cmu: Add an option to disable Kubernetes support

It might seem counter-intuitive to disable Kubernetes support
in a toolkit meant for managing Kubernetes clusters, but just
in case you only want to use cmu to run Ansible playbooks
and look at logs this option allows for removing the slowdown
during startup spent while trying to connect to the API-server.

Signed-off-by: David Weinehall <[email protected]>

cmu

@@ -115,6 +115,9 @@ initial_container = None
 # Is cmu running in read only-mode?
 read_only_mode = False
 
+# Is Kubernetes support enabled
+kubernetes_support = True
+
 # Namespace
 selected_namespace = ""
 
@@ -129,7 +132,9 @@ def init_kubernetes_client() -> None:
 	"""
 
 	global kh # pylint: disable=global-statement
-	kh = KubernetesHelper(about.PROGRAM_SUITE_NAME, about.PROGRAM_SUITE_VERSION, None)
+
+	if kubernetes_support:
+		kh = KubernetesHelper(about.PROGRAM_SUITE_NAME, about.PROGRAM_SUITE_VERSION, None)
 
 override_tail_lines = None
 default_tail_lines = 4000
@@ -139,6 +144,9 @@ def gather_cluster_info() -> None:
 	Gather information about the cluster necessary for running playbooks
 	"""
 
+	if not kubernetes_support:
+		return
+
 	ansithemeprint([ANSIThemeString("[Gathering cluster information]\n", "phase")])
 
 	# Set global variables that need to be available when executing playbooks
@@ -4180,12 +4188,16 @@ def get_inventory_list(**kwargs: Dict) -> Tuple[List[Dict], int, Any, Callable,
 
 	control_plane_node, control_plane_name = get_control_plane()
 
-	node_vlist, status = kh.get_list_by_kind_namespace(("Node", ""), "")
-	for node in node_vlist:
-		roles = kh.get_node_roles(node)
-		if "control-plane" in roles:
-			continue
-		nodes.append(deep_get(node, DictPath("metadata#name")))
+	if kubernetes_support:
+		node_vlist, status = kh.get_list_by_kind_namespace(("Node", ""), "")
+		for node in node_vlist:
+			roles = kh.get_node_roles(node)
+			if "control-plane" in roles:
+				continue
+			nodes.append(deep_get(node, DictPath("metadata#name")))
+	else:
+		nodes = []
+		status = 200
 
 	if len(nodes) > 0:
 		ansible_add_hosts(ANSIBLE_INVENTORY, nodes, group = "nodes")
@@ -4375,6 +4387,9 @@ def get_node_info(vlist, extra_vars) -> List[Type]:
 
 # To make the failure case easier, return both the ref and the name of the control plane
 def get_control_plane() -> Tuple[Dict, str]:
+	if not kubernetes_support:
+		return None, ""
+
 	vlist, status = kh.get_list_by_kind_namespace(("Node", ""), "")
 	control_planes = []
 
@@ -11102,7 +11117,11 @@ def format_selection_list(uip: UIProps, refresh_apis = False):
 		# Repopulate the list of views, on the offhand chance that a view file has been added
 		populate_views(force_refresh = refresh_apis)
 		curses.doupdate()
-	available_api_families, _status, _modified = kh.get_available_kinds()
+
+	if kubernetes_support:
+		available_api_families, _status, _modified = kh.get_available_kinds()
+	else:
+		available_api_families = {}
 
 	items = []
 	order = []
@@ -11295,15 +11314,19 @@ listviewactions = {
 infoviews = {} # type: ignore
 
 # These functions are used to check whether an API is available
+def is_kubernetes_supported() -> bool:
+	return kubernetes_support
+
 def is_cluster_reachable() -> bool:
 	reachable = False
 
-	if kh is not None:
+	if kubernetes_support and kh is not None:
 		reachable = kh.is_cluster_reachable()
 	return reachable
 
 availability_checker_allowlist = {
-	"is_cluster_reachable": is_cluster_reachable
+	"is_cluster_reachable": is_cluster_reachable,
+	"is_kubernetes_supported": is_kubernetes_supported,
 }
 
 # action calls acceptable for direct use in view files
@@ -11523,7 +11546,11 @@ def map_key(view_file: str, shortcut: str, activatedfun, key: str, modifier: str
 def populate_views(force_refresh: bool = False) -> None:
 	global views # pylint: disable=global-statement
 
-	tmp_available_api_families, _status, _modified = kh.get_available_kinds(force_refresh = force_refresh)
+	if kubernetes_support:
+		tmp_available_api_families, _status, _modified = kh.get_available_kinds(force_refresh = force_refresh)
+	else:
+		tmp_available_api_families = {}
+
 	available_api_families = set()
 	for kind, kind_data in tmp_available_api_families.items():
 		if deep_get(kind_data, DictPath("available"), False) == True:
@@ -11560,17 +11587,14 @@ def populate_views(force_refresh: bool = False) -> None:
 			if not filename.endswith((".yaml", ".yml")):
 				continue
 
