scripts: domains: Support initialization only from YAML

By requiring a full-on YAML fragment, the Domains class can rely on
pykwalify to do the heavy lifting with validating types and structure.
Remove support for loading domains from a dictionary, so that we don't
ever have to replicate the same checks on the input, and we can instead
have a single entry point.

Signed-off-by: Grzegorz Swiderski <grzegorz.swiderski@nordicsemi.no>

scripts/pylib/build_helpers/domains.py

@@ -56,7 +56,15 @@ logger.addHandler(handler)
 
 class Domains:
 
-    def __init__(self, data):
+    def __init__(self, domains_yaml):
+        try:
+            data = yaml.safe_load(domains_yaml)
+            pykwalify.core.Core(source_data=data,
+                                schema_data=schema).validate()
+        except (yaml.YAMLError, pykwalify.errors.SchemaError):
+            logger.critical(f'malformed domains.yaml')
+            exit(1)
+
         self._build_dir = data['build_dir']
         self._domains = {
             d['name']: Domain(d['name'], d['build_dir'])
@@ -72,32 +80,22 @@ class Domains:
 
     @staticmethod
     def from_file(domains_file):
-        '''Load domains from domains.yaml.
-
-        Exception raised:
-           - ``FileNotFoundError`` if the domains file is not found.
+        '''Load domains from a domains.yaml file.
         '''
         try:
             with open(domains_file, 'r') as f:
-                domains = yaml.safe_load(f.read())
+                domains_yaml = f.read()
         except FileNotFoundError:
             logger.critical(f'domains.yaml file not found: {domains_file}')
             exit(1)
 
-        try:
-            pykwalify.core.Core(source_data=domains, schema_data=schema)\
-                .validate()
-        except pykwalify.errors.SchemaError:
-            logger.critical(f'ERROR: Malformed yaml in file: {domains_file}')
-            exit(1)
-
-        return Domains(domains)
+        return Domains(domains_yaml)
 
     @staticmethod
-    def from_data(domains_data):
-        '''Load domains from domains dictionary.
+    def from_yaml(domains_yaml):
+        '''Load domains from a string with YAML contents.
         '''
-        return Domains(domains_data)
+        return Domains(domains_yaml)
 
     def get_domains(self, names=None, default_flash_order=False):
         if names is None:

scripts/west_commands/build_helpers.py

@@ -151,9 +151,14 @@ def load_domains(path):
     domains_file = Path(path) / 'domains.yaml'
 
     if not domains_file.is_file():
-        return Domains.from_data({'default': 'app',
-                                  'build_dir': path,
-                                  'domains': [{'name': 'app', 'build_dir': path}],
-                                  'flash_order': ['app']})
+        return Domains.from_yaml(f'''\
+default: app
+build_dir: {path}
+domains:
+  - name: app
+    build_dir: {path}
+flash_order:
+  - app
+''')
 
     return Domains.from_file(domains_file)