fix(aws-elbv2): add dependency on internet gateway (#1284)

Internet-facing load balancers can only be created once the VPC's
Internet Gateway has been created, otherwise creation is an error.

Usually the gateway is speedy enough to create so that this lack of a
dependency doesn't show, but to be correct we still need to add it.

Fixes #1129.

ALSO IN THIS CHANGE

* Add a script to visualize dependencies in a CloudFormation template
  (by converting to .dot).
* Add a script to run integration tests in parallel.

CONTRIBUTING.md

@@ -169,6 +169,27 @@ $ nodeunit test/test.*.js
 <BOOM>
 ```
 
+### Running integration tests in parallel
+
+Integration tests may take a long time to complete. We can speed this up by running them in parallel
+in different regions.
+
+```shell
+# Install GNU parallel (may require uninstall 'moreutils' if you have it)
+$ apt-get install parallel
+$ brew install parallel
+
+$ scripts/run-integ-parallel @aws-cdk/aws-ec2 @aws-cdk/aws-autoscaling ...
+```
+
+### Visualizing dependencies in a CloudFormation Template
+
+Use GraphViz with `template-deps-to-dot`:
+
+```shell
+$ cdk -a some.app.js synth | $awscdk/scripts/template-deps-to-dot | dot -Tpng > deps.png
+```
+
 ### Build Documentation Only
 
 The CDK documentation source is hosted under [`./docs/src`](./docs/src). Module reference documentation is gathered
@@ -200,7 +221,7 @@ Guidelines:
    updates to automatically be picked up.
  * Make sure `package-lock.json` files are included in your commit.
 
-### Finding Dependency Cycles
+### Finding dependency cycles between packages
 
 You can use `find-cycles` to print a list of internal dependency cycles:
 

packages/@aws-cdk/aws-autoscaling/lib/util.ts

@@ -9,4 +9,4 @@ export class LazyDependable implements cdk.IDependable {
   public get dependencyElements(): cdk.IDependable[] {
     return this.dependableSource.dependencyElements;
   }
-}
+}

packages/@aws-cdk/aws-autoscaling/test/integ.amazonlinux2.expected.json

@@ -67,9 +67,6 @@
     },
     "VPCPublicSubnet1DefaultRoute91CEF279": {
       "Type": "AWS::EC2::Route",
-      "DependsOn": [
-        "VPCVPCGW99B986DC"
-      ],
       "Properties": {
         "RouteTableId": {
           "Ref": "VPCPublicSubnet1RouteTableFEE4B781"
@@ -78,7 +75,10 @@
         "GatewayId": {
           "Ref": "VPCIGWB7E252D3"
         }
-      }
+      },
+      "DependsOn": [
+        "VPCVPCGW99B986DC"
+      ]
     },
     "VPCPublicSubnet1EIP6AD938E8": {
       "Type": "AWS::EC2::EIP",
@@ -158,9 +158,6 @@
     },
     "VPCPublicSubnet2DefaultRouteB7481BBA": {
       "Type": "AWS::EC2::Route",
-      "DependsOn": [
-        "VPCVPCGW99B986DC"
-      ],
       "Properties": {
         "RouteTableId": {
           "Ref": "VPCPublicSubnet2RouteTable6F1A15F1"
@@ -169,7 +166,10 @@
         "GatewayId": {
           "Ref": "VPCIGWB7E252D3"
         }
-      }
+      },
+      "DependsOn": [
+        "VPCVPCGW99B986DC"
+      ]
     },
     "VPCPublicSubnet2EIP4947BC00": {
       "Type": "AWS::EC2::EIP",
@@ -449,4 +449,4 @@
       }
     }
   }
-}
+}

packages/@aws-cdk/aws-autoscaling/test/integ.asg-w-classic-loadbalancer.expected.json

@@ -708,7 +708,10 @@
             "Ref": "VPCPublicSubnet3Subnet631C5E25"
           }
         ]
-      }
+      },
+      "DependsOn": [
+        "VPCIGWB7E252D3"
+      ]
     }
   }
 }

packages/@aws-cdk/aws-autoscaling/test/integ.asg-w-elbv2.expected.json

@@ -569,7 +569,10 @@
           }
         ],
         "Type": "application"
-      }
+      },
+      "DependsOn": [
+        "VPCIGWB7E252D3"
+      ]
     },
