Refactor 'id' schema for SLO resource

[b-deam]

Firstly let me caveat this PR with the fact that WRT to Go or TF providers:

So please review very carefully. I tried to be comprehensive in my own testing locally by trying to cause conflicting IDs, updating/destroying etc.

I tested this locally using this sample file:

terraform {
  required_providers {
    elasticstack = {
      source = "elastic/elasticstack"
    }
  }
}

provider "elasticstack" {
  elasticsearch {
    username  = "elastic"
    password  = "changeme"
    endpoints = ["https://localhost:9200"]
    insecure  = true
  }
  kibana {
    username  = "elastic"
    password  = "changeme"
    endpoints = ["https://localhost:5601"]
    insecure  = true
  }
}


resource "elasticstack_kibana_slo" "test_one" {
  name        = "My Test SLO 1"
  description = "My SLO description 1"
  // no slo_id set
  kql_custom_indicator {
    index           = "kibana_sample_data_logs"
    good            = "hour_of_day > 3"
    total           = "*"
    timestamp_field = "@timestamp"
  }

  time_window {
    duration = "7d"
    type     = "rolling"
  }

  budgeting_method = "timeslices"

  objective {
    target           = 0.95
    timeslice_target = 0.95
    timeslice_window = "5m"
  }

  settings {
    sync_delay = "5m"
    frequency  = "5m"
  }

  tags = ["test-1"]
}

resource "elasticstack_kibana_slo" "test_two" {
  name        = "My Test SLO 2"
  description = "My SLO description 2"
  slo_id          = "my-test-slo-2"
  kql_custom_indicator {
    index           = "kibana_sample_data_log"
    good            = "hour_of_day > 100"
    total           = "*"
    timestamp_field = "@timestamp"
  }

  time_window {
    duration = "7d"
    type     = "rolling"
  }

  budgeting_method = "timeslices"

  objective {
    target           = 0.95
    timeslice_target = 0.95
    timeslice_window = "5m"
  }

  settings {
    sync_delay = "5m"
    frequency  = "5m"
  }

  tags = ["test-2"]
}

resource "elasticstack_kibana_slo" "test_two_conflict" {
  name        = "My Test SLO 3"
  description = "My SLO description 3"
  // Conflicting ID results in 500 back from Kibana
  // Doesn't appear to be a way to ensure uniqueness across resources
  // https://github.com/hashicorp/terraform-plugin-sdk/issues/224
  slo_id          = "my-test-slo-2"
  kql_custom_indicator {
    index           = "kibana_sample_data_log"
    good            = "hour_of_day > 1"
    total           = "*"
    timestamp_field = "@timestamp"
  }

  time_window {
    duration = "7d"
    type     = "rolling"
  }

  budgeting_method = "timeslices"

  objective {
    target           = 0.95
    timeslice_target = 0.95
    timeslice_window = "5m"
  }

  settings {
    sync_delay = "5m"
    frequency  = "5m"
  }

  tags = ["test-2"]
}

Fixes #621

Relates (I think) to:

• Allow provider to define uniqueness of a resource hashicorp/terraform-plugin-sdk#224
• Global IDs for representing relationships between resource objects (object containment, name collision detection, etc) hashicorp/terraform#22094

[tobio]

LGTM. Can you add an entry to CHANGELOG.md for this one.

It might be worthwhile adding an acceptance test explicitly setting the ID?

[tobio]

LGTM