feat(lambda): event-source maxBatchingWindow property

packages/@aws-cdk/aws-lambda-event-sources/lib/dynamodb.ts

@@ -1,29 +1,17 @@
 import dynamodb = require('@aws-cdk/aws-dynamodb');
 import lambda = require('@aws-cdk/aws-lambda');
+import {StreamEventSource, StreamEventSourceProps} from './stream';
 
-export interface DynamoEventSourceProps {
-  /**
-   * The largest number of records that AWS Lambda will retrieve from your event
-   * source at the time of invoking your function. Your function receives an
-   * event with all the retrieved records.
-   *
-   * Valid Range: Minimum value of 1. Maximum value of 1000.
-   *
-   * @default 100
-   */
-  readonly batchSize?: number;
-
-  /**
-   * Where to begin consuming the DynamoDB stream.
-   */
-  readonly startingPosition: lambda.StartingPosition;
+export interface DynamoEventSourceProps extends StreamEventSourceProps {
 }
 
 /**
  * Use an Amazon DynamoDB stream as an event source for AWS Lambda.
  */
-export class DynamoEventSource implements lambda.IEventSource {
-  constructor(private readonly table: dynamodb.Table, private readonly props: DynamoEventSourceProps) {
+export class DynamoEventSource extends StreamEventSource {
+  constructor(private readonly table: dynamodb.Table, props: DynamoEventSourceProps) {
+    super(props);
+
     if (this.props.batchSize !== undefined && (this.props.batchSize < 1 || this.props.batchSize > 1000)) {
       throw new Error(`Maximum batch size must be between 1 and 1000 inclusive (given ${this.props.batchSize})`);
     }
@@ -34,11 +22,9 @@ export class DynamoEventSource implements lambda.IEventSource {
       throw new Error(`DynamoDB Streams must be enabled on the table ${this.table.node.path}`);
     }
 
-    target.addEventSourceMapping(`DynamoDBEventSource:${this.table.node.uniqueId}`, {
-      batchSize: this.props.batchSize || 100,
-      eventSourceArn: this.table.tableStreamArn,
-      startingPosition: this.props.startingPosition
-    });
+    target.addEventSourceMapping(`DynamoDBEventSource:${this.table.node.uniqueId}`,
+      this.enrichMappingOptions({eventSourceArn: this.table.tableStreamArn})
+    );
 
     this.table.grantStreamRead(target);
     dynamodb.Table.grantListStreams(target);

packages/@aws-cdk/aws-lambda-event-sources/lib/kinesis.ts

@@ -1,41 +1,27 @@
 import kinesis = require('@aws-cdk/aws-kinesis');
 import lambda = require('@aws-cdk/aws-lambda');
+import {StreamEventSource, StreamEventSourceProps} from './stream';
 
-export interface KinesisEventSourceProps {
-  /**
-   * The largest number of records that AWS Lambda will retrieve from your event
-   * source at the time of invoking your function. Your function receives an
-   * event with all the retrieved records.
-   *
-   * Valid Range: Minimum value of 1. Maximum value of 10000.
-   *
-   * @default 100
-   */
-  readonly batchSize?: number;
-
-  /**
-   * Where to begin consuming the Kinesis stream.
-   */
-  readonly startingPosition: lambda.StartingPosition;
+export interface KinesisEventSourceProps extends StreamEventSourceProps {
 }
 
 /**
  * Use an Amazon Kinesis stream as an event source for AWS Lambda.
  */
-export class KinesisEventSource implements lambda.IEventSource {
-  constructor(readonly stream: kinesis.IStream, private readonly props: KinesisEventSourceProps) {
+export class KinesisEventSource extends StreamEventSource {
+  constructor(readonly stream: kinesis.IStream, props: KinesisEventSourceProps) {
+    super(props);
+
     if (this.props.batchSize !== undefined && (this.props.batchSize < 1 || this.props.batchSize > 10000)) {
       throw new Error(`Maximum batch size must be between 1 and 10000 inclusive (given ${this.props.batchSize})`);
     }
   }
 
   public bind(target: lambda.IFunction) {
-    target.addEventSourceMapping(`KinesisEventSource:${this.stream.node.uniqueId}`, {
-      batchSize: this.props.batchSize || 100,
-      startingPosition: this.props.startingPosition,
-      eventSourceArn: this.stream.streamArn,
-    });
+    target.addEventSourceMapping(`KinesisEventSource:${this.stream.node.uniqueId}`,
+      this.enrichMappingOptions({eventSourceArn: this.stream.streamArn})
+    );
 
