Argument parsing: Add environment variables list to --help

src/rkd/argparsing.py

@@ -2,6 +2,7 @@
 
 from typing import List
 from argparse import ArgumentParser
+from argparse import RawTextHelpFormatter
 from .contract import TaskDeclarationInterface
 
 
@@ -66,15 +67,31 @@ def create_grouped_arguments(commandline: List[str]) -> List[TaskArguments]:
 
         return tasks
 
-    @staticmethod
-    def get_parsed_vars_for_task(task: TaskDeclarationInterface, args: list):
-        argparse = ArgumentParser(task.to_full_name())
+    @classmethod
+    def get_parsed_vars_for_task(cls, task: TaskDeclarationInterface, args: list):
+        argparse = ArgumentParser(task.to_full_name(), formatter_class=RawTextHelpFormatter)
+
         argparse.add_argument('--log-to-file', '-rf', help='Capture stdout and stderr to file')
         argparse.add_argument('--log-level', '-rl', help='Log level: debug,info,warning,error,fatal')
         argparse.add_argument('--keep-going', '-rk', help='Allow going to next task, even if this one fails',
                               action='store_true')
         argparse.add_argument('--silent', '-rs', help='Do not print logs, just task output', action='store_true')
 
         task.get_task_to_execute().configure_argparse(argparse)
+        cls.add_env_variables_to_argparse(argparse, task)
 
         return vars(argparse.parse_args(args))
+
+    @classmethod
+    def add_env_variables_to_argparse(cls, argparse: ArgumentParser, task: TaskDeclarationInterface):
+        if argparse.description is None:
+            argparse.description = ""
+
+        # print all environment variables possible to use
+        argparse.description += "\nEnvironment variables for task \"%s\":\n" % task.to_full_name()
+
+        for env_name, default_value in task.get_task_to_execute().get_declared_envs().items():
+            argparse.description += " - %s (default: %s)\n" % (str(env_name), str(default_value))
+
+        if not task.get_task_to_execute().get_declared_envs():
+            argparse.description += ' -- No environment variables declared -- '

src/rkd/test.py

@@ -1,3 +1,4 @@
+from typing import Dict
 from argparse import ArgumentParser
 from .syntax import TaskDeclaration
 from .contract import TaskInterface, ExecutionContext
@@ -9,17 +10,22 @@ def __init__(self):
         self._io = NullSystemIO()
 
     def get_name(self) -> str:
-        pass
+        return ':test'
 
     def get_group_name(self) -> str:
-        pass
+        return ':rkd'
 
     def execute(self, context: ExecutionContext) -> bool:
-        pass
+        return True
 
     def configure_argparse(self, parser: ArgumentParser):
         pass
 
+    def get_declared_envs(self) -> Dict[str, str]:
+        return {
+            'Union': 'International Workers Association'
+        }
+
 
 def get_test_declaration() -> TaskDeclaration:
     return TaskDeclaration(TestTask(), {}, [])

test/test_argparsing.py

@@ -1,7 +1,9 @@
 #!/usr/bin/env python3
 
 import unittest
+from argparse import ArgumentParser
 from rkd.argparsing import CommandlineParsingHelper
+from rkd.test import get_test_declaration
 
 
 class ArgParsingTest(unittest.TestCase):
@@ -34,3 +36,21 @@ def test_creates_grouped_arguments_into_tasks__tasks_only(self):
         ])
 
         self.assertEqual("[Task<:harbor:start ([])>, Task<:harbor:status ([])>, Task<:harbor:stop ([])>]", str(parsed))
+
+    def test_add_env_variables_to_argparse(self):
+        parser = ArgumentParser(':test')
+        task = get_test_declaration()
+
+        CommandlineParsingHelper.add_env_variables_to_argparse(parser, task)
+        self.assertIn('Union (default: International Workers Association)', parser.description)
+
+    def test_add_env_variables_to_argparse__no_envs(self):
+        parser = ArgumentParser(':test')
+        task = get_test_declaration()
+
+        # empty the values
+        task.get_task_to_execute().get_declared_envs = lambda: {}
+
+        CommandlineParsingHelper.add_env_variables_to_argparse(parser, task)
+        self.assertNotIn('Union (default: International Workers Association)', parser.description)
+        self.assertIn('-- No environment variables declared --', parser.description)

test/test_functional.py

@@ -127,3 +127,14 @@ def test_logging_tasks_into_separate_files(self):
                 # clean up
             os.unlink(first.name)
             os.unlink(second.name)
+
+    def test_env_variables_listed_in_help(self):
+        full_output, exit_code = self._run_and_capture_output(['--help'])
+        self.assertIn('- RKD_DEPTH (default: 0)', full_output)
+
+    def test_env_variables_not_listed_in_tasks_task(self):
+        """ :tasks does not define any environment variables """
+
+        full_output, exit_code = self._run_and_capture_output([':tasks', '--help'])
+        self.assertNotIn('- RKD_DEPTH (default: 0)', full_output)
+        self.assertIn('-- No environment variables declared --', full_output)