fix: use node affinity objects instead of their keys when mapping

[vladklokun]

Previously, when a user specified node affinities, for every provided node affinity we would try to map every key to an "affinity" block. This produced invalid Terraform resources, because the values of the "key", "name" and "operator" keys on their own are not enough to create a valid "affinity" block.

This commit uses entire affinity objects and maps them to appropriate Terraform representations, fixing the problem.

UPD:

Steps to Reproduce

1. Set up the example manifest from the Cast AI GKE Cluster repo:

git clone [email protected]/castai/terraform-provider-castai.git
cd terraform-provider-castai/examples/gke/gke_cluster_autoscaler_policies
# Follow README.md#Usage to set up the example

2. Apply the following patch:

diff --git a/examples/gke/gke_cluster_autoscaler_policies/castai.tf b/examples/gke/gke_cluster_autoscaler_policies/castai.tf
index 268712d..ed895e8 100644
--- a/examples/gke/gke_cluster_autoscaler_policies/castai.tf
+++ b/examples/gke/gke_cluster_autoscaler_policies/castai.tf
@@ -102,6 +102,24 @@ module "castai-gke-cluster" {
       ]
 
       constraints = {
+        dedicated_node_affinity = {
+          name    = "test_affinity_foo"
+          az_name = "us-central1-c"
+          instance_types = ["e2-standard-2"]
+          affinity = [
+            {
+              key      = "gke.io/gcp-nodepool"
+              operator = "In"
+              values = ["foo"]
+            },
+            {
+              key      = "gke.io/gcp-nodepool-02"
+              operator = "In"
+              values = ["bar"]
+            }
+          ]
+        }
+
         fallback_restore_rate_seconds = 1800
         spot                          = true
         use_spot_fallbacks            = true

3. Plan:

tf plan -var-file tf.vars

4. Observe the output.

Expected output

A plan to apply with dedicated node affinity included:

Terraform will perform the following actions:

# Note: Snipped for brevity

Plan: 31 to add, 0 to change, 0 to destroy.

Actual output

The following error at the end of the plan:

Terraform planned the following actions, but then encountered a problem:

# Note: Snipped for brevity

Plan: 30 to add, 0 to change, 0 to destroy.

Error: Missing required argument

  with module.castai-gke-cluster.castai_node_template.this["spot_tmpl"],
  on .terraform/modules/castai-gke-cluster/main.tf line 37, in resource "castai_node_template" "this":
  37: resource "castai_node_template" "this" {

The argument "constraints.0.dedicated_node_affinity.0.affinity.0.operator" is
required, but no definition was found.

Error: Missing required argument

  with module.castai-gke-cluster.castai_node_template.this["spot_tmpl"],
  on .terraform/modules/castai-gke-cluster/main.tf line 37, in resource "castai_node_template" "this":
  37: resource "castai_node_template" "this" {

The argument "constraints.0.dedicated_node_affinity.0.affinity.1.operator" is
required, but no definition was found.