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# 创建文件
<a name="tutorial-lambda-create-files"></a>

 要创建基础设施，必须创建以下文件：
+ `template.yml`
+ `myDateTimeFunction.js`
+ `beforeAllowTraffic.js`
+ `afterAllowTraffic.js`

**Topics**
+ [创建你的 AWS SAM 模板](tutorial-lambda-sam-template.md)
+ [为 Lambda 函数创建文件](tutorial-lambda-sam-create-lambda-function.md)
+ [为您的 BeforeAllowTraffic Lambda 函数创建一个文件](tutorial-lambda-sam-create-lambda-before-traffic.md)
+ [为您的 AfterAllowTraffic Lambda 函数创建一个文件](tutorial-lambda-sam-create-lambda-after-traffic.md)

# 创建你的 AWS SAM 模板
<a name="tutorial-lambda-sam-template"></a>

创建一个 AWS SAM 模板文件来指定基础架构中的组件。

**创建 AWS SAM 模板**

1.  创建一个名为 `SAM-Tutorial` 的目录。

1.  在 `SAM-Tutorial` 目录中创建名为 `template.yml` 的文件。

1.  将以下 YAML 代码复制到 `template.yml` 中。这是 AWS SAM 模板。

   ```
   AWSTemplateFormatVersion : '2010-09-09'
   Transform: AWS::Serverless-2016-10-31
   Description: A sample SAM template for deploying Lambda functions.
   
   Resources:
   # Details about the myDateTimeFunction Lambda function
     myDateTimeFunction:
       Type: AWS::Serverless::Function
       Properties:
         Handler: myDateTimeFunction.handler
         Runtime: nodejs18.x
   # Instructs your myDateTimeFunction is published to an alias named "live".      
         AutoPublishAlias: live
   # Grants this function permission to call lambda:InvokeFunction
         Policies:
           - Version: "2012-10-17"		 	 	 
             Statement: 
             - Effect: "Allow"
               Action: 
                 - "lambda:InvokeFunction"
               Resource: '*'
         DeploymentPreference:
   # Specifies the deployment configuration      
             Type: Linear10PercentEvery1Minute
   # Specifies Lambda functions for deployment lifecycle hooks
             Hooks:
               PreTraffic: !Ref beforeAllowTraffic
               PostTraffic: !Ref afterAllowTraffic
               
   # Specifies the BeforeAllowTraffic lifecycle hook Lambda function
     beforeAllowTraffic:
       Type: AWS::Serverless::Function
       Properties:
         Handler: beforeAllowTraffic.handler
         Policies:
           - Version: "2012-10-17"		 	 	 
   # Grants this function permission to call codedeploy:PutLifecycleEventHookExecutionStatus        
             Statement: 
             - Effect: "Allow"
               Action: 
                 - "codedeploy:PutLifecycleEventHookExecutionStatus"
               Resource:
                 !Sub 'arn:aws:codedeploy:${AWS::Region}:${AWS::AccountId}:deploymentgroup:${ServerlessDeploymentApplication}/*'
           - Version: "2012-10-17"		 	 	 
   # Grants this function permission to call lambda:InvokeFunction        
             Statement: 
             - Effect: "Allow"
               Action: 
                 - "lambda:InvokeFunction"
               Resource: !Ref myDateTimeFunction.Version
         Runtime: nodejs18.x
   # Specifies the name of the Lambda hook function      
         FunctionName: 'CodeDeployHook_beforeAllowTraffic'
         DeploymentPreference:
           Enabled: false
         Timeout: 5
         Environment:
           Variables:
             NewVersion: !Ref myDateTimeFunction.Version
             
   # Specifies the AfterAllowTraffic lifecycle hook Lambda function
     afterAllowTraffic:
       Type: AWS::Serverless::Function
       Properties:
         Handler: afterAllowTraffic.handler
         Policies:
           - Version: "2012-10-17"		 	 	 
             Statement: 
   # Grants this function permission to call codedeploy:PutLifecycleEventHookExecutionStatus         
             - Effect: "Allow"
               Action: 
                 - "codedeploy:PutLifecycleEventHookExecutionStatus"
               Resource:
                 !Sub 'arn:aws:codedeploy:${AWS::Region}:${AWS::AccountId}:deploymentgroup:${ServerlessDeploymentApplication}/*'
           - Version: "2012-10-17"		 	 	 
             Statement: 
   # Grants this function permission to call lambda:InvokeFunction          
             - Effect: "Allow"
               Action: 
                 - "lambda:InvokeFunction"
               Resource: !Ref myDateTimeFunction.Version
         Runtime: nodejs18.x
   # Specifies the name of the Lambda hook function      
         FunctionName: 'CodeDeployHook_afterAllowTraffic'
         DeploymentPreference:
           Enabled: false
         Timeout: 5
         Environment:
           Variables:
             NewVersion: !Ref myDateTimeFunction.Version
   ```

