feat(elbv2): support pathpattern array (#6558)

* Adding support for an array of path patterns for application listener rule config. Closes #6497 * Introduce `pathPatterns` prop for listener rule * Introduce `pathPatterns` prop for listener rule * Deperecate `pathPattern`. Co-authored-by: Derk Schooltink <[email protected]> Co-authored-by: Rico Huijbers <[email protected]> Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
aws · Mar 9, 2020 · c3ee413 · c3ee413
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diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/README.md b/packages/@aws-cdk/aws-elasticloadbalancingv2/README.md
@@ -73,23 +73,28 @@ listener.addFixedResponse('Fixed', {
 #### Conditions
 
 It's possible to route traffic to targets based on conditions in the incoming
-HTTP request. Path- and host-based conditions are supported. For example,
-the following will route requests to the indicated AutoScalingGroup
-only if the requested host in the request is `example.com`:
+HTTP request. Path- and host-based conditions are supported. For example, the
+following will route requests to the indicated AutoScalingGroup only if the
+requested host in the request is either for `example.com/ok` or
+`example.com/path`:
 
 ```ts
 listener.addTargets('Example.Com Fleet', {
     priority: 10,
+    pathPatterns: ['/ok', '/path'],
     hostHeader: 'example.com',
     port: 8080,
     targets: [asg]
 });
 ```
 
-`priority` is a required field when you add targets with conditions. The lowest
-number wins.
+A target with a condition contains either `pathPatterns` or `hostHeader`, or
+both. If both are specified, both conditions must be met for the requests to
+be routed to the given target. `priority` is a required field when you add
+targets with conditions. The lowest number wins.
 
-Every listener must have at least one target without conditions.
+Every listener must have at least one target without conditions, which is
+where all requests that didn't match any of the conditions will be sent.
 
 ### Defining a Network Load Balancer
 

diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-listener-rule.ts b/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-listener-rule.ts
@@ -54,13 +54,21 @@ export interface BaseApplicationListenerRuleProps {
   /**
    * Rule applies if the requested path matches the given path pattern
    *
-   * May contain up to three '*' wildcards.
-   *
    * @see https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-listeners.html#path-conditions
-   *
    * @default - No path condition.
+   * @deprecated Use `pathPatterns` instead.
    */
   readonly pathPattern?: string;
+
+  /**
+   * Rule applies if the requested path matches any of the given patterns.
+   *
+   * Paths may contain up to three '*' wildcards.
+   *
+   * @see https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-listeners.html#path-conditions
+   * @default - No path conditions.
+   */
+  readonly pathPatterns?: string[];
 }
 
 /**
@@ -169,8 +177,9 @@ export class ApplicationListenerRule extends cdk.Construct {
   constructor(scope: cdk.Construct, id: string, props: ApplicationListenerRuleProps) {
     super(scope, id);
 
-    if (!props.hostHeader && !props.pathPattern) {
-      throw new Error(`At least one of 'hostHeader' or 'pathPattern' is required when defining a load balancing rule.`);
+    const hasPathPatterns = props.pathPatterns || props.pathPattern;
+    if (!props.hostHeader && !hasPathPatterns) {
+      throw new Error(`At least one of 'hostHeader', 'pathPattern' or 'pathPatterns' is required when defining a load balancing rule.`);
     }
 
     const possibleActions: Array<keyof ApplicationListenerRuleProps> = ['targetGroups', 'fixedResponse', 'redirectResponse'];
@@ -195,8 +204,13 @@ export class ApplicationListenerRule extends cdk.Construct {
     if (props.hostHeader) {
       this.setCondition('host-header', [props.hostHeader]);
     }
-    if (props.pathPattern) {
-      this.setCondition('path-pattern', [props.pathPattern]);
+
+    if (hasPathPatterns) {
+      if (props.pathPattern && props.pathPatterns) {
+        throw new Error('Both `pathPatterns` and `pathPattern` are specified, specify only one');
+      }
+      const pathPattern = props.pathPattern ? [props.pathPattern] : props.pathPatterns;
+      this.setCondition('path-pattern', pathPattern);
     }
 
