Add Redis cache

Author: mnapoli

src/cache/Redis.ts

@@ -0,0 +1,47 @@
+import { CfnCacheCluster, CfnCacheClusterProps, CfnSubnetGroup } from 'aws-cdk-lib/aws-elasticache';
+import { Names } from 'aws-cdk-lib';
+import { Port, SecurityGroup } from 'aws-cdk-lib/aws-ec2';
+import { Construct } from 'constructs';
+import { VpcForServerlessApp } from '../vpc/VpcForServerlessApp';
+
+export type RedisProps = Partial<CfnCacheClusterProps> & {
+    vpc: VpcForServerlessApp;
+};
+
+export class Redis extends CfnCacheCluster {
+    constructor(scope: Construct, id: string, props: RedisProps) {
+        const securityGroup = new SecurityGroup(scope, `${id}SecurityGroup`, {
+            vpc: props.vpc,
+            description: 'Security group for Redis',
+            allowAllOutbound: false,
+            allowAllIpv6Outbound: false,
+        });
+
+        const stackId = Names.uniqueResourceName(securityGroup, {
+            maxLength: 100,
+        });
+        const subnetGroup = new CfnSubnetGroup(scope, `${id}SubnetGroup`, {
+            cacheSubnetGroupName: `${stackId}${id}SubnetGroup`,
+            description: 'Subnet group for Redis',
+            // Isolated subnets don't have a route to the internet (unlike private), this is what we want
+            subnetIds: props.vpc.isolatedSubnets.map((subnet) => subnet.subnetId),
+        });
+
+        props.vpc.appSecurityGroup.connections.allowTo(
+            securityGroup,
+            Port.tcp(props.port ?? 6379),
+            'Allow Lambda functions to connect to Redis'
+        );
+
+        super(scope, id, {
+            engine: 'redis',
+            cacheNodeType: 'cache.t3.micro',
+            numCacheNodes: 1,
+            vpcSecurityGroupIds: [securityGroup.securityGroupId],
+            cacheSubnetGroupName: subnetGroup.cacheSubnetGroupName,
+            ...props,
+        });
+
+        this.addDependsOn(subnetGroup);
+    }
+}

src/index.ts

@@ -1,7 +1,9 @@
+import { Redis } from './cache/Redis';
 import { ConsoleFunction } from './function/ConsoleFunction';
 import { PhpFpmFunction, PhpFpmFunctionProps } from './function/PhpFpmFunction';
 import { PhpFunction, PhpFunctionProps } from './function/PhpFunction';
 import { packagePhpCode } from './package';
+import { VpcForServerlessApp } from './vpc/VpcForServerlessApp';
 
 export {
     PhpFunction,
@@ -10,4 +12,6 @@ export {
     PhpFpmFunctionProps,
     ConsoleFunction,
     packagePhpCode,
+    VpcForServerlessApp,
+    Redis,
 };

test/cache/Redis.test.ts

@@ -0,0 +1,15 @@
+import { describe, expect, it } from 'vitest';
+import { cleanupTemplate, compileTestStack } from '../helper';
+import { Redis, VpcForServerlessApp } from '../../src';
+
+describe('Redis', () => {
+    it('builds', () => {
+        const template = compileTestStack((stack) => {
+            new Redis(stack, 'Redis', {
+                vpc: new VpcForServerlessApp(stack, 'Vpc'),
+            });
+        }).toJSON();
+
+        expect(cleanupTemplate(template).Resources).toMatchSnapshot();
+    });
+});