-			if len(available_api_families) > 0:
-				match_tmp = yaml_regex.match(filename)
-				tmp = match_tmp[1]
-				if "." in tmp:
-					kind, api_family = tmp.split(".", 1)
-				else:
-					kind = tmp
-					api_family = ""
-				if (kind, api_family) in available_api_families or kind.startswith("__"):
-					view_files.append(os.path.join(view_dir, filename))
+			match_tmp = yaml_regex.match(filename)
+			tmp = match_tmp[1]
+			if "." in tmp:
+				kind, api_family = tmp.split(".", 1)
 			else:
+				kind = tmp
+				api_family = ""
+			if (kind, api_family) in available_api_families or kind.startswith("__"):
 				view_files.append(os.path.join(view_dir, filename))
 
 	for view_file in view_files:
@@ -12037,7 +12061,9 @@ def populate_views(force_refresh: bool = False) -> None:
 			# Add the new view
 			infoviews[(kind, api_family)] = infoview_entry
 			has_infoview = True
-		kh_update_api_status((kind, api_family), listview = has_listview, infoview = has_infoview)
+
+		if kubernetes_support:
+			kh_update_api_status((kind, api_family), listview = has_listview, infoview = has_infoview)
 
 def setupui(stdscr: curses.window) -> None:
 	# Hide the cursor
@@ -12057,6 +12083,15 @@ def setupui(stdscr: curses.window) -> None:
 			viewfunc = deep_get(views, DictPath(f"{defaultview}#viewfunc"))
 			if viewfunc is None:
 				viewfunc = genericlistloop
+			check_availability = deep_get(views, DictPath(f"{defaultview}#check_availability"))
+			if check_availability is not None and not check_availability():
+				curses.endwin()
+				ansithemeprint([ANSIThemeString("Error", "error"),
+						ANSIThemeString(": The requested view “", "default"),
+						ANSIThemeString(defaultview, "argument"),
+						ANSIThemeString("“ is not available; ", "default"),
+						ANSIThemeString("the cluster may be offline or the API disabled.", "default")], stderr = True)
+				sys.exit(errno.ENOTSUP)
 			viewfunc(stdscr, defaultview)
 		else:
 			curses.endwin()
@@ -12295,6 +12330,7 @@ def open_view(options: List[Tuple[str, str]], args: List[str]) -> None:
 	global read_only_mode # pylint: disable=global-statement
 	global selected_namespace # pylint: disable=global-statement
 	global defaultview # pylint: disable=global-statement
+	global kubernetes_support # pylint: disable=global-statement
 
 	tmpdefaultview = deep_get(cmtlib.cmtconfig, DictPath("Global#defaultview"), "")
 
@@ -12303,8 +12339,11 @@ def open_view(options: List[Tuple[str, str]], args: List[str]) -> None:
 			selected_namespace = optarg
 		elif opt == "--read-only":
 			read_only_mode = True
+		elif opt == "--disable-kubernetes":
+			kubernetes_support = False
 
 	init_kubernetes_client()
+
 	# Customises the list views
 	ansithemeprint([ANSIThemeString("Populating list of supported views...\n", "default")])
 
@@ -12357,7 +12396,8 @@ def open_view(options: List[Tuple[str, str]], args: List[str]) -> None:
 
 	init_kubernetes_client()
 	ansithemeprint([ANSIThemeString("Checking available Kubernetes APIs\n", "default")])
-	_available_api_families, _status, _modified = kh.get_available_kinds()
+	if kubernetes_support:
+		_available_api_families, _status, _modified = kh.get_available_kinds()
 
 	# Customises the list views if necessary
 	if len(infoviews) == 0:
@@ -12586,6 +12626,15 @@ COMMANDLINE = {
 			"--read-only": {
 				"description": [ANSIThemeString("disable all commands that modify state", "description")],
 			},
+			"--disable-kubernetes": {
+				"description": [ANSIThemeString("disable Kubernetes support", "description")],
+				"extended_description": [
+					[ANSIThemeString("This option disables Kubernetes support; ", "description")],
+					[ANSIThemeString("this is typically only useful if you use", "description")],
+					[ANSIThemeString(about.UI_PROGRAM_NAME, "programname"),
+					 ANSIThemeString(" to manage an Ansible inventory", "description")],
+				],
+			},
 			"--namespace": {
 				"description": [ANSIThemeString("only show namespace ", "description"),
 						ANSIThemeString("NAMESPACE", "argument")],

tests/schemas/views.json

@@ -1133,7 +1133,8 @@
 				"check_availability": {
 					"description": "Function to use to check whether the API is available",
 					"enum": [
-						"is_cluster_reachable"
+						"is_cluster_reachable",
+						"is_kubernetes_supported"
 					]
 				},
 				"field_indexes": {

views/__Context.yaml

@@ -8,6 +8,7 @@ listview:
   listgetter_args:
     key: "server_address"
     retrigger_timeout: 300
+  check_availability: "is_kubernetes_supported"
   on_activation:
     call: null
   name: "Contexts"