     (props.targetGroups || []).forEach(this.addTargetGroup.bind(this));

diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-listener.ts b/packages/@aws-cdk/aws-elasticloadbalancingv2/lib/alb/application-listener.ts
@@ -209,6 +209,7 @@ export class ApplicationListener extends BaseListener implements IApplicationLis
         listener: this,
         hostHeader: props.hostHeader,
         pathPattern: props.pathPattern,
+        pathPatterns: props.pathPatterns,
         priority: props.priority,
         targetGroups: props.targetGroups
       });
@@ -252,6 +253,7 @@ export class ApplicationListener extends BaseListener implements IApplicationLis
     this.addTargetGroups(id, {
       hostHeader: props.hostHeader,
       pathPattern: props.pathPattern,
+      pathPatterns: props.pathPatterns,
       priority: props.priority,
       targetGroups: [group],
     });
@@ -480,9 +482,7 @@ class ImportedApplicationListener extends Resource implements IApplicationListen
    * At least one TargetGroup must be added without conditions.
    */
   public addTargetGroups(id: string, props: AddApplicationTargetGroupsProps): void {
-    if ((props.hostHeader !== undefined || props.pathPattern !== undefined) !== (props.priority !== undefined)) {
-      throw new Error(`Setting 'pathPattern' or 'hostHeader' also requires 'priority', and vice versa`);
-    }
+    checkAddRuleProps(props);
 
     if (props.priority !== undefined) {
       // New rule
@@ -562,10 +562,22 @@ export interface AddRuleProps {
    * Requires that priority is set.
    *
    * @see https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-listeners.html#path-conditions
-   *
    * @default No path condition
+   * @deprecated Use `pathPatterns` instead.
    */
   readonly pathPattern?: string;
+
+  /**
+   * Rule applies if the requested path matches any of the given patterns.
+   *
+   * May contain up to three '*' wildcards.
+   *
+   * Requires that priority is set.
+   *
+   * @see https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-listeners.html#path-conditions
+   * @default - No path condition.
+   */
+  readonly pathPatterns?: string[];
 }
 
 /**
@@ -667,7 +679,7 @@ export interface AddRedirectResponseProps extends AddRuleProps, RedirectResponse
 }
 
 function checkAddRuleProps(props: AddRuleProps) {
-  if ((props.hostHeader !== undefined || props.pathPattern !== undefined) !== (props.priority !== undefined)) {
+  if ((props.hostHeader !== undefined || props.pathPattern !== undefined || props.pathPatterns !== undefined) !== (props.priority !== undefined)) {
     throw new Error(`Setting 'pathPattern' or 'hostHeader' also requires 'priority', and vice versa`);
   }
 }
diff --git a/packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/test.listener.ts b/packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/test.listener.ts
@@ -937,6 +937,61 @@ export = {
 
     test.done();
   },
+
+  'Can add multiple path patterns to listener rule'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.Vpc(stack, 'Stack');
+    const lb = new elbv2.ApplicationLoadBalancer(stack, 'LB', { vpc });
+
+    // WHEN
+    const listener = lb.addListener('Listener', {
+      port: 443,
+      certificateArns: ['cert1', 'cert2'],
+      defaultTargetGroups: [new elbv2.ApplicationTargetGroup(stack, 'Group', { vpc, port: 80 })]
+    });
+
+    listener.addTargets('Target1', {
+      priority: 10,
+      pathPatterns: ['/test/path/1', '/test/path/2']
+    });
+
+    // THEN
+    expect(stack).to(haveResource('AWS::ElasticLoadBalancingV2::ListenerRule', {
+      Priority: 10,
+      Conditions: [
+        {
+          Field: 'path-pattern',
+          Values: ['/test/path/1', '/test/path/2']
+        }
+      ]
+    }));
+
+    test.done();
+  },
+
+  'Cannot add pathPattern and pathPatterns to listener rule'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.Vpc(stack, 'Stack');
+    const lb = new elbv2.ApplicationLoadBalancer(stack, 'LB', { vpc });
+
+    // WHEN
+    const listener = lb.addListener('Listener', {
+      port: 443,
+      certificateArns: ['cert1', 'cert2'],
+      defaultTargetGroups: [new elbv2.ApplicationTargetGroup(stack, 'Group', { vpc, port: 80 })]
+    });
+
+    // THEN
+    test.throws(() => listener.addTargets('Target1', {
+      priority: 10,
+      pathPatterns: ['/test/path/1', '/test/path/2'],
+      pathPattern: '/test/path/3'
+    }), Error, `At least one of 'hostHeader', 'pathPattern' or 'pathPatterns' is required when defining a load balancing rule.`);
+
+    test.done();
+  },
 };
 
 class ResourceWithLBDependency extends cdk.CfnResource {