此模板指定以下内容。有关更多信息，请参阅 [AWS SAM 模板概念](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-template-basics.html)。

**一个名为 `myDateTimeFunction` 的 Lambda 函数**  
 发布此 Lambda 函数时，模板中的 `AutoPublishAlias` 行将其链接到名为 `live` 的别名。在本教程的后面部分，此函数的更新会触发部署 AWS CodeDeploy ，从而逐步将生产流量从原始版本转移到更新的版本。

**两个 Lambda 部署验证函数**  
 以下 Lambda 函数是在 CodeDeploy 生命周期挂钩期间执行的。该函数包含代码，用于验证更新的 `myDateTimeFunction` 的部署。验证测试的结果通过 `PutLifecycleEventHookExecutionStatus` API 方法传递给 CodeDeploy 。如果验证测试失败，则部署失败并回滚。  
+  `CodeDeployHook_beforeAllowTraffic` 在 `BeforeAllowTraffic` 挂钩期间运行。
+  `CodeDeployHook_afterAllowTraffic` 在 `AfterAllowTraffic` 挂钩期间运行。
这两个函数的名称以 `CodeDeployHook_` 开头。`CodeDeployRoleForLambda` 角色仅允许在 Lambda 函数中，采用以此前缀开头的名称调用 Lambda `invoke` 方法。有关更多信息，请参阅《*CodeDeploy API 参考*》中的[AppSpec AWS Lambda 部署的 “挂钩” 部分](reference-appspec-file-structure-hooks.md#appspec-hooks-lambda)和[PutLifecycleEventHookExecutionStatus](https://docs.aws.amazon.com/codedeploy/latest/APIReference/API_PutLifecycleEventHookExecutionStatus.html)。

**自动检测更新的 Lambda 函数**  
 `AutoPublishAlias` 术语指示框架检测 `myDateTimeFunction` 函数何时发生了变化，然后使用 `live` 别名进行部署。

**部署配置**  
 部署配置决定了您的 CodeDeploy应用程序将流量从原始版本的 Lambda 函数转移到新版本的速率。此模板指定预定义的部署配置 `Linear10PercentEvery1Minute`。  
 您无法在 SA AWS M 模板中指定自定义部署配置。有关更多信息，请参阅 [使用创建部署配置 CodeDeploy](deployment-configurations-create.md)。

**部署生命周期挂钩函数**  
 `Hooks` 部分指定在生命周期事件挂钩期间运行的函数。`PreTraffic` 指定在 `BeforeAllowTraffic` 挂钩期间运行的函数。`PostTraffic` 指定在 `AfterAllowTraffic` 挂钩期间运行的函数。

**Lambda 调用另一个 Lambda 函数的权限**  
 指定的`lambda:InvokeFunction`权限授予 AWS SAM 应用程序使用的角色调用 Lambda 函数的权限。当 `CodeDeployHook_beforeAllowTraffic` 和 `CodeDeployHook_afterAllowTraffic` 函数在验证测试期间调用部署的 Lambda 函数时，必须具备该权限。

# 为 Lambda 函数创建文件
<a name="tutorial-lambda-sam-create-lambda-function"></a>

本教程稍后将为更新和部署的函数创建文件。

**注意**  
 Lambda 函数可以使用 AWS Lambda支持的任何运行时。有关更多信息，请参阅 [AWS Lambda 运行时](https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html)。

**创建 Lambda 函数**

1.  创建文本文件，并以 `myDateTimeFunction.js` 文件形式保存到 `SAM-Tutorial` 目录中。

1.  将以下 Node.js 代码复制到 `myDateTimeFunction.js` 中。

   

