Create a file for your BeforeAllowTraffic Lambda function

Create a text file and save it as beforeAllowTraffic.js in the SAM-Tutorial directory.

Copy the following Node.js code into beforeAllowTraffic.js. This function executes during your deployment's BeforeAllowTraffic hook.

'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");
    				}
    			});
    		}  
    	});
    }