     "LBSecurityGroup8A41EA2B": {
       "Type": "AWS::EC2::SecurityGroup",

packages/@aws-cdk/aws-ec2/lib/vpc-ref.ts

@@ -119,6 +119,11 @@ export abstract class VpcNetworkRef extends Construct implements IDependable {
    */
   public readonly dependencyElements: IDependable[] = [];
 
+  /**
+   * Dependencies for internet connectivity
+   */
+  protected readonly internetDependencies = new Array<IDependable>();
+
   /**
    * Return the subnets appropriate for the placement strategy
    */
@@ -177,6 +182,19 @@ export abstract class VpcNetworkRef extends Construct implements IDependable {
   public isPublicSubnet(subnet: VpcSubnetRef) {
     return this.publicSubnets.indexOf(subnet) > -1;
   }
+
+  /**
+   * Take a dependency on internet connectivity having been added to this VPC
+   *
+   * Take a dependency on this if your constructs need an Internet Gateway
+   * added to the VPC before they can be constructed.
+   *
+   * This method is for construct authors; application builders should not
+   * need to call this.
+   */
+  public internetDependency(): IDependable {
+    return new DependencyList(this.internetDependencies);
+  }
 }
 
 /**
@@ -340,3 +358,15 @@ export interface VpcSubnetRefProps {
    */
   subnetId: string;
 }
+
+/**
+ * Allows using an array as a list of dependables.
+ */
+class DependencyList implements IDependable {
+  constructor(private readonly dependenclyElements: IDependable[]) {
+  }
+
+  public get dependencyElements(): IDependable[] {
+    return this.dependenclyElements;
+  }
+}

packages/@aws-cdk/aws-ec2/lib/vpc.ts

@@ -312,6 +312,7 @@ export class VpcNetwork extends VpcNetworkRef implements cdk.ITaggable {
       const igw = new cloudformation.InternetGatewayResource(this, 'IGW', {
         tags: new cdk.TagManager(this),
       });
+      this.internetDependencies.push(igw);
       const att = new cloudformation.VPCGatewayAttachmentResource(this, 'VPCGW', {
         internetGatewayId: igw.ref,
         vpcId: this.resource.ref

packages/@aws-cdk/aws-ecs/test/ec2/integ.lb-awsvpc-nw.expected.json

@@ -866,7 +866,10 @@
           }
         ],
         "Type": "application"
-      }
+      },
+      "DependsOn": [
+        "VpcIGWD7BA715C"
+      ]
     },
     "LBSecurityGroup8A41EA2B": {
       "Type": "AWS::EC2::SecurityGroup",

packages/@aws-cdk/aws-ecs/test/ec2/integ.lb-bridge-nw.expected.json

@@ -829,7 +829,10 @@
           }
         ],
         "Type": "application"
-      }
+      },
+      "DependsOn": [
+        "VpcIGWD7BA715C"
+      ]
     },
     "LBSecurityGroup8A41EA2B": {
       "Type": "AWS::EC2::SecurityGroup",

packages/@aws-cdk/aws-ecs/test/fargate/integ.asset-image.expected.json

@@ -888,7 +888,10 @@
           }
         ],
         "Type": "application"
-      }
+      },
+      "DependsOn": [
+        "VpcIGWD7BA715C"
+      ]
     },
     "FargateServiceLBSecurityGroup5F444C78": {
       "Type": "AWS::EC2::SecurityGroup",

packages/@aws-cdk/aws-ecs/test/fargate/integ.lb-awsvpc-nw.expected.json

@@ -67,9 +67,6 @@
     },
     "VpcPublicSubnet1DefaultRoute3DA9E72A": {
       "Type": "AWS::EC2::Route",
-      "DependsOn": [
-        "VpcVPCGWBF912B6E"
-      ],
       "Properties": {
         "RouteTableId": {
           "Ref": "VpcPublicSubnet1RouteTable6C95E38E"
@@ -78,7 +75,10 @@
         "GatewayId": {
           "Ref": "VpcIGWD7BA715C"
         }
-      }
+      },
+      "DependsOn": [
+        "VpcVPCGWBF912B6E"
+      ]
     },
     "VpcPublicSubnet1EIPD7E02669": {
       "Type": "AWS::EC2::EIP",
@@ -158,9 +158,6 @@
     },
     "VpcPublicSubnet2DefaultRoute97F91067": {
