Import compound resources (experimental)

[dataclouder]

This PR explores the experimental Terraform import capabilities to use with some resources that have components not handled by Terraform.

Specifically, we try to facilitate the usage of

• shared catalogs (the vApp templates and media items are available to the receiving user, but they are not in Terraform state)
• cloned vApps, created by either a vApp template or another vApp, where the VMs are created without Terraform intervention.

In practical terms, this PR does the following:

• Adds the ability of creating a file containing import blocks using vcd_resource_list (property import_file_name);
• Changes the internals of vcd_resource_list to use genericResourceList for all resources. Therefore, we can create files with import blocks for all resources;
• Adds several resources to the list supported by vcd_resource_list
  • vcd_provider_vdc
  • vcd_org_ldap
  • vcd_org_saml
  • vcd_vdc_group
  • vcd_catalog_access_control
  • vcd_vapp_access_control
  • vcd_org_vdc_access_control
  • vcd_subscribed_catalog
  • vcd_cloned_vapp
  • vcd_edgegateway_settings
• Adds a guide on how to import resources using this experimental feature.
• Adds examples code for vApp/VMs import
• Adds examples code for catalog and contents import

Example:

Using this setup:

data "vcd_resource_list" "vms_from_vapp" {
  resource_type    = "vcd_vapp_vm"
  name             = "vms_from_vapp"
  parent           = vcd_cloned_vapp.vapp_from_vapp.name
  list_mode        = "import"
  import_file_name = "vms_from_vapp.tf"
}

data "vcd_resource_list" "vms_from_template" {
  resource_type    = "vcd_vapp_vm"
  name             = "vms_from_template"
  parent           = vcd_cloned_vapp.vapp_from_template.name
  list_mode        = "import"
  import_file_name = "vms_from_template.tf"
}

We obtain these files:

$ cat vms_from_template.tf vms_from_vapp.tf

# Generated by vcd_resource_list - 2023-08-06T16:30:10+02:00
# import data for vcd_vapp_vm datacloud.nsxt-vdc-datacloud.ClonedVAppFromTemplate.thirdVM
import {
  to = vcd_vapp_vm.thirdVM-a2aed82f4120
  id = "datacloud.nsxt-vdc-datacloud.ClonedVAppFromTemplate.thirdVM"
}

# import data for vcd_vapp_vm datacloud.nsxt-vdc-datacloud.ClonedVAppFromTemplate.firstVM
import {
  to = vcd_vapp_vm.firstVM-05781b374e0f
  id = "datacloud.nsxt-vdc-datacloud.ClonedVAppFromTemplate.firstVM"
}

# import data for vcd_vapp_vm datacloud.nsxt-vdc-datacloud.ClonedVAppFromTemplate.secondVM
import {
  to = vcd_vapp_vm.secondVM-297d88653cb3
  id = "datacloud.nsxt-vdc-datacloud.ClonedVAppFromTemplate.secondVM"
}

# Generated by vcd_resource_list - 2023-08-06T16:30:16+02:00
# import data for vcd_vapp_vm datacloud.nsxt-vdc-datacloud.AccClonedVAppFromVapp.thirdVM
import {
  to = vcd_vapp_vm.thirdVM-83f3fa702d07
  id = "datacloud.nsxt-vdc-datacloud.AccClonedVAppFromVapp.thirdVM"
}

# import data for vcd_vapp_vm datacloud.nsxt-vdc-datacloud.AccClonedVAppFromVapp.secondVM
import {
  to = vcd_vapp_vm.secondVM-038396a0070c
  id = "datacloud.nsxt-vdc-datacloud.AccClonedVAppFromVapp.secondVM"
}

# import data for vcd_vapp_vm datacloud.nsxt-vdc-datacloud.AccClonedVAppFromVapp.firstVM
import {
  to = vcd_vapp_vm.firstVM-0662aa45c523
  id = "datacloud.nsxt-vdc-datacloud.AccClonedVAppFromVapp.firstVM"
}

With this setup, we can run the command

terraform plan -generate-config-out=generated_vms.tf

and the next terraform apply will import the new resources in state.

[adezxc]

Closes #1012

[adezxc]

Looks good to me, again, very awesome implementation!

[lvirbalas]

Very powerful addition. Great to see that we don't need much changes in code to support the new experimental import from Terraform.

I'm adding some in-line comments. Main ask is to add more references in code and docs for the "new experimental Terraform import", because when you're reading without context it's easy to miss that point.

Thanks!

[lvirbalas]

Thanks for all the additions!

[adambarreiro]

Very nice feature, the examples worked like a charm and it's a super-powerful tool.