
subaud is authored by Court Schuett (he/him). While Court is an AWS employee, opinions and statements on this blog are his own.


Court Schuett


In order to deploy a Python Lambda function with additional dependencies, we must use something that will [install those dependencies](https://packaging.python.org/en/latest/tutorials/managing-dependencies/). With NodeJS, we can use something like [`esbuild`](https://esbuild.github.io/) to do this. In a Typescript CDK, we can use npm or yarn to install this as a [development dependency](https://classic.yarnpkg.com/en/docs/dependency-types#toc-devdependencies). However, we do not have this option with a Python Lambda. To have this built during deployment, we can use the [bundlingOptions interface](https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.BundlingOptions.html).

```typescript
this.queryLambda = new Function(this, 'QueryLambda', {
  code: Code.fromAsset(path.join(__dirname, 'resources/query_lambda'), {
    bundling: {
      image: Runtime.PYTHON_3_9.bundlingImage,
      command: [
        'bash',
        '-c',
        'pip install -r requirements.txt -t /asset-output && cp -au . /asset-output',
      ],
    },
  }),
  runtime: Runtime.PYTHON_3_9,
  vpc: props.vpc,
  vpcSubnets: { subnetType: SubnetType.PRIVATE_WITH_EGRESS },
  architecture: Architecture.ARM_64,
  handler: 'index.handler',
  timeout: Duration.minutes(5),
  role: props.role,
  layers: [props.powerToolsLayer],
  environment: {
    RDS_SECRET_NAME: props.dataBase.secret?.secretName!,
  },
});
```

In [this](https://github.com/schuettc/cdk-private-rds-with-lambda/blob/main/src/lambda.ts) example from the [cdk-private-rds-with-lambda](https://github.com/schuettc/cdk-private-rds-with-lambda) repository, we can see the `QueryLambda` function is being created using `Code` from the `/resources/query_lambda` directory and bundled using a Docker image. This does require Docker desktop to be run locally or from the pipeline that is deploying this function.

When this Lambda function is deployed, `pip install` will be used with the `requirements.txt` file in the `/query_lambda` directory to create the zip file that will be uploaded as the Lambda function.

```
resources/
├── initialize_lambda/
│   ├── index.py
│   └── requirements.txt
└── query_lambda/
    ├── index.py
    └── requirements.txt
```


This article will show you how to deploy a Python Lambda function with additional dependencies using CDK

Lambda

Deploying a Python Lambda with Requirements using CDK