Access a Vpc's Internet Gateway

Add an accessor to the Internet Gateway that was created by the Vpc construct.

Use Case

Trying to add a PublicSubnet to an existing Vpc (with existing public subnets), there is no way to create a route to the Vpc’s existing Internet Gateway, because the reference is not exposed anywhere (that I could find), so the PublicSubnet is not effectively public.

Proposed Solution

• Either add an accessor to a VPC’s internet gateway, if any
• Or have the PublicSubnet constructor automagically create the route from the VPC it’s a part of.

(Or, ideally, both)

Other

I’d take a workaround within CDK, that allows this without creating (and paying for) a second IGW…

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change

---

This is a 🚀 Feature Request

[jeanblanchard]

Update - I found my workaround, using an escape hatch to get the “IGW” child resource in the Vpc construct:

    const igw = vpc.node.findChild('IGW') as CfnInternetGateway;
    new CfnRoute(this, 'IGW', {
      routeTableId: subnet.routeTable.routeTableId,
      destinationCidrBlock: '0.0.0.0/0',
      gatewayId: igw.ref,
    });

[shearn89]

Having a stab at this, hope to have a PR out soon.