Add RDE metadata

[adambarreiro]

Description

This PR adds metadata support to the vcd_rde resource and data source by adding the metadata_entry attribute, which is a set.

The peculiar characteristic about this one is that this is the first OpenAPI metadata feature, so it differs a bit from the existing implementation (XML based). Main differences:

• There can be multiple metadata entries with same key, but different namespace.
• Types are reduced in comparison to XML (there's no date, for instance).
• Each entry has an ID that has to be respected by the Provider during Terraform operations (this is guaranteed by getOpenApiMetadataOperations).

Nuances

As metadata_entry is a set, doing any modification to an entry shows that all entries will be deleted and re-created during terraform plan, which is not true. The code is "smart" enough (getOpenApiMetadataOperations ) to perform the minimal changes, that is, respects the metadata that is not changed and doesn't touch them during terraform apply.

This nuance has been mentioned as a note in the docs. More info:

• https://discuss.hashicorp.com/t/typeset-resource-always-want-to-destroy-and-recreate-everything-in-set-when-one-item-has-a-diff/54895
• https://discuss.hashicorp.com/t/typeset-is-not-picking-up-correct-changes/23735/2

Sample snippet

provider "vcd" {
# ...  
}


data "vcd_rde_type" "rde_type" {
  vendor  = "vmware"
  nss     = "tkgcluster"
  version = "1.0.0"
}
resource "vcd_rde" "test-rde" {
  org          = "System"
  rde_type_id  = data.vcd_rde_type.rde_type.id
  name         = "TestAccVcdRdeMetadata"
  input_entity = "{\"foo\":\"bar\"}" # We are just testing metadata so we don't care about entity state
  resolve      = true

  metadata_entry {
    key    = "stringKey1"
    value  = "stringValue1"
    type   = "StringEntry"
    domain = "TENANT"

    readonly   = false
    persistent = false
  }
  metadata_entry {
    key    = "numberKey1"
    value  = "1"
    type   = "NumberEntry"
    domain = "TENANT"

    readonly   = false
    persistent = false
  }
  metadata_entry {
    key    = "boolKey1"
    value  = "false"
    type   = "BoolEntry"
    domain = "TENANT"

    readonly   = false
    persistent = false
  }
  metadata_entry {
    key    = "readOnly1"
    value  = "readOnly1"
    type   = "StringEntry"
    domain = "TENANT"

    readonly   = true
    persistent = false
  }
  metadata_entry {
    key        = "namespace"
    value      = "namespace1"
    type       = "StringEntry"
    domain     = "TENANT"
    namespace  = "namespace1"
    readonly   = false
    persistent = false
  }
  metadata_entry {
    key        = "namespace"
    value      = "namespace2"
    type       = "StringEntry"
    domain     = "TENANT"
    namespace  = "namespace2"
    readonly   = false
    persistent = false
  }
  metadata_entry {
    key    = "provider1"
    value  = "provider1"
    type   = "StringEntry"
    domain = "PROVIDER"

    readonly   = false
    persistent = false
  }
  metadata_entry {
    key    = "persistent1"
    value  = "persistent1"
    type   = "StringEntry"
    domain = "TENANT"

    readonly   = false
    persistent = true
  }
}

Remember that RDEs don't have any UI, so these are the endpoints to perform checks in the backend:

# Get RDEs
https://{{vcd_host}}/cloudapi/1.0.0/entities/types/vmware/tkgcluster/1.0.0/

# Get specific RDE with ID metadata (change {{rde_id}} with the RDE urn from previous call, or get it from Terraform state/output)
https://{{vcd_host}}/cloudapi/1.0.0/entities/{{rde_id}}/metadata

To check namespace+key uniqueness, you can add blocks like

metadata_entry {
    key        = "namespace" # Repeat the same key
    value      = "namespace3" # Change the value (otherwise TypeSet considers a duplicate entry and does nothing)
    type       = "StringEntry"
    domain     = "TENANT"
    namespace  = "namespace2" # Repeat the same namespace
    readonly   = false
    persistent = false
}

[Didainius]

I see it is in progress yet, but one thing that caught my eye - I left one comment, but this is throughout this PR - we shouldn't test if VCD < 10.4.0 as 3.11 will not support it all anyway. The error user would get error straight from SDK as we require API to be >= 37.0

[Didainius]

Some more comments from me. I am testing it.