feat: extract yaml loading to a function and add one to expand any su…

…b `config_file` + error handling

cuesubmit/cuesubmit/Config.py

@@ -35,19 +35,55 @@
 
 def getConfigValues():
     """Reads the config file from disk and returns the values it defines."""
-    configData = {}
     configFile = os.environ.get(CONFIG_FILE_ENV_VAR)
     if not configFile:
         configFile = os.path.join(opencue.config.config_base_directory(), 'cuesubmit.yaml')
-    if os.path.exists(configFile):
-        with open(configFile, 'r') as data:
-            try:
-                configData = yaml.load(data, Loader=yaml.SafeLoader)
-            except yaml.YAMLError:
-                raise CuesubmitConfigError("Could not load yaml file: {}. Please check its "
-                                           "formatting".format(configFile))
+    configData = _loadYamlFile(yaml_file=configFile)
+    if 'RENDER_CMDS' in configData:
+        configData['RENDER_CMDS'] = _expandRenderConfigValues(configData['RENDER_CMDS'])
     return configData
 
+def _loadYamlFile(yaml_file):
+    """ Load config yaml as dict
+    :param yaml_file: path to a config.yaml file (path can be an env var)
+    :type yaml_file: str
+    :returns: yaml content
+    :rtype: dict
+    """
+    _yaml_file = os.path.expandvars(yaml_file)
+    if not os.path.exists(_yaml_file):
+        raise FileExistsError(f'{_yaml_file=} not found')
+    config_data = {}
+    with open(_yaml_file, 'r') as data:
+        try:
+            config_data = yaml.load(data, Loader=yaml.SafeLoader)
+        except yaml.YAMLError:
+            raise CuesubmitConfigError("Could not load yaml file: {}. Please check its "
+                                       "formatting".format(_yaml_file))
+    return config_data
+
+def _expandRenderConfigValues(RENDER_CMDS):
+    """ Looks through each render command and loads their 'config_file' if any
+    If 'config_file' is set but does not exist, replace its content with error for proper feedback
+
+    :param RENDER_CMDS: all render commands from the cuesubmit_config.yaml file
+    :type RENDER_CMDS: dict
+    :returns: Updated RENDER_CMDS
+    :rtype: dict
+    """
+    for job_type, _options in RENDER_CMDS.items():
+        _sub_config_file = _options.get('config_file')
+        if not _sub_config_file:
+            continue
+        try:
+            RENDER_CMDS[job_type] = _loadYamlFile(yaml_file=_sub_config_file)
+        except FileExistsError as error:
+            RENDER_CMDS[job_type] = {
+                'command': 'error',
+                'options': {
+                    '{ERROR}': error}
+            }
+    return RENDER_CMDS
 
 class CuesubmitConfigError(Exception):
     """Thrown when an error occurs reading the config file."""