ELB Autoregistration by Martin Raison

ELB Autoregistration - Register Deregister.scala

// retrieve instance id using AWS instance metadata and Play! WS API
val request = WS.url("http://169.254.169.254/latest/meta-data/instance-id")
val instanceId = Await.result(request.get(), 1 minute).body // careful when blocking
 
// set up AWS EC2 and ELB clients
val EC2Client = new AmazonEC2Client
val ELBClient = new AmazonElasticLoadBalancingClient
val region = Region.getRegion(Regions.<your_region>)
EC2Client.setRegion(region)
ELBClient.setRegion(region)
 
// retrieve instance's ELB tag
val request = new DescribeTagsRequest(Seq(
    new Filter("key",Seq("ELB")),
    new Filter("resource-id",Seq(instanceId))
))
val result = EC2Client.describeTags(request)
val ELBName = result.getTags.head.getValue // assuming tag is there
 
// register to ELB
def registerToLoadBalancer() = {
    val instance = new Instance(instanceId)
    val request = new RegisterInstancesWithLoadBalancerRequest(ELBName, Seq(instance))
    ELBClient.registerInstancesWithLoadBalancer(request)
}
 
// deregister from ELB
def deregisterFromLoadBalancer() = {
    val instance = new Instance(instanceId)
    val request = new DeregisterInstancesFromLoadBalancerRequest(ELBName, Seq(instance))
    ELBClient.deregisterInstancesFromLoadBalancer(request)
}