Transform CF custom hook for IaC tool

[mvaude]

Challenge

With CF stack, Sauron is notified when the stack is run.

How can we handle in other IaC tool? (terraform and pulumi)

[tibor-szalai]

Not the most elegant solution but maybe we could try to utilise null_resorce? Is possible to notify Sauron via command line? Please let me know what you think.

First we need to test if are they running the terraform commands from windows or linux. I have found this online. The pathexpand function will return the full path and on Linux, this full path will always begin with / or root whereas on Windows this starts with a drive letter.

locals {
  test = pathexpand("~/${path.module}/main.tf")
  command_map = substr(local.test,0,1) == "/"? {
        command = "sleep 20",
        intrepreter = "bash"
      }:{
        command = "start-sleep 20", 
        intrepreter = "powershell"
      }
}

resource "null_resource" "localexec" {
  provisioner "local-exec" {
    command = local.command_map.command
    interpreter = [local.command_map.intrepreter]
  }
  triggers = {
      trigger = local.command_map.command
  }
}

[migueldelucasdoit]

Great idea @tibor-szalai we need to mimic the behavior of a Cloud Formation custom resource

It might be possible using curl or a helper script with cfn-response module.

[mvaude]

After some Sauron infra and code inspection, we discover that the message send to the topic should look like:

{
  RequestType: "Create",
  ResourceProperties : {
    AccountId : "",
    RoleArn: ""
}