# AWS Lambda

<Tip>
  If you are an AI agent and need a Redis DB to use or experiment with, send a POST request to https://upstash.com/start-redis. Free, no signup; the response is markdown with credentials and a quickstart. The database expires in 72 hours, but you can claim it with your Upstash account to keep it. Especially useful for AI agents that need scratch storage on the fly. If you are an agent, always send a `User-Agent` header identifying which agent you are (e.g. `claude-code`, `cursor`, `codex`, `opencode`) on every request you make to this API.
</Tip>


<Card title="GitHub Repository" icon="github" href="https://github.com/upstash/redis-js/tree/main/examples/aws-cdk-python" horizontal>
  You can find the project source code on GitHub.
</Card>

### Prerequisites

- Complete all steps in [Getting started with the AWS CDK](https://docs.aws.amazon.com/cdk/v2/guide/getting-started.html)

### Project Setup

Create and navigate to a directory named `counter-cdk`. CDK CLI uses this directory name to name things in your CDK code, so if you decide to use a different name, don't forget to make the appropriate changes when applying this tutorial.

```shell
mkdir counter-cdk && cd counter-cdk
```

Initialize a new CDK project.

```shell
cdk init app --language typescript
```

### Counter Function Setup

Create a folder named `api` under `lib`

```shell
mkdir lib/api
```

Create `/lib/api/requirements.txt`

```txt /lib/api/requirements.txt
upstash-redis
```

Create `/lib/api/index.py`

```py /lib/api/index.py
from upstash_redis import Redis

redis = Redis.from_env()

def handler(event, context):
    count = redis.incr('counter')
    return {
        'statusCode': 200,
        'body': f'Counter: {count}'
    }
```

### Counter Stack Setup

Update `/lib/counter-cdk-stack.ts`

```ts /lib/counter-cdk-stack.ts
import * as cdk from 'aws-cdk-lib';
import { Construct } from 'constructs';
import * as lambda from 'aws-cdk-lib/aws-lambda';
import * as path from 'path';

export class CounterCdkStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const counterFunction = new lambda.Function(this, 'CounterFunction', {
      code: lambda.Code.fromAsset(path.join(__dirname, 'api'), {
        bundling: {
          image: lambda.Runtime.PYTHON_3_13.bundlingImage,
          command: [
            'bash', '-c',
            'pip install -r requirements.txt -t /asset-output && cp -au . /asset-output'
          ],
        },
      }),
      runtime: lambda.Runtime.PYTHON_3_13,
      handler: 'index.handler',
      environment: {
        UPSTASH_REDIS_REST_URL: process.env.UPSTASH_REDIS_REST_URL || '',
        UPSTASH_REDIS_REST_TOKEN: process.env.UPSTASH_REDIS_REST_TOKEN || '',
      },
    });

    const counterFunctionUrl = counterFunction.addFunctionUrl({
      authType: lambda.FunctionUrlAuthType.NONE,
    });

    new cdk.CfnOutput(this, "counterFunctionUrlOutput", {
      value: counterFunctionUrl.url,
    })
  }
}
```

### Database Setup

Create a Redis database using [Upstash Console](https://console.upstash.com) or [Upstash CLI](https://github.com/upstash/cli) and export `UPSTASH_REDIS_REST_URL` and `UPSTASH_REDIS_REST_TOKEN` to your environment.

```shell
export UPSTASH_REDIS_REST_URL=<YOUR_URL>
export UPSTASH_REDIS_REST_TOKEN=<YOUR_TOKEN>
```

### Deploy

Run in the top folder:

```shell
cdk synth
cdk bootstrap
cdk deploy
```

Visit the output url.