Lambda Vpc placement

[IndikaUdagedara]

How does the VpcPlacement property of Function() map to VpcConfig in Lambda cloudformation resource?

VpcConfig accepts multiple subnets but VpcPlacement accepts only a single subnet (in SubnetName). May be I've got it wrong. Would be clearer if there's a cdk example of a Lambda placed in an Vpc. I think a fairly common scenario is placing a Lambda in an existing Vpc where the Vpc may not have been cloudformed (so the cdk cloudformation import will not work) . An example of that would be great.

[rix0rrr]

A subnet name selects all subnets created with that name in the subnetConfiguration set when creating the VPC. This setting is useful if you have multiple subnets of the same type, otherwise it's probably preferable to use subnetType to select the type you want (Public or Private).

Placing things in VPCs that weren't created using the CDK is not currently supported, although you can achieve the behavior by passing in matching parameters in the import properties: https://github.com/awslabs/aws-cdk/blob/master/packages/%40aws-cdk/aws-ec2/lib/vpc-ref.ts#L247

For example, if you have a public and private subnet and you want to place in the private subnet:

const vpc = ec2.VpcNetworkRef.import(this, 'VPC', {
  vpcId: 'vpc-12345',
  availabilityZones: ['us-east-1a', 'us-east-1b']
  publicSubnetIds: ['subnet-4381', 'subnet-123'],
  privateSubnetIds: ['subnet-1425', 'subnet-86845'],
});

new lambda.Function(this, 'Lambda', {
  vpc: vpc,
  vpcPlacement: { subnetType: ec2.subnetType.Private }
});

Private is the default, btw, so you don't need to specify that.