Neutron port resource fails to validate empty string

[Steven Hardy]

If you do this, the stack validation doesn't reject the empty string, and the create fails in a non-obvious way:

heat_template_version: 2013-05-23
parameters:
  net:
    type: string
    default: ""
resources:
  port:
    type: OS::Neutron::Port
    properties:
      network_id: {get_param: net}

| stack_status | CREATE_FAILED |
| stack_status_reason | Resource CREATE failed: BadRequest: resources.port: |
| | Unrecognized attribute(s) 'network'

In the engine log there's a backtrace where we've tried to pass the wrong "network" key with an empty string to neutron, instead of validating the network_id is invalid, which is fairly confusing when the empty string has been passed in via a user parameter or via a parent stack etc.

[Ukesh (ukeshkumar)]

It seems, it is correct behaviour. If you pass an invalid network id/name also, the stack will fail.

If we want to validate an empty string, have to add constraints in the parameter.

[Steven Hardy (shardy)]

It's not correct behaviour, because we don't fail fast (an empty string can never be a valid neutron network name or uuid), and when we do fail it's with a non-obvious error not a clear "stack validation failed" error.

[Ukesh (ukeshkumar)]

I check in the latest devstack with the above heat template provided. I am getting the below error

ubuntu@ukesh-os:/opt/stack$ heat stack-create test1 -f test.yaml
ERROR: Property error: : resources.port.properties.network_id: : Multiple network matches found for name '', use an ID to be more specific.