   ```
   'use strict';
       
       exports.handler = function(event, context, callback) {
       
         if (event.body) {
           event = JSON.parse(event.body);
         }
       
         var sc; // Status code
         var result = ""; // Response payload
       
         switch(event.option) {
           case "date": 
             switch(event.period) {
               case "yesterday":
                 result = setDateResult("yesterday");
                 sc = 200;
                 break;
               case "today":
                 result = setDateResult();
                 sc = 200;
                 break;
               case "tomorrow":
                 result = setDateResult("tomorrow");
                 sc = 200;
                 break;
               default:
                 result = {
                   "error": "Must specify 'yesterday', 'today', or 'tomorrow'."
                 };
                 sc = 400;
                 break;
             }
             break;
             
       /*      Later in this tutorial, you update this function by uncommenting 
               this section. The framework created by AWS SAM detects the update 
               and triggers a deployment by CodeDeploy. The deployment shifts 
               production traffic to the updated version of this function.
               
               case "time":
               var d = new Date();
               var h = d.getHours();
               var mi = d.getMinutes();
               var s = d.getSeconds();
       
               result = {
                 "hour": h,
                 "minute": mi,
                 "second": s
               };
               sc = 200;
               break;
       */
             default:
               result = {
                 "error": "Must specify 'date' or 'time'."
               };
               sc = 400;
             break;
         }
       
         const response = {
           statusCode: sc,
           headers: { "Content-type": "application/json" },
           body: JSON.stringify( result )
         };
       
         callback(null, response);
       
         function setDateResult(option) {
       
           var d = new Date(); // Today
           var mo; // Month
           var da; // Day
           var y; // Year
       
           switch(option) {
             case "yesterday":
               d.setDate(d.getDate() - 1);
               break;
             case "tomorrow":
               d.setDate(d.getDate() + 1);
             default:
              break;
           }
       
           mo = d.getMonth() + 1; // Months are zero offset (0-11)
           da = d.getDate();
           y = d.getFullYear();
       
           result = {
             "month": mo,
             "day": da,
             "year": y
           };
       
           return result;
         }
       };
   ```

Lambda 函数返回昨天、今天或明天的日期、月份和年份。在本教程后面的部分中，您将取消注释更新函数的代码，以返回有关您指定的日期或时间的信息（例如，日期、月份和年份，或当前小时、分钟和秒）。创建的框架 AWS SAM 会检测并部署该函数的更新版本。

**注意**  
 教程中也使用了此 Lambda 函数。 AWS Cloud9 AWS Cloud9 是一个基于云的集成开发环境。有关如何在中创建、执行、更新和调试此函数的信息 AWS Cloud9，请参阅[的AWS Lambda 教程 AWS Cloud9](https://docs.aws.amazon.com/cloud9/latest/user-guide/tutorial-lambda.html)。

# 为您的 BeforeAllowTraffic Lambda 函数创建一个文件
<a name="tutorial-lambda-sam-create-lambda-before-traffic"></a>

为 `beforeAllowTraffic` 挂钩 Lambda 函数创建文件。

1.  创建文本文件，并以 `beforeAllowTraffic.js` 文件形式保存到 `SAM-Tutorial` 目录中。

1.  将以下 Node.js 代码复制到 `beforeAllowTraffic.js` 中。该函数在部署的 `BeforeAllowTraffic` 挂钩期间执行。

   ```
   'use strict';
       
       const AWS = require('aws-sdk'); 
       const codedeploy = new AWS.CodeDeploy({apiVersion: '2014-10-06'});
       var lambda = new AWS.Lambda();
       
       exports.handler = (event, context, callback) => {
       
       	console.log("Entering PreTraffic Hook!");
       	
       	// Read the DeploymentId and LifecycleEventHookExecutionId from the event payload
         var deploymentId = event.DeploymentId;
       	var lifecycleEventHookExecutionId = event.LifecycleEventHookExecutionId;
       
       	var functionToTest = process.env.NewVersion;
       	console.log("BeforeAllowTraffic hook tests started");
       	console.log("Testing new function version: " + functionToTest);
       
       	// Create parameters to pass to the updated Lambda function that
       	// include the newly added "time" option. If the function did not
       	// update, then the "time" option is invalid and function returns
       	// a statusCode of 400 indicating it failed.
       	var lambdaParams = {
       		FunctionName: functionToTest,    
       		Payload: "{\"option\": \"time\"}", 
       		InvocationType: "RequestResponse"
       	};
       
       	var lambdaResult = "Failed";
       	// Invoke the updated Lambda function.
       	lambda.invoke(lambdaParams, function(err, data) {
       		if (err){	// an error occurred
       			console.log(err, err.stack);
       			lambdaResult = "Failed";
       		}
       		else{	// successful response
       			var result = JSON.parse(data.Payload);
       			console.log("Result: " +  JSON.stringify(result));
             console.log("statusCode: " + result.statusCode);
             
             // Check if the status code returned by the updated
             // function is 400. If it is, then it failed. If 
             // is not, then it succeeded.
       			if (result.statusCode != "400"){
               console.log("Validation succeeded");
       				lambdaResult = "Succeeded";
             }
             else {
               console.log("Validation failed");
             }
       
       			// Complete the PreTraffic Hook by sending CodeDeploy the validation status
       			var params = {
       				deploymentId: deploymentId,
       				lifecycleEventHookExecutionId: lifecycleEventHookExecutionId,
       				status: lambdaResult // status can be 'Succeeded' or 'Failed'
       			};
       			
       			// Pass CodeDeploy the prepared validation test results.
       			codedeploy.putLifecycleEventHookExecutionStatus(params, function(err, data) {
       				if (err) {
       					// Validation failed.
       					console.log("CodeDeploy Status update failed");
       					console.log(err, err.stack);
       					callback("CodeDeploy Status update failed");
       				} else {
       					// Validation succeeded.
       					console.log("CodeDeploy status updated successfully");
       					callback(null, "CodeDeploy status updated successfully");
       				}
       			});
       		}  
       	});
       }
   ```

