aws(学习笔记第十七课)

• SQS Amazon Simple Queue Service服务

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学习内容：

• 使用SQS Amazon Simple Queue Service服务
• 整体代码（nodejs的通常工程）
• 代码动作

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1. 使用SQS Amazon Simple Queue Service服务

1. 利用应用程序来学习SQS
   
   • 创建S3

     $ aws s3 mb s3://urs2png-20241211-finlay
     $ aws s3 website s3://urs2png-20241211-finlay --index-document index.html --error-document error.html
     

   • 创建SQS

     aws sqs create-queue --queue-name url2png
     

     
2. 整体代码（nodejs的通常工程）
   • config.json
     将QueueUrl替换成上面创建的SQS
     将Bucket替换成上面创建的S3 bucket的名字

     {"QueueUrl": "https://sqs.ap-northeast-1.amazonaws.com/081353481087/url2png","Bucket": "urs2png-20241211-finlay"
     }
     

   • package.json 定义依赖关系

     {"dependencies": {"aws-sdk": "2.1.18","node-uuid": "1.4.3","node-webshot": "1.0.4","phantomjs-prebuilt": "2.1.16"},"private": true
     }
     

   • index.js (生产者 producer)
     it send url of png to sqs on aws.

     var AWS = require('aws-sdk');
     var uuid = require('node-uuid');
     var config = require('./config.json');
     var sqs = new AWS.SQS({"region": "ap-northeast-1"
     });if (process.argv.length !== 3) {console.log('URL missing');process.exit(1);
     }var id = uuid.v4();
     var body = {"id": id,"url": process.argv[2]
     };sqs.sendMessage({"MessageBody": JSON.stringify(body),"QueueUrl": config.QueueUrl
     }, function(err) {if (err) {console.log('error', err);} else {console.log('PNG will be soon available at http://' + config.Bucket + '.s3-website-us-east-1.amazonaws.com/' + id + '.png');}
     });
     

   • worker.js 消费者（consumer）
     receive message of sqs on aws every 1 second.

     var fs = require('fs');
     var AWS = require('aws-sdk');
     var webshot = require('node-webshot');
     var config = require('./config.json');
     var sqs = new AWS.SQS({"region": "us-east-1"
     });
     var s3 = new AWS.S3({"region": "us-east-1"
     });function acknowledge(message, cb) {var params = {"QueueUrl": config.QueueUrl,"ReceiptHandle": message.ReceiptHandle};sqs.deleteMessage(params, cb);
     }function process(message, cb) {var body = JSON.parse(message.Body);var file = body.id + '.png';webshot(body.url, file, function(err) {if (err) {cb(err);} else {fs.readFile(file, function(err, buf) {if (err) {cb(err);} else {var params = {"Bucket": config.Bucket,"Key": file,"ACL": "public-read","ContentType": "image/png","Body": buf};s3.putObject(params, function(err) {if (err) {cb(err);} else {fs.unlink(file, cb);}});}});}});
     }function receive(cb) {var params = {"QueueUrl": config.QueueUrl,"MaxNumberOfMessages": 1,"VisibilityTimeout": 120,"WaitTimeSeconds": 10};sqs.receiveMessage(params, function(err, data) {if (err) {cb(err);} else {if (data.Messages === undefined) {cb(null, null);} else {cb(null, data.Messages[0]);}}});
     }function run() {receive(function(err, message) {if (err) {throw err;} else {if (message === null) {console.log('nothing to do');setTimeout(run, 1000);} else {console.log('process');process(message, function(err) {if (err) {throw err;} else {acknowledge(message, function(err) {if (err) {throw err;} else {console.log('done');setTimeout(run, 1000);}});}});}}});
     }run();
     

3. 代码动作

1. 安装nodejs
   由于一些包的原因，这个nodejs程序只能运行在nodejs@v11.15.0，因此事先下载。
   nodejsv11.15.0
   
2. 执行npm install

   npm install
   

3. 准备图片
   示例图片URL
4. 运行程序
   • 首先运行work.js监视aws sqs

     node work.js
     

     
   • 之后运行index.js

     node index.js "https://pics1.baidu.com/feed/f9dcd100baa1cd11d2771efce7c9a6f8c1ce2d0c.jpeg@f_auto?token=e630acf36ce316be5abcb2652d6971b3&s=110AA3F04A32B6C842AFE716030040DF"
     

     
     可以看到work.js这边显示done，表明已经接收到url的message，处理成文件之后传送到了S3 bucket。
   • 最后检查S3 bucket