     this.stream.grantRead(target);
   }
-}
+}

packages/@aws-cdk/aws-lambda-event-sources/lib/stream.ts

@@ -0,0 +1,52 @@
+import lambda = require('@aws-cdk/aws-lambda');
+import {Duration} from '@aws-cdk/core';
+
+/**
+ * @internal
+ */
+export interface StreamEventSourceProps {
+  /**
+   * The largest number of records that AWS Lambda will retrieve from your event
+   * source at the time of invoking your function. Your function receives an
+   * event with all the retrieved records.
+   *
+   * Valid Range: Minimum value of 1. Maximum value of 10000.
+   *
+   * @default 100
+   */
+  readonly batchSize?: number;
+
+  /**
+   * Where to begin consuming the stream.
+   */
+  readonly startingPosition: lambda.StartingPosition;
+
+  /**
+   * The maximum amount of time to gather records before invoking the function.
+   * Maximum of Duration.minutes(5)
+   *
+   * @default Duration.seconds(0)
+   */
+  readonly maxBatchingWindow?: Duration;
+}
+
+/**
+ * Use an stream as an event source for AWS Lambda.
+ *
+ * @internal
+ */
+export abstract class StreamEventSource implements lambda.IEventSource {
+  protected constructor(protected readonly props: StreamEventSourceProps) {
+  }
+
+  public abstract bind(_target: lambda.IFunction): void;
+
+  protected enrichMappingOptions(options: lambda.EventSourceMappingOptions): lambda.EventSourceMappingOptions {
+    return {
+      ...options,
+      batchSize: this.props.batchSize || 100,
+      startingPosition: this.props.startingPosition,
+      maxBatchingWindow: this.props.maxBatchingWindow,
+    };
+  }
+}

packages/@aws-cdk/aws-lambda-event-sources/test/test.dynamo.ts

@@ -172,4 +172,63 @@ export = {
 
     test.done();
   },
+
+  'specific maxBatchingWindow'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const fn = new TestFunction(stack, 'Fn');
+    const table = new dynamodb.Table(stack, 'T', {
+      partitionKey: {
+        name: 'id',
+        type: dynamodb.AttributeType.STRING
+      },
+      stream: dynamodb.StreamViewType.NEW_IMAGE
+    });
+
+    // WHEN
+    fn.addEventSource(new sources.DynamoEventSource(table, {
+      maxBatchingWindow: cdk.Duration.minutes(2),
+      startingPosition: lambda.StartingPosition.LATEST
+    }));
+
+    // THEN
+    expect(stack).to(haveResource('AWS::Lambda::EventSourceMapping', {
+      "EventSourceArn": {
+        "Fn::GetAtt": [
+          "TD925BC7E",
+          "StreamArn"
+        ]
+      },
+      "FunctionName":  {
+        "Ref": "Fn9270CBC0"
+      },
+      "MaximumBatchingWindowInSeconds": 120,
+      "StartingPosition": "LATEST"
+    }));
+
+    test.done();
+  },
+
+  'throws if maxBatchingWindow > 300 seconds'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const fn = new TestFunction(stack, 'Fn');
+    const table = new dynamodb.Table(stack, 'T', {
+      partitionKey: {
+        name: 'id',
+        type: dynamodb.AttributeType.STRING
+      },
+      stream: dynamodb.StreamViewType.NEW_IMAGE
+    });
+
+    // THEN
+    test.throws(() =>
+      fn.addEventSource(new sources.DynamoEventSource(table, {
+        maxBatchingWindow: cdk.Duration.seconds(301),
+        startingPosition: lambda.StartingPosition.LATEST
+      })), /maxBatchingWindow cannot be over 300 seconds/);
+
+    test.done();
+  },
+
 };

packages/@aws-cdk/aws-lambda-event-sources/test/test.kinesis.ts

@@ -123,4 +123,34 @@ export = {
 
     test.done();
   },
+
+  'specific maxBatchingWindow'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const fn = new TestFunction(stack, 'Fn');
+    const stream = new kinesis.Stream(stack, 'S');
+
+    // WHEN
+    fn.addEventSource(new sources.KinesisEventSource(stream, {
+      maxBatchingWindow: cdk.Duration.minutes(2),
+      startingPosition: lambda.StartingPosition.LATEST
+    }));
+
+    // THEN
+    expect(stack).to(haveResource('AWS::Lambda::EventSourceMapping', {
+      "EventSourceArn": {
+        "Fn::GetAtt": [
+          "S509448A1",
+          "Arn"
+        ]
+      },
+      "FunctionName":  {
+        "Ref": "Fn9270CBC0"
+      },
+      "MaximumBatchingWindowInSeconds": 120,
+      "StartingPosition": "LATEST"
+    }));
+
+    test.done();
+  },
 };

packages/@aws-cdk/aws-lambda/lib/event-source-mapping.ts

@@ -37,7 +37,15 @@ export interface EventSourceMappingOptions {
    *
    * @default - Required for Amazon Kinesis and Amazon DynamoDB Streams sources.
    */
-  readonly startingPosition?: StartingPosition
+  readonly startingPosition?: StartingPosition;
+
+  /**
+   * The maximum amount of time to gather records before invoking the function.
+   * Maximum of Duration.minutes(5)
+   *
+   * @default Duration.seconds(0)
+   */
+  readonly maxBatchingWindow?: cdk.Duration;
 }
 
 export interface EventSourceMappingProps extends EventSourceMappingOptions {
@@ -63,12 +71,17 @@ export class EventSourceMapping extends Resource {
   constructor(scope: cdk.Construct, id: string, props: EventSourceMappingProps) {
     super(scope, id);
 
+    if (props.maxBatchingWindow && props.maxBatchingWindow.toSeconds() > 300) {
+      throw new Error(`maxBatchingWindow cannot be over 300 seconds, got ${props.maxBatchingWindow.toSeconds()}`);
+    }
+
     new CfnEventSourceMapping(this, 'Resource', {
       batchSize: props.batchSize,
       enabled: props.enabled,
       eventSourceArn: props.eventSourceArn,
       functionName: props.target.functionName,
       startingPosition: props.startingPosition,
+      maximumBatchingWindowInSeconds: props.maxBatchingWindow && props.maxBatchingWindow.toSeconds(),
     });
   }
 }