feat(lambda): add support for ephemeral storage

packages/@aws-cdk/aws-lambda/README.md

@@ -710,6 +710,18 @@ const fn = new lambda.Function(this, 'MyLambda', {
 });
 ```
 
+## Ephemeral Storage
+
+You can configure ephemeral storage (/tmp) between 512 MB and 10,240 MB, and you can now control the amount of ephemeral storage a function gets for reading or writing data, allowing you to use AWS Lambda for ETL jobs, ML inference, or other data-intensive workloads.
+
+```ts
+const fn = new lambda.Function(this, 'MyFunction', {
+  runtime: lambda.Runtime.NODEJS_12_X,
+  handler: 'index.handler',
+  code: lambda.Code.fromAsset(path.join(__dirname, 'lambda-handler')),
+  ephemeralStorageSize: 1024,
+});
+```
 
 ## Singleton Function
 

packages/@aws-cdk/aws-lambda/lib/function.ts

@@ -95,6 +95,13 @@ export interface FunctionOptions extends EventInvokeConfigOptions {
    */
   readonly memorySize?: number;
 
+  /**
+   * The size of the function’s /tmp directory in MB.
+   *
+   * @default 512
+   */
+  readonly ephemeralStorageSize?: number;
+
   /**
    * Initial policy statements to add to the created Lambda Role.
    *
@@ -743,6 +750,10 @@ export class Function extends FunctionBase {
     }
     this._architecture = props.architecture ?? (props.architectures && props.architectures[0]);
 
+    if (props.ephemeralStorageSize && (props.ephemeralStorageSize < 512 || props.ephemeralStorageSize > 10240)) {
+      throw new Error('Ephemeral storage size must be between 512 and 10240 MB.');
+    }
+
     const resource: CfnFunction = new CfnFunction(this, 'Resource', {
       functionName: this.physicalName,
       description: props.description,
@@ -763,6 +774,7 @@ export class Function extends FunctionBase {
       // Token, actually *modifies* the 'environment' map.
       environment: Lazy.uncachedAny({ produce: () => this.renderEnvironment() }),
       memorySize: props.memorySize,
+      ephemeralStorage: this.buildEphemeralStorage(props),
       vpcConfig: this.configureVpc(props),
       deadLetterConfig: this.buildDeadLetterConfig(dlqTopicOrQueue),
       tracingConfig: this.buildTracingConfig(props),
@@ -1128,6 +1140,16 @@ Environment variables can be marked for removal when used in Lambda@Edge by sett
     }
   }
 
+  private buildEphemeralStorage(props: FunctionProps) {
+    if (props.ephemeralStorageSize === undefined) {
+      return undefined;
+    }
+
+    return {
+      size: props.ephemeralStorageSize,
+    };
+  }
+
   private buildTracingConfig(props: FunctionProps) {
     if (props.tracing === undefined || props.tracing === Tracing.DISABLED) {
       return undefined;

packages/@aws-cdk/aws-lambda/test/function.test.ts

@@ -2487,6 +2487,16 @@ describe('function', () => {
   });
 });
 
+test('throws if ephemeral storage size is out of bound', () => {
+  const stack = new cdk.Stack();
+  expect(() => new lambda.Function(stack, 'MyLambda', {
+    code: new lambda.InlineCode('foo'),
+    handler: 'bar',
+    runtime: lambda.Runtime.NODEJS_14_X,
+    ephemeralStorageSize: 511,
+  })).toThrow(/Ephemeral storage size must be between 512 and 10240 MB./);
+});
+
 function newTestLambda(scope: constructs.Construct) {
   return new lambda.Function(scope, 'MyLambda', {
     code: new lambda.InlineCode('foo'),