amazon-web-services - 为 Golang Lambda 功能单元测试模拟 AWS API 网关请求和 DynamoDB

Question

设置

• Windows 10
• 去v1.10.3
• aws cli v1.16.67

我想做什么

测试使用 golang 编写的 AWS Lambda 函数。该函数接受来自 API 网关 的请求，然后使用 DynamoDB 执行一些操作。以下大部分内容摘自 this文章(我是 Go 的新手)

package main

import (
    "encoding/json"
    "log"
    "net/http"
    "os"
    "regexp"

    "github.com/aws/aws-lambda-go/events"
    "github.com/aws/aws-lambda-go/lambda"
)

var uuidRegexp = regexp.MustCompile(`\b[0-9a-f]{8}\b-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-\b[0-9a-f]{12}\b`)
var errorLogger = log.New(os.Stderr, "ERROR ", log.Llongfile)

type job struct {
    ID                string `json:"id"`
    ClientID          string `json:"clientId"`
    Title             string `json:"title"`
    Count             int    `json:"count"`
}

// CreateJobCommand manages interactions with DynamoDB
func CreateJobCommand(req events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {

    if req.Headers["Content-Type"] != "application/json" {
        return clientError(http.StatusNotAcceptable) //406
    }

    newJob := new(job)
    err := json.Unmarshal([]byte(req.Body), newJob)

    // Ensure request has deserialized correctly
    if err != nil {
        return clientError(http.StatusUnprocessableEntity) //422
    }

    // Validate ID and ClientID attributes match RegEx pattern
    if !uuidRegexp.MatchString(newJob.ID) || !uuidRegexp.MatchString(newJob.ClientID) {
        return clientError(http.StatusBadRequest)
    }

    // Mandatory field check
    if newJob.Title == "" {
        return clientError(http.StatusBadRequest)
    }

    // Put item in database
    err = putItem(newJob) // putItem is defined in another file
    if err != nil {
        return serverError(err)
    }

    return events.APIGatewayProxyResponse{
        StatusCode: 201,
    }, nil
}

// Add a helper for handling errors. This logs any error to os.Stderr
// and returns a 500 Internal Server Error response that the AWS API
// Gateway understands.
func serverError(err error) (events.APIGatewayProxyResponse, error) {
    errorLogger.Println(err.Error())

    return events.APIGatewayProxyResponse{
        StatusCode: http.StatusInternalServerError,
        Body:       http.StatusText(http.StatusInternalServerError),
    }, nil
}

// Similarly add a helper for send responses relating to client errors.
func clientError(status int) (events.APIGatewayProxyResponse, error) {
    return events.APIGatewayProxyResponse{
        StatusCode: status,
        Body:       http.StatusText(status),
    }, nil
}

func putItem(job *job) error {

    // create an aws session
    sess := session.Must(session.NewSession(&aws.Config{
        Region:   aws.String("us-east-1"),
        Endpoint: aws.String("http://localhost:8000"),
    }))

    // create a dynamodb instance
    db := dynamodb.New(sess)

    // marshal the job struct into an aws attribute value object
    jobAVMap, err := dynamodbattribute.MarshalMap(job)
    if err != nil {
        return err
    }

    input := &dynamodb.PutItemInput{
        TableName: aws.String("TEST_TABLE"),
        Item:      jobAVMap,
    }

    _, err = db.PutItem(input)
    return err
}

func main() {
    lambda.Start(CreateJobCommand)
}

问题

我想写一组单元测试来测试这个功能。在我看来，我需要做的第一件事是模拟 API 网关请求和 DynamoDB 表，但我不知道该怎么做。

问题

1. 是否有我应该使用的模拟框架？
2. 如果有人知道任何对这个主题有帮助的文档，请指出一下好吗？ (我的 Google 技能还没有显示出来)

谢谢

Answer 1

我这样做的方法是在指针接收器中传递依赖项(因为处理程序的签名是有限的)并使用接口(interface)。每个服务都有相应的接口(interface)。对于 dynamodb-dynamodbiface。所以在你的情况下 lambda 本身你需要定义一个接收器:

type myReceiver struct {
    dynI dynamodbiface.DynamoDBAPI
}

将 main 更改为:

func main() {

    sess := session.Must(session.NewSession(&aws.Config{
        Region: aws.String("your region")},
    ))

    inj := myReceiver{
        dyn: dynamodb.New(sess),
    }
    lambda.Start(inj.CreateJobCommand)

将处理程序更改为

func (inj *myReceiver) CreateJobCommand(req events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error)

所有对 dynamodb API 的后续调用都需要通过接口(interface):

    _, err = inj.dynI.PutItem(input)

然后在您的测试函数中您需要模拟响应:

 type mockDynamo struct {
    dynI dynamodbiface.DynamoDBAPI
    dynResponse dynamodb.PutItemOutput

} 

func (mq mockDynamo) PutItem (in *dynamodb.PutItemInput) (*dynamodb.PutItemOutput , error) {
    return &dynamodv.dynResponse, nil
}


        m1: = mockDynamo {

            dynResponse : dynamodb.PutItemOutput{
            
            some mocked output
        } 


        inj := myReceiver{
            dyn: m1,         
        }

     inj.CreateJobCommand(some mocked data  for APIGateway request)