Serverless CloudFormation config for Elasticache Redis server

s-function.json

{
	"name": "showConfig",
	"runtime": "nodejs",
	"description": "Returns Redis host and Serverless stage",
	"handler": "redis/showConfig/handler.handler",
	"timeout": 6,
	"memorySize": 256,
	"custom": {
		"optimize": true
	},
    "environment": {
        "STAGE": "${stage}",
        "REDIS_HOST": "${redisHost}"
    },
	"endpoints": [{
		"path": "redis/showConfig",
		"method": "POST",
		"type": "AWS",
		"requestParameters": {},
		"requestTemplates": "$${apiRequestTemplate}",
		"responses": {
			"default": {
				"statusCode": "200"
			}
		}
	}]
}

s-resources-cf.json

{
    "AWSTemplateFormatVersion": "2010-09-09",
    "Description": "The AWS CloudFormation template for this Serverless application's resources outside of Lambdas and Api Gateway",
    "Resources": {
        "IamRoleLambda": {
            "Type": "AWS::IAM::Role",
            "Properties": {
                "AssumeRolePolicyDocument": {
                    "Version": "2012-10-17",
                    "Statement": [
                        {
                            "Effect": "Allow",
                            "Principal": {
                                "Service": [
                                    "lambda.amazonaws.com"
                                ]
                            },
                            "Action": [
                                "sts:AssumeRole"
                            ]
                        }
                    ]
                },
                "Path": "/"
            }
        },
        "IamPolicyLambda": {
            "Type": "AWS::IAM::Policy",
            "Properties": {
                "PolicyName": "${stage}-${project}-lambda",
                "PolicyDocument": {
                    "Version": "2012-10-17",
                    "Statement": [
                        {
                            "Effect": "Allow",
                            "Action": [
                                "logs:CreateLogGroup",
                                "logs:CreateLogStream",
                                "logs:PutLogEvents"
                            ],
                            "Resource": "arn:aws:logs:${region}:*:*"
                        },
                        {
                            "Effect": "Allow",
                            "Action": [
                                "logs:CreateLogGroup",
                                "logs:CreateLogStream",
                                "logs:PutLogEvents",
                                "ec2:CreateNetworkInterface",
                                "ec2:DescribeNetworkInterfaces",
                                "ec2:DeleteNetworkInterface"
                            ],
                            "Resource": "*"
                        }
                    ]
                },
                "Roles": [
                    {
                        "Ref": "IamRoleLambda"
                    }
                ]
            }
        },
        "RedisCluster" : {
            "Type": "AWS::ElastiCache::CacheCluster",
            "Properties": {
                "CacheNodeType": "cache.t2.micro",
                "CacheSecurityGroupNames": ["default"],
                "Engine": "redis",
                "NumCacheNodes": "1"
            }
        }
    },
    "Outputs": {
        "IamRoleArnLambda": {
            "Description": "ARN of the lambda IAM role",
            "Value": {
                "Fn::GetAtt": [
                    "IamRoleLambda",
                    "Arn"
                ]
            }
        },
        "RedisHost": {
            "Description": "ARN of the lambda IAM role",
            "Value": {
                "Fn::GetAtt": [
                    "RedisCluster",
                    "RedisEndpoint.Address"
                ]
            }
        }
    }
}

Thanks so much for this! Super useful!

Weird how the "RedisHost" in the Outputs for CloudFormation has to be "redisHost" when defining the env variable. I noticed this after quite a while trying to get it to work. Maybe add a note at the top of your gist?

Thanks again!

Hi there, how can I use this for Replication Groups?

"ElasticacheReplicationGroup": {
      "Type": "AWS::ElastiCache::ReplicationGroup",
      "Properties": {
        "ReplicationGroupDescription" : "Redis replication group",
        "NumCacheClusters" : "2",
        "Engine" : "redis",
        "CacheNodeType" : "cache.t2.micro",
        "AutoMinorVersionUpgrade" : "true",
        "AutomaticFailoverEnabled" : "false"
      }
    }

I cannot use "CacheSecurityGroupNames": ["default"] because I get _

Your accounts support the EC2-VPC platform, which does not support ElastiCache security groups. Instead, specify VPC security group IDs.

_

Also, I tried exactly the RedisCluster version on the this Gist but I can't connect to Redis within the Lambda, can anyone please tell if this is currently working??

Did you manage to get it working?