Resolve the default security group UUID dynamically instead of hardcoding it

The "default" security group VK Cloud auto-creates in every project has
a UUID unique to that project, but main.tf hardcoded one project's UUID
across all 4 instance resources (router, priv_srv_01/02/03) - not
portable to another project. Replaced with data.vkcs_networking_secgroup
(matched by name = "default", verified against the real provider schema
via terraform providers schema -json on the local provider mirror) behind
local.default_security_group_id. The new default_security_group_id
variable is a last-resort manual override via coalesce() for projects
where the lookup doesn't fit (non-standard name/SDN) - not the normal path.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hXR2ftXZZhJ4Y3XuSoR8r

terraform/main.tf

@@ -12,6 +12,22 @@ data "vkcs_networking_network" "extnet" {
   sdn  = "sprut"
 }
 
+# Every VK Cloud project auto-creates a "default" security group with a
+# UUID unique to that project - resolve it dynamically instead of
+# hardcoding one project's UUID. var.default_security_group_id is a
+# last-resort manual override (e.g. non-standard name/SDN in a project).
+data "vkcs_networking_secgroup" "default" {
+  name = "default"
+  sdn  = "sprut"
+}
+
+locals {
+  default_security_group_id = coalesce(
+    var.default_security_group_id,
+    data.vkcs_networking_secgroup.default.id
+  )
+}
+
 # LAN Network
 resource "vkcs_networking_network" "lan_net" {
   name           = "router-lan-net"
@@ -164,7 +180,7 @@ resource "vkcs_compute_instance" "router" {
 
   security_group_ids = [
     vkcs_networking_secgroup.router_sg.id,
-    "d479b4d7-55b3-4ff1-bf8d-24d826a38f11"
+    local.default_security_group_id
   ]
 
   config_drive = true
@@ -213,7 +229,7 @@ resource "vkcs_compute_instance" "priv_srv_01" {
 
   security_group_ids = [
     vkcs_networking_secgroup.private_sg.id,
-    "d479b4d7-55b3-4ff1-bf8d-24d826a38f11"
+    local.default_security_group_id
   ]
 
   network {
@@ -241,7 +257,7 @@ resource "vkcs_compute_instance" "priv_srv_02" {
 
   security_group_ids = [
     vkcs_networking_secgroup.private_sg.id,
-    "d479b4d7-55b3-4ff1-bf8d-24d826a38f11"
+    local.default_security_group_id
   ]
 
   network {
@@ -268,7 +284,7 @@ resource "vkcs_compute_instance" "priv_srv_03" {
 
   security_group_ids = [
     vkcs_networking_secgroup.private_sg.id,
-    "d479b4d7-55b3-4ff1-bf8d-24d826a38f11"
+    local.default_security_group_id
   ]
 
   network {

terraform/tests/test_terraform_delivery.py

@@ -75,6 +75,21 @@ def find_variable(doc, name):
     return None
 
 
+def find_local(doc, name):
+    """main.tf has more than one `locals { ... }` block - search all of them."""
+    for block in doc.get("locals", []):
+        if name in block:
+            return block[name]
+    return None
+
+
+def find_data_sources(doc, dtype):
+    """Yield (name, attrs) for every data source of a given type in a parsed doc."""
+    for block in doc.get("data", []):
+        if dtype in block:
+            yield from block[dtype].items()
+
+
 # ---------------------------------------------------------------------------
 # Delivery layout
 # ---------------------------------------------------------------------------
@@ -251,6 +266,21 @@ def test_router_count_validation_is_enforced(count, should_pass):
     assert ok == should_pass, f"unexpected result for router_count={count}:\n{output}"
 
 
+@pytest.mark.parametrize(
+    "override,should_pass",
+    [
+        (None, True),  # default null - no override, dynamic lookup is used
+        ("11111111-1111-1111-1111-111111111111", True),  # explicit override accepted
+    ],
+)
+def test_default_security_group_id_override_accepted(override, should_pass):
+    overrides = {}
+    if override is not None:
+        overrides["TF_VAR_default_security_group_id"] = override
+    ok, output = _plan_variables_only(overrides)
+    assert ok == should_pass, f"unexpected result for default_security_group_id={override!r}:\n{output}"
+
+
 # ---------------------------------------------------------------------------
 # HCL parses cleanly
 # ---------------------------------------------------------------------------
@@ -343,8 +373,8 @@ def test_no_legacy_hardcoded_router_resources():
 
 def test_private_roles_local_driven_by_variable():
     main = load_tf("main.tf")
-    locals_block = main["locals"][0]
-    assert locals_block["private_roles"] == [
+    private_roles = find_local(main, "private_roles")
+    assert private_roles == [
         '${[for idx in range(length(var.private_network_cidrs)) : "priv${idx + 1}"]}'
     ], "locals.private_roles must be generated from length(var.private_network_cidrs)"
 
@@ -359,6 +389,54 @@ def test_router_network_blocks_scale_with_private_roles():
     )
 
 
+# ---------------------------------------------------------------------------
+# main.tf: the "default" security group UUID is resolved dynamically, not
+# hardcoded (it's unique per VK Cloud project)
+# ---------------------------------------------------------------------------
+
+
+def test_default_security_group_data_source_exists():
+    main = load_tf("main.tf")
+    secgroups = dict(find_data_sources(main, "vkcs_networking_secgroup"))
+    assert "default" in secgroups, "expected data.vkcs_networking_secgroup.default"
+    assert secgroups["default"]["name"] == ["default"]
+
+
+def test_default_security_group_id_local_prefers_override_then_lookup():
+    main = load_tf("main.tf")
+    value = find_local(main, "default_security_group_id")
+    assert value == [
+        "${coalesce(var.default_security_group_id,"
+        "data.vkcs_networking_secgroup.default.id)}"
+    ], (
+        "locals.default_security_group_id must fall back to the dynamic "
+        "lookup unless var.default_security_group_id is explicitly overridden"
+    )
+
+
+def test_no_hardcoded_security_group_uuid_in_main():
+    text = (TERRAFORM_DIR / "main.tf").read_text()
+    uuid_pattern = re.compile(
+        r"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", re.I
+    )
+    assert not uuid_pattern.search(text), (
+        "main.tf must not contain a literal UUID (e.g. a hardcoded security "
+        "group ID) - it's unique per project and must be resolved dynamically "
+        "via data.vkcs_networking_secgroup or overridden via "
+        "var.default_security_group_id"
+    )
+
+
+def test_all_instances_use_default_security_group_local():
+    main = load_tf("main.tf")
+    for name, attrs in find_resources(main, "vkcs_compute_instance"):
+        sg_ids = attrs["security_group_ids"][0]
+        assert "${local.default_security_group_id}" in sg_ids, (
+            f"vkcs_compute_instance.{name} does not reference "
+            f"local.default_security_group_id in security_group_ids"
+        )
+
+
 # ---------------------------------------------------------------------------
 # terraform.tfvars example CIDRs: sanity-check the values actually shipped
 # (no auto-carving anymore - these come straight from the admin/example)

terraform/variables.tf

@@ -61,3 +61,9 @@ variable "private_network_cidrs" {
     error_message = "private_network_cidrs entries must be unique."
   }
 }
+
+variable "default_security_group_id" {
+  description = "Explicit override for the project's 'default' security group UUID. Last resort only - by default it's resolved dynamically via data.vkcs_networking_secgroup (see main.tf), since this UUID is unique per project and must not be hardcoded."
+  type        = string
+  default     = null
+}