#59: Added --import commandline switch by adding an argument preparsi…

…ng mechanism

src/rkd/__init__.py

@@ -39,22 +39,25 @@ def prepend_development_paths():
         sys.path = [os.getcwd() + '/src'] + sys.path
 
     def main(self, argv: list):
-        if not argv[1:]:
+        if not CommandlineParsingHelper.has_any_task(argv) and not CommandlineParsingHelper.was_help_used(argv):
             self.print_banner_and_exit()
 
         # system wide IO instance with defaults, the :init task should override those settings
         io = SystemIO()
         io.silent = True
         io.set_log_level(os.getenv('RKD_SYS_LOG_LEVEL', 'info'))
 
+        # preparse arguments that are before tasks
+        preparsed_args = CommandlineParsingHelper.preparse_args(argv)
+
         # load context of components - all tasks, plugins etc.
         try:
-            self._ctx = ContextFactory(io).create_unified_context(
-                additional_imports=os.getenv('RKD_IMPORTS', '').split(':') if os.getenv('RKD_IMPORTS') else []
-            )
+            self._ctx = ContextFactory(io).create_unified_context(additional_imports=preparsed_args['imports'])
+
         except ParsingException as e:
             io.silent = False
-            io.error_msg('Cannot import tasks/module from RKD_IMPORTS environment variable. Details: {}'.format(str(e)))
+            io.error_msg('Cannot import tasks/module from RKD_IMPORTS environment variable or --import switch. '
+                         'Details: {}'.format(str(e)))
             sys.exit(1)
 
         except YamlParsingException as e:
@@ -94,6 +97,7 @@ def main():
 
     try:
         app.main(argv=sys.argv)
+
     except TaskNotFoundException as e:
         print(e)
         sys.exit(127)

src/rkd/argparsing.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+import os
 from typing import List
 from typing import Tuple
 from argparse import ArgumentParser
@@ -157,12 +158,12 @@ def parse(cls, task: TaskDeclarationInterface, args: list) -> Tuple[dict, dict]:
         argparse.add_argument('--become', '-rb', help='Execute task as given user (requires sudo)', default='')
 
         task.get_task_to_execute().configure_argparse(argparse)
-        cls.add_env_variables_to_argparse(argparse, task)
+        cls.add_env_variables_to_argparse_description(argparse, task)
 
         return vars(argparse.parse_args(args)), argparse.traced_arguments
 
     @classmethod
-    def add_env_variables_to_argparse(cls, argparse: ArgumentParser, task: TaskDeclarationInterface):
+    def add_env_variables_to_argparse_description(cls, argparse: ArgumentParser, task: TaskDeclarationInterface):
         if argparse.description is None:
             argparse.description = ""
 
@@ -180,3 +181,55 @@ def add_env_variables_to_argparse(cls, argparse: ArgumentParser, task: TaskDecla
 
         if not task.get_task_to_execute().get_declared_envs():
             argparse.description += ' -- No environment variables declared -- '
+
+    @staticmethod
+    def preparse_args(args: List[str]):
+        """
+        Parses commandline arguments which are not accessible on tasks level, but are accessible behind tasks
+        Those arguments should decide about RKD core behavior on very early stage
+
+        :param args:
+        :return:
+        """
+
+        limited_args = []
+
+        for arg in args:
+            if arg.startswith(':') or arg.startswith('@'):
+                break
+
+            limited_args.append(arg)
+
+        argparse = ArgumentParser(add_help=False)
+        argparse.add_argument('--import', '-ri')
+
+        parsed = vars(argparse.parse_known_args(args=limited_args)[0])
+
+        return {
+            'imports': list(filter(None,
+                                   os.getenv('RKD_IMPORT', parsed['import'] if parsed['import'] else '').split(':')
+                                   ))
+        }
+
+    @staticmethod
+    def has_any_task(argv: List[str]) -> bool:
+        """
+        Checks if arguments contains at least one task
+
+        :param argv:
+        :return:
+        """
+
+        for arg in argv:
+            if arg.startswith(':'):
+                return True
+
+        return False
+
+    @staticmethod
+    def was_help_used(argv: List[str]) -> bool:
+        for arg in argv:
+            if arg in ['-h', '--help']:
+                return True
+
+        return False

src/rkd/standardlib/__init__.py

@@ -40,14 +40,19 @@ def get_declared_envs(self) -> Dict[str, str]:
             'RKD_ALIAS_GROUPS': '',        # supported by core, here only for documentation in CLI
             'RKD_UI': 'true',
             'RKD_SYS_LOG_LEVEL': 'info',   # supported by core, here only for documentation in CLI
-            'RKD_IMPORTS': ''              # supported by core, here only for documentation in CLI
+            'RKD_IMPORT': ''               # supported by core, here only for documentation in CLI
         }
 
     def configure_argparse(self, parser: ArgumentParser):
         parser.add_argument('--no-ui', '-n', action='store_true',
                             help='Do not display RKD interface (similar to --silent, ' +
                                  'but does not inherit --silent into next tasks)')
 
+        parser.add_argument('--import', '-ri',
+                            help='Imports a task or list of tasks separated by ":". '
+                                 'Example: "rkt_utils.docker:rkt_ciutils.boatci:rkd_python". '
+                                 'Instead of switch there could be also environment variable "RKD_IMPORT" used')
+
     def execute(self, context: ExecutionContext) -> bool:
         """
         :init task is setting user-defined global defaults on runtime

test/test_argparsing.py

@@ -34,7 +34,7 @@ def test_add_env_variables_to_argparse(self):
         parser = ArgumentParser(':test')
         task = get_test_declaration()
 
-        CommandlineParsingHelper.add_env_variables_to_argparse(parser, task)
+        CommandlineParsingHelper.add_env_variables_to_argparse_description(parser, task)
         self.assertIn('ORG_NAME (default: International Workers Association)', parser.description)
 
     def test_add_env_variables_to_argparse__no_envs(self):
@@ -44,7 +44,7 @@ def test_add_env_variables_to_argparse__no_envs(self):
         # empty the values
         task.get_task_to_execute().get_declared_envs = lambda: {}
 
-        CommandlineParsingHelper.add_env_variables_to_argparse(parser, task)
+        CommandlineParsingHelper.add_env_variables_to_argparse_description(parser, task)
         self.assertNotIn('ORG_NAME (default: International Workers Association)', parser.description)
         self.assertIn('-- No environment variables declared --', parser.description)