       "Type": "AWS::EC2::Route",
-      "DependsOn": [
-        "VpcVPCGWBF912B6E"
-      ],
       "Properties": {
         "RouteTableId": {
           "Ref": "VpcPublicSubnet2RouteTable94F7E489"
@@ -169,7 +166,10 @@
         "GatewayId": {
           "Ref": "VpcIGWD7BA715C"
         }
-      }
+      },
+      "DependsOn": [
+        "VpcVPCGWBF912B6E"
+      ]
     },
     "VpcPublicSubnet2EIP3C605A87": {
       "Type": "AWS::EC2::EIP",
@@ -581,7 +581,10 @@
           }
         ],
         "Type": "application"
-      }
+      },
+      "DependsOn": [
+        "VpcIGWD7BA715C"
+      ]
     },
     "LBSecurityGroup8A41EA2B": {
       "Type": "AWS::EC2::SecurityGroup",
@@ -669,4 +672,4 @@
       }
     }
   }
-}
+}

packages/@aws-cdk/aws-elasticloadbalancing/lib/load-balancer.ts

@@ -220,6 +220,9 @@ export class LoadBalancer extends cdk.Construct implements IConnectable, codedep
       scheme: props.internetFacing ? 'internet-facing' : 'internal',
       healthCheck: props.healthCheck && healthCheckToJSON(props.healthCheck),
     });
+    if (props.internetFacing) {
+      this.elb.addDependency(props.vpc.internetDependency());
+    }
 
     ifUndefined(props.listeners, []).forEach(b => this.addListener(b));
     ifUndefined(props.targets, []).forEach(t => this.addTarget(t));

packages/@aws-cdk/aws-elasticloadbalancing/test/integ.elb.expected.json

@@ -67,9 +67,6 @@
     },
     "VPCPublicSubnet1DefaultRoute91CEF279": {
       "Type": "AWS::EC2::Route",
-      "DependsOn": [
-        "VPCVPCGW99B986DC"
-      ],
       "Properties": {
         "RouteTableId": {
           "Ref": "VPCPublicSubnet1RouteTableFEE4B781"
@@ -78,7 +75,10 @@
         "GatewayId": {
           "Ref": "VPCIGWB7E252D3"
         }
-      }
+      },
+      "DependsOn": [
+        "VPCVPCGW99B986DC"
+      ]
     },
     "VPCPublicSubnet1EIP6AD938E8": {
       "Type": "AWS::EC2::EIP",
@@ -249,7 +249,10 @@
             "Ref": "VPCPublicSubnet1SubnetB4246D30"
           }
         ]
-      }
+      },
+      "DependsOn": [
+        "VPCIGWB7E252D3"
+      ]
     }
   }
 }

packages/@aws-cdk/aws-elasticloadbalancingv2/lib/shared/base-load-balancer.ts

@@ -110,6 +110,9 @@ export abstract class BaseLoadBalancer extends cdk.Construct implements route53.
       loadBalancerAttributes: new cdk.Token(() => renderAttributes(this.attributes)),
       ...additionalProps
     });
+    if (internetFacing) {
+      resource.addDependency(this.vpc.internetDependency());
+    }
 
     if (baseProps.deletionProtection) { this.setAttribute('deletion_protection.enabled', 'true'); }
 

packages/@aws-cdk/aws-elasticloadbalancingv2/test/alb/test.load-balancer.ts

@@ -1,4 +1,4 @@
-import { expect, haveResource } from '@aws-cdk/assert';
+import { expect, haveResource, ResourcePart } from '@aws-cdk/assert';
 import ec2 = require('@aws-cdk/aws-ec2');
 import s3 = require('@aws-cdk/aws-s3');
 import cdk = require('@aws-cdk/cdk');
@@ -31,6 +31,25 @@ export = {
     test.done();
   },
 
+  'internet facing load balancer has dependency on IGW'(test: Test) {
+    // GIVEN
+    const stack = new cdk.Stack();
+    const vpc = new ec2.VpcNetwork(stack, 'Stack');
+
+    // WHEN
+    new elbv2.ApplicationLoadBalancer(stack, 'LB', {
+      vpc,
+      internetFacing: true,
+    });
+
+    // THEN
+    expect(stack).to(haveResource('AWS::ElasticLoadBalancingV2::LoadBalancer', {
+      DependsOn: ['StackIGW2F0A1126']
+    }, ResourcePart.CompleteDefinition));
+
+    test.done();
+  },
+
   'Trivial construction: internal'(test: Test) {
     // GIVEN
     const stack = new cdk.Stack();