即将换项目，据说新项目是servless架构。看有空提前准备点AWS Lambda知识
关于SAM的定义：
AWS Serverless Application Model (SAM) is an open-source framework for building serverless applications
什么是Serverless Application
还是从AWS的文档中来看serverless application的定义如下：
A serverless application is a combination of Lambda functions, event sources, and other resources that work together to perform tasks. Note that a serverless application is more than just a Lambda function—it can include additional resources such as APIs, databases, and event source mappings.
其实关于serverless，意即其不需要server的，不过需要多说一句的是其实不需要申请任何AWS服务器的。
什么是AWS Lambda
AWS文档中对AWS Lambda开门见山的介绍：
AWS Lambda is a compute service that lets you run code without provisioning or managing servers.
为什么要使用AWS Lambda呢?AWS 文档也是相当的直接：
You pay only for the compute time you consume - there is no charge when your code is not running.
看样子用AWS Lambda是不需要服务器的，也是比较省钱的。
什么时候使用AWS Lambda呢？
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Run your code in response to events.
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Run your code in response to HTTP requests using Amazon API Gateway
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Invoke your code using API calls made using AWS SDKs
AWS文档也给出了一些events的场景：
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Changes to data in an Amazon S3 bucket
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Changes to data in an Amazon DynamoDB table
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Run your code in response to HTTP requests using Amazon API Gateway
AWS SAM CLI
安装
SAM CLI依赖于docker，所以不管当前环境是Linux, Windows还是MacOS，首先要安装好docker。
笔者使用的是MacOS，且已经安装了brew神器，所以安装AWS CLI非常简单:
brew tap aws/tap
brew install aws-sam-cli
安装完成后，就可以直接使用sam命令了，如sam -version。
如果你希望在Windows环境安装SAM CLI，请参考官方文档 Installing the AWS SAM CLI on Windows
如果你希望在Linux环境安装SAM CLI，请参考官方文档 Installing the AWS SAM CLI on Linux