test(inventory/instnces): add tests for 'perInstance' arguments

lib/distributed-service/tests/per_instance_args.nix

@@ -0,0 +1,160 @@
+{ lib, callInventoryAdapter }:
+let
+  # Authored module
+  # A minimal module looks like this
+  # It isn't exactly doing anything but it's a valid module that produces an output
+  modules."A" = {
+    _class = "clan.service";
+    manifest = {
+      name = "network";
+    };
+    # Define two roles with unmergeable interfaces
+    # Both define some 'timeout' but with completely different types.
+    roles.peer.interface =
+      { lib, ... }:
+      {
+        options.timeout = lib.mkOption {
+          type = lib.types.str;
+        };
+      };
+
+    roles.peer.perInstance =
+      {
+        instanceName,
+        settings,
+        machine,
+        ...
+      }:
+      let
+        settings1 = settings {
+          # Sometimes we want to create a default settings set depending on the machine config.
+          # Note: Other machines cannot depend on this settings. We must assign a new name to the settings.
+          # And thus the new value is not accessible by other machines.
+          timeout = lib.mkOverride 10 "config.blah";
+        };
+      in
+      {
+        nixosModule = {
+          inherit instanceName settings machine;
+
+          # We are double vendoring the settings
+          # To test that we can do it indefinitely
+          vendoredSettings = settings1 {
+            # Sometimes we want to create a default settings set depending on the machine config.
+            # Note: Other machines cannot depend on this settings. We must assign a new name to the settings.
+            # And thus the new value is not accessible by other machines.
+            timeout = lib.mkOverride 5 "config.thing";
+          };
+        };
+      };
+  };
+  machines = {
+    jon = { };
+    sara = { };
+  };
+  res = callInventoryAdapter {
+    inherit modules machines;
+    instances."instance_foo" = {
+      module = {
+        name = "A";
+      };
+      roles.peer.machines.jon = {
+        settings.timeout = lib.mkForce "foo-peer-jon";
+      };
+      roles.peer = {
+        settings.timeout = "foo-peer";
+      };
+    };
+    instances."instance_bar" = {
+      module = {
+        name = "A";
+      };
+      roles.peer.machines.jon = {
+        settings.timeout = "bar-peer-jon";
+      };
+    };
+    # import the module "B" (undefined)
+    # All machines have this instance
+    instances."instance_zaza" = {
+      module = {
+        name = "B";
+      };
+      roles.peer.tags.all = { };
+    };
+  };
+
+  filterInternals = lib.filterAttrs (n: _v: !lib.hasPrefix "_" n);
+
+  # Replace internal attributes ('_' prefix)
+  # So we catch their presence but don't check the value
+  mapInternalsRecursive = lib.mapAttrsRecursive (
+    path: v:
+    let
+      name = lib.last path;
+    in
+    if !lib.hasPrefix "_" name then v else name
+  );
+in
+{
+  # settings should evaluate
+  test_per_instance_arguments = {
+    expr = {
+      instanceName =
+        res.evals.self-A.config.result.allRoles.peer.allInstances."instance_foo".allMachines.jon.nixosModule.instanceName;
+
+      # settings are specific.
+      # Below we access:
+      # instance = instance_foo
+      # roles = peer
+      # machines = jon
+      settings = filterInternals res.evals.self-A.config.result.allRoles.peer.allInstances.instance_foo.allMachines.jon.nixosModule.settings;
+      machine = mapInternalsRecursive res.evals.self-A.config.result.allRoles.peer.allInstances.instance_foo.allMachines.jon.nixosModule.machine;
+
+      # hasRoleSettings =
+      #   res.evals.self-A.config.result.allMachines.jon.nixosModule.instance_foo.roles.peer ? settings;
+
+      # # settings are specific.
+      # # Below we access:
+      # # instance = instance_foo
+      # # roles = peer
+      # # machines = *
+      # specificRoleSettings = filterInternals res.evals.self-A.config.result.allMachines.jon.nixosModule.instance_foo.roles.peer.settings;
+    };
+    expected = {
+      instanceName = "instance_foo";
+      settings = {
+        timeout = "foo-peer-jon";
+      };
+      machine = {
+        name = "jon";
+        roles = {
+          peer = {
+            machines = {
+              jon = {
+                settings = {
+                  __functor = "__functor";
+                  timeout = "foo-peer-jon";
+                };
+              };
+            };
+            settings = {
+              __functor = "__functor";
+              timeout = "foo-peer";
+            };
+          };
+        };
+      };
+    };
+  };
+
+  test_per_instance_settings_vendoring = {
+    expr =
+      mapInternalsRecursive
+        res.evals.self-A.config.result.allRoles.peer.allInstances."instance_foo".allMachines.jon.nixosModule.vendoredSettings;
+    expected = {
+      # Returns another override
+      __functor = "__functor";
+      timeout = "config.thing";
+    };
+  };
+}