台测试请求

我们看看lambda函数的事件输入

• 看起来很简单实际上是apigateway帮我们处理了
• 优点是lambda函数不需要承担解析任务
• 缺点是每次修改数据模型都需要重新部署apigateway

{ city: 'Seattle', time: 'morning', day: 'Wednesday', name: 'John' 
}

在终端进行请求

$ awscurl --service execute-api -X POST  --region cn-north-1 "https://qzoqsj2lp4.execute-api.cn-north-1.amazonaws.com.cn/test/city?name=John&city=Seattle"                                                     
{"greeting":"Good ,  of Seattle. "}