src/python/jw/pkg/lib/App.py

@@ -4,15 +4,18 @@ import asyncio
 import cProfile
 import os
 import sys
+import warnings
 
 from argparse import ArgumentDefaultsHelpFormatter, ArgumentParser, Namespace
-from typing import TYPE_CHECKING, Any, cast, override
+from typing import TYPE_CHECKING, Any, NamedTuple, cast, override
 
 from .AsyncRunner import AsyncRunner
+from .Cmd import AbstractCmd
 from .log import (
     DEBUG,
     ERR,
     NOTICE,
+    WARNING,
     LogFlag,
     log,
     log_m,
@@ -31,25 +34,47 @@ if TYPE_CHECKING:
     from typing import TypeVar
     T = TypeVar('T')
 
+def _get_current_event_loop() -> asyncio.AbstractEventLoop | None:
+    """Return the current event loop of this thread, or None if there is
+    none, without creating one implicitly or emitting a deprecation
+    warning."""
+    with warnings.catch_warnings():
+        warnings.simplefilter('error', DeprecationWarning)
+        try:
+            return asyncio.get_event_loop()
+        except (RuntimeError, DeprecationWarning):
+            return None
+
+class _SubCommand(NamedTuple):
+
+    cmd: AbstractCmd
+    parser: ArgumentParser
+
 class App:  # export
 
     def _add_arguments(self, parser: ArgumentParser) -> None:
-        self.__parser.add_argument(
-            '--log-flags', help = 'Log flags', default = self.__default_log_flags
+        parser.add_argument(
+            '--log-flags',
+            help = 'Log flags',
+            default = self.__default_log_flags,
+            type = parse_log_flags,
         )
-        self.__parser.add_argument(
-            '--log-level', help = 'Log level', default = self.__default_log_level
+        parser.add_argument(
+            '--log-level',
+            help = 'Log level',
+            default = self.__default_log_level,
+            type = parse_log_level,
         )
-        self.__parser.add_argument(
+        parser.add_argument(
             '--log-file', help = 'Log file', default = self.__default_log_file
         )
-        self.__parser.add_argument(
+        parser.add_argument(
             '--backtrace',
             help = 'Show exception backtraces',
             action = 'store_true',
             default = self.__back_trace,
         )
-        self.__parser.add_argument(
+        parser.add_argument(
             '--write-profile',
             help = 'Profile code and store output to file',
             default = None,
@@ -87,6 +112,45 @@ class App:  # export
         eloop: asyncio.AbstractEventLoop | None = None,
     ) -> None:
 
+        self.__args: Namespace | None = None
+        self.__cmdline: str | None = None
+        self.__description = description
+
+        self.__default_log_flags = self._default_log_flags(
+            LogFlag.STDERR | LogFlag.POSITION | LogFlag.PRIO | LogFlag.COLOR
+        )
+        if (env := os.getenv(self._default_log_flags_env(), None)) is not None:
+            self.__default_log_flags = parse_log_flags(env)
+
+        self.__default_log_level = self._default_log_level(NOTICE)
+        if (env := os.getenv(self._default_log_level_env(), None)) is not None:
+            self.__default_log_level = parse_log_level(env)
+
+        self.__default_log_file = self._default_log_file(None)
+        if (env := os.getenv(self._default_log_file_env(), None)) is not None:
+            self.__default_log_file = env
+
+        self.__back_trace = self._default_show_backtrace(False)
+        if (env := os.getenv(self._default_show