feat(aws-elbv2): ALB target group routing algorithms (aws#15622)

Closes aws#15160
hollanddd · Aug 26, 2021 · a670d4e · a670d4e
1 parent 45719b5
commit a670d4e
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Showing 5 changed files with 84 additions and 2 deletions.
diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-listener.ts b/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-listener.ts
@@ -5,7 +5,7 @@ import * as cxapi from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import { BaseListener, BaseListenerLookupOptions } from '../shared/base-listener';
 import { HealthCheck } from '../shared/base-target-group';
-import { ApplicationProtocol, ApplicationProtocolVersion, IpAddressType, SslPolicy } from '../shared/enums';
+import { ApplicationProtocol, ApplicationProtocolVersion, TargetGroupLoadBalancingAlgorithmType, IpAddressType, SslPolicy } from '../shared/enums';
 import { IListenerCertificate, ListenerCertificate } from '../shared/listener-certificate';
 import { determineProtocolAndPort } from '../shared/util';
 import { ListenerAction } from './application-listener-action';
@@ -367,6 +367,7 @@ export class ApplicationListener extends BaseListener implements IApplicationLis
       slowStart: props.slowStart,
       stickinessCookieDuration: props.stickinessCookieDuration,
       stickinessCookieName: props.stickinessCookieName,
+      loadBalancingAlgorithmType: props.loadBalancingAlgorithmType,
       targetGroupName: props.targetGroupName,
       targets: props.targets,
       vpc: this.loadBalancer.vpc,
@@ -887,6 +888,14 @@ export interface AddApplicationTargetsProps extends AddRuleProps {
    * @default No health check
    */
   readonly healthCheck?: HealthCheck;
+
+  /**
+   * The load balancing algorithm to select targets for routing requests.
+   *
+   * @default round_robin.
+   */
+  readonly loadBalancingAlgorithmType?: TargetGroupLoadBalancingAlgorithmType;
+
 }
 
 /**

diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-target-group.ts b/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-target-group.ts
@@ -7,7 +7,7 @@ import {
   BaseTargetGroupProps, ITargetGroup, loadBalancerNameFromListenerArn, LoadBalancerTargetProps,
   TargetGroupAttributes, TargetGroupBase, TargetGroupImportProps,
 } from '../shared/base-target-group';
-import { ApplicationProtocol, ApplicationProtocolVersion, Protocol, TargetType } from '../shared/enums';
+import { ApplicationProtocol, ApplicationProtocolVersion, Protocol, TargetType, TargetGroupLoadBalancingAlgorithmType } from '../shared/enums';
 import { ImportedTargetGroupBase } from '../shared/imported';
 import { determineProtocolAndPort } from '../shared/util';
 import { IApplicationListener } from './application-listener';
@@ -78,6 +78,13 @@ export interface ApplicationTargetGroupProps extends BaseTargetGroupProps {
    */
   readonly stickinessCookieName?: string;
 
+  /**
+   * The load balancing algorithm to select targets for routing requests.
+   *
+   * @default TargetGroupLoadBalancingAlgorithmType.ROUND_ROBIN
+   */
+  readonly loadBalancingAlgorithmType?: TargetGroupLoadBalancingAlgorithmType;
+
   /**
    * The targets to add to this target group.
    *
@@ -140,6 +147,9 @@ export class ApplicationTargetGroup extends TargetGroupBase implements IApplicat
       if (props.stickinessCookieDuration) {
         this.enableCookieStickiness(props.stickinessCookieDuration, props.stickinessCookieName);
       }
+      if (props.loadBalancingAlgorithmType) {
+        this.setAttribute('load_balancing.algorithm.type', props.loadBalancingAlgorithmType);
+      }
       this.addTarget(...(props.targets || []));
     }
   }

diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/shared/enums.ts b/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/shared/enums.ts
@@ -171,3 +171,18 @@ export enum TargetType {
    */
   LAMBDA = 'lambda',
 }
+
+/**
+ * Load balancing algorithmm type for target groups
+ */
+export enum TargetGroupLoadBalancingAlgorithmType {
+  /**
+   * round_robin
+   */
+  ROUND_ROBIN = 'round_robin',
+
+  /**
+   * least_outstanding_requests
+   */
+  LEAST_OUTSTANDING_REQUESTS = 'least_outstanding_requests',
+}
diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/listener.test.ts b/packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/listener.test.ts
@@ -866,6 +866,31 @@ describe('tests', () => {
     });
   });
 
+  test('Custom Load balancer algorithm type', () => {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.Vpc(stack, 'VPC');
+    const lb = new elbv2.ApplicationLoadBalancer(stack, 'LB', { vpc });
+    const listener = lb.addListener('Listener', { port: 80 });
+
+    // WHEN
+    listener.addTargets('Group', {
+      port: 80,
+      targets: [new FakeSelfRegisteringTarget(stack, 'Target', vpc)],
+      loadBalancingAlgorithmType: elbv2.TargetGroupLoadBalancingAlgorithmType.LEAST_OUTSTANDING_REQUESTS,
+    });
+
+    // THEN
+    expect(stack).toHaveResource('AWS::ElasticLoadBalancingV2::TargetGroup', {
+      TargetGroupAttributes: [
+        {
+          Key: 'load_balancing.algorithm.type',
+          Value: 'least_outstanding_requests',
+        },
+      ],
+    });
+  });
+
   describe('Throws with bad fixed responses', () => {
 
     test('status code', () => {

diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/target-group.test.ts b/packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/target-group.test.ts
@@ -156,6 +156,29 @@ describe('tests', () => {
     });
   });
 
+  test('Custom Load balancer algorithm type', () => {
+    // GIVEN
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'Stack');
+    const vpc = new ec2.Vpc(stack, 'VPC', {});
+
+    // WHEN
+    new elbv2.ApplicationTargetGroup(stack, 'TargetGroup', {
+      loadBalancingAlgorithmType: elbv2.TargetGroupLoadBalancingAlgorithmType.LEAST_OUTSTANDING_REQUESTS,
+      vpc,
+    });
+
+    // THEN
+    expect(stack).toHaveResource('AWS::ElasticLoadBalancingV2::TargetGroup', {
+      TargetGroupAttributes: [
+        {
+          Key: 'load_balancing.algorithm.type',
+          Value: 'least_outstanding_requests',
+        },
+      ],
+    });
+  });
+
   test('Can set a protocol version', () => {
     // GIVEN
     const app = new cdk.App();