# 为您的 AfterAllowTraffic Lambda 函数创建一个文件
<a name="tutorial-lambda-sam-create-lambda-after-traffic"></a>

为 `afterAllowTraffic` 挂钩 Lambda 函数创建文件。

1.  创建文本文件，并以 `afterAllowTraffic.js` 文件形式保存到 `SAM-Tutorial` 目录中。

1.  将以下 Node.js 代码复制到 `afterAllowTraffic.js` 中。该函数在部署的 `AfterAllowTraffic` 挂钩期间执行。

   ```
   'use strict';
       
       const AWS = require('aws-sdk');
       const codedeploy = new AWS.CodeDeploy({apiVersion: '2014-10-06'});
       var lambda = new AWS.Lambda();
       
       exports.handler = (event, context, callback) => {
       
       	console.log("Entering PostTraffic Hook!");
       	
       	// Read the DeploymentId and LifecycleEventHookExecutionId from the event payload
         var deploymentId = event.DeploymentId;
       	var lifecycleEventHookExecutionId = event.LifecycleEventHookExecutionId;
       
       	var functionToTest = process.env.NewVersion;
       	console.log("AfterAllowTraffic hook tests started");
       	console.log("Testing new function version: " + functionToTest);
       
       	// Create parameters to pass to the updated Lambda function that
       	// include the original "date" parameter. If the function did not 
       	// update as expected, then the "date" option might be invalid. If 
       	// the parameter is invalid, the function returns
       	// a statusCode of 400 indicating it failed.
       	var lambdaParams = {
       		FunctionName: functionToTest,    
       		Payload: "{\"option\": \"date\", \"period\": \"today\"}", 
       		InvocationType: "RequestResponse"
       	};
       
       	var lambdaResult = "Failed";
       	// Invoke the updated Lambda function.
       	lambda.invoke(lambdaParams, function(err, data) {
       		if (err){	// an error occurred
       			console.log(err, err.stack);
       			lambdaResult = "Failed";
       		}
       		else{	// successful response
       			var result = JSON.parse(data.Payload);
       			console.log("Result: " +  JSON.stringify(result));
             console.log("statusCode: " + result.statusCode);
             
             // Check if the status code returned by the updated
             // function is 400. If it is, then it failed. If 
             // is not, then it succeeded.
       			if (result.statusCode != "400"){
               console.log("Validation of time parameter succeeded");
       				lambdaResult = "Succeeded";
             }
             else {
               console.log("Validation failed");
             }
       
       			// Complete the PostTraffic Hook by sending CodeDeploy the validation status
       			var params = {
       				deploymentId: deploymentId,
       				lifecycleEventHookExecutionId: lifecycleEventHookExecutionId,
       				status: lambdaResult // status can be 'Succeeded' or 'Failed'
       			};
       			
       			// Pass CodeDeploy the prepared validation test results.
       			codedeploy.putLifecycleEventHookExecutionStatus(params, function(err, data) {
       				if (err) {
       					// Validation failed.
       					console.log("CodeDeploy Status update failed");
       					console.log(err, err.stack);
       					callback("CodeDeploy Status update failed");
       				} else {
       					// Validation succeeded.
       					console.log("CodeDeploy status updated successfully");
       					callback(null, "CodeDeploy status updated successfully");
       				}
       			});
       		}  
       	});
       }
   ```