Question

我正在尝试以RxJS方式调用AWS Lambda函数：

invokeLambda(): Observable<string> {
  const lambda = new AWS.Lambda({region: environment.region, apiVersion: "2015-03-31"});
  const invoke$ = (functionName, payload, invocationType = "RequestResponse") => {
  return Observable.bindNodeCallback(lambda.invoke)();
};

return invoke$(environment.functionName, {}).map((result: InvocationResponse) => JSON.parse(<string>result.Payload));

}

然而，当我尝试：

this.myService.invokeLambda().subscribe(() => { dosomething(); }

我收到错误：

page.html:5 ERROR TypeError: this.makeRequest is not a function
at svc.(anonymous function)

我做错了什么？

Answer 1

我建议创建一个Facade，用于将http请求分派给作为AWS Lambda代理的Amazon API Gateway。您可以将AWS SDK事件处理程序包装在observable中。在以下示例中，我使用rxjs搜索标识池名称，并确定该名称是否存在于我的AWS账户中的Amazon Cognito联合身份标识池列表中。我将Lambda函数与AWS Step Functions集成在一起，以增强rxjs“next”通道功能。 Rxjs，AWS Lambda和AWS Step Functions重试任务状态定义允许我通过cognitoidentity.listIdentityPools名称的分页“继续”Amazon Cognito联合身份标识池名称存在搜索。步骤函数在使用rxjs时启用lambda函数的递归执行。通过将从第一次执行lambda函数返回的分页标记作为参数返回到下一个通过步骤函数状态递归执行lambda函数。即

exports.handler = (event, context, callback) => {

  AWS.config.region = "...";

  AWS.config.apiVersions = {
    cognitoidentity: '2014-06-30'
  };

  var cognitoidentity = new AWS.CognitoIdentity();

  var params = {
    MaxResults: 1,
    get NextToken() {
      if (event.NextToken == null || undefined) {
        return null;
      } else {
        return event.NextToken;
      }
    }
  };

  var eventResult = {
    identityPoolName: '',
    identityPoolId: '',
    NextToken: '',
    NextState: '',
    error: '',
    errorReason: ''
  };

 function listIdentityPoolsObservable(params) {
   return Rx.Observable.create(observer => {

    cognitoidentity.listIdentityPools(params)
      .on('success', function(response) {
        observer.next(response.data);
      })
      .on('error', function(error, response) {
        observer.error(error);
      })
      .on('complete', function(response) {
        if (response.error) {
          observer.error(response.error)
        } else {
          observer.complete(response);
        }
      }).send();
    });
  };

  const source$ = listIdentityPoolsObservable(params)
    .share()
    .observeOn(Rx.Scheduler.asap);

  const identityPoolsSource$ = source$.map(x => {
    return x.IdentityPools;
  })
  .flatMap(x => {
    return x;
  })
  .filter( x => x.IdentityPoolName === event.identityPoolName)
  .map(x => {
    if (x.IdentityPoolName === event.identityPoolName) {
      var dataArr = [x.IdentityPoolName, x.IdentityPoolId];
      return dataArr;
    }
  })
  .defaultIfEmpty(false);

  const nextTokenSource$ = source$
    .filter(x => x.NextToken != null || undefined)
    .map(x => {
      if (x.NextToken != null || undefined) {
        return x.NextToken;  
      }
     })
     .defaultIfEmpty(false);

  var identityAndToken = Rx.Observable
    .forkJoin(identityPoolsSource$, nextTokenSource$)
    .subscribe(x => {
      //conditional statements...
      callback(null, eventResult);
    });

  function ExceptionExistence(eventResult) {
    this.name = eventResult.errorName;
    this.errorReason = eventResult.errorReason;
  };
  ExceptionExistence.prototype = new Error();

};

如何使用Observable.bindNodeCallback（lambda.invoke）调用AWS Lambda

1 个答案: