Using aws elasticache with redshiftdata

Question

Pulumi · Accepted Answer

AWS ElastiCache is a fully managed in-memory data store and cache service by Amazon Web Services (AWS). While AWS Redshift is a fully managed, petabyte-scale data warehouse service. ElastiCache can support Redshift in scenarios such as when you need to cache complex query results for quick access or maintain session state information that can be accessed by Redshift queries.

Here, I'll describe how to set up an ElastiCache cluster, and then I'll show you how you might use the AWS SDK within a Lambda function, triggered by an API Gateway, to interact with both ElastiCache (for caching) and Redshift. Note, however, that the details of the query and the logic for caching are highly application-specific and cannot be fully covered without more context.

First, let's start with setting up an ElastiCache cluster using AWS's Redis engine. We will use Pulumi's AWS Classic package (`aws`) for creating the ElastiCache cluster. Following that, we will set up an AWS Lambda function that queries the data in Redshift and caches it in the ElastiCache.

```typescript
import * as aws from "@pulumi/aws";

// Create an Elasticache Cluster
const cluster = new aws.elasticache.Cluster("myCluster", {
    engine: "redis", // Choose "redis" or "memcached" based on your needs
    nodeType: "cache.m4.large",
    numCacheNodes: 1,
    parameterGroupName: "default.redis3.2",
    engineVersion: "3.2.10",
    port: 6379, // Default Redis port
});

// Now, let's consider how you would use AWS Lambda to interact with Redshift and ElastiCache.
// For this, you need an IAM role and policy that allows Lambda to interact with Redshift and ElastiCache.

// Create an IAM role and attach policies that provide access to Redshift and Elasticache
const lambdaRole = new aws.iam.Role("lambdaRole", {
    assumeRolePolicy: {
        Version: "2012-10-17",
        Statement: [{
            Action: "sts:AssumeRole",
            Effect: "Allow",
            Principal: {
                Service: "lambda.amazonaws.com",
            },
        }],
    },
});

// Attaching policy for Redshift data access
const redshiftDataAccess = new aws.iam.RolePolicyAttachment("redshiftDataAccess", {
    role: lambdaRole.name,
    policyArn: "arn:aws:iam::aws:policy/AmazonRedshiftDataFullAccess",
});

// Attaching policy for ElastiCache data access
const elasticCacheDataAccess = new aws.iam.RolePolicyAttachment("elasticCacheDataAccess", {
    role: lambdaRole.name,
    policyArn: "arn:aws:iam::aws:policy/AmazonElastiCacheFullAccess",
});

// Create a Lambda function that will execute our logic
const lambdaFunction = new aws.lambda.Function("myFunction", {
    code: new pulumi.asset.AssetArchive({
        ".": new pulumi.asset.FileArchive("./lambda"), // Directory with your Lambda code
    }),
    role: lambdaRole.arn,
    handler: "index.handler", // File and method name of your Lambda handler
    runtime: aws.lambda.NodeJS12dXRuntime, // Use the appropriate runtime for your application
    environment: {
        variables: {
            REDSHIFT_CLUSTER_IDENTIFIER: "your-redshift-cluster-identifier",
            REDSHIFT_DB_NAME: "your-redshift-db-name",
            REDSHIFT_USER: "your-redshift-username",
            ELASTICACHE_ENDPOINT: cluster.cacheNodes.apply(nodes => nodes[0].address),
        },
    },
});

// Create an API Gateway to trigger the Lambda function
const api = new aws.apigatewayv2.Api("myApi", {
    protocolType: "HTTP",
});

// Integration between API Gateway and Lambda
const integration = new aws.apigatewayv2.Integration("myIntegration", {
    apiId: api.id,
    integrationType: "AWS_PROXY",
    integrationUri: lambdaFunction.arn,
    payloadFormatVersion: "2.0",
});

// Create a default route that invokes the Lambda function
const route = new aws.apigatewayv2.Route("defaultRoute", {
    apiId: api.id,
    routeKey: "$default",
    target: integration.id.apply(id => `integrations/${id}`),
});

// Deploy the API
const deployment = new aws.apigatewayv2.Deployment("myDeployment", {
    apiId: api.id,
    // Ensures that changes to the API or Lambda function will result in a new deployment
    triggers: {
        redeployment: pulumi.all([api.id, lambdaFunction.arn]).apply(([apiId, lambdaArn]) => `${apiId}:${lambdaArn}`),
    },
});

new aws.apigatewayv2.Stage("devStage", {
    apiId: api.id,
    name: "dev",
    deploymentId: deployment.id,
    autoDeploy: true,
});

// Export the URL of the API Gateway to access the Lambda function
export const apiUrl = api.apiEndpoint;
```

In this example, the cluster is a simple, single-node Redis cluster suitable for small to medium-sized workloads. This code snippet sets up an ElastiCache cluster, creates IAM roles with the necessary permissions, sets up a Lambda function, and an API Gateway with a route and stage to trigger the Lambda.

The hypothetical Lambda function (handler code not provided here) would perform the necessary logic to query Redshift and cache the results in ElastiCache Redis. The Lambda function's environment variables are set to include connection parameters for Redshift and the ElastiCache endpoint.

For the Redis connection within the Lambda function, you'll need to use a Redis client that is compatible with your Lambda's runtime and programming language.

Keep in mind that to execute this program, you will also need a Pulumi stack and AWS credentials configured properly. Additionally, you will need to provide the code for the Lambda function in the designated Lambda deployment package directory (`./lambda` in the example), including application logic, querying Redshift, and caching to Redis.

Lastly, you can find more information about the [`aws.elasticache.Cluster`](https://www.pulumi.com/registry/packages/aws/api-docs/elasticache/cluster/) and [`aws.lambda.Function`](https://www.pulumi.com/registry/packages/aws/api-docs/lambda/function/) in the Pulumi AWS documentation.