update website doc to depict the use of sets in members resource

[Uk1288]

Description

Related Issue: 761

Terraform creates an instance for each member of a given set, when for_each is used to configure a resource block.

If for_each is used with resources that do bulk management like the tfe_team_organization_members and tfe_team_members, it results in the creation of multiple instances managing the same set of resources. See the example config below:

locals {
  all_users = toset([
    "[email protected]",
    "[email protected]",
  ])
}

resource "tfe_team" "test" {
  name         = "my-team-name"
  organization = "my-org-name"
}

resource "tfe_organization_membership" "all_membership" {
  organization = "my-org-name"
  for_each     = local.all_users
  email        = each.key
}

resource "tfe_team_organization_members" "all-members" {
  team_id  = tfe_team.test.id
  for_each = local.all_users
  organization_membership_ids = [
    tfe_organization_membership.all_membership[each.key].id
  ]
}

The above config results in multiple instances of tfe_team_organization_members managing a set of memberships. Running an Apply will succeed. During the destroy phase, each instance of the tfe_team_organization_members resource attempts to delete the same organization members. The first delete request succeeds but the subsequent requests fail. If there are n number of local.all_users, there will be n DELETE API request made with the same membership id set (the current delete implementation attempts to delete all existing memberships).

What is needed here, is for Terraform to create just 1 instance of tfe_team_organization_members which will manage all the organization members in the set. The for expression will accomplish this, see the updated tfe_team_organization_members config below:

resource "tfe_team_organization_members" "all-members" {
  team_id = tfe_team.test.id
  organization_membership_ids = [for member in local.all_users : 
     tfe_organization_membership.all_membership[member].id]
}

After investigating this issue, the conclusion is that it is beneficial to add this use case example to the doc hence this PR.

Testing plan

1. Apply and compare the listed config above

External links

• API documentation - for-each meta argument
• API documentation - for expression

Output from acceptance tests

[laurenolivia]

👍 Really clear description! Smoke tested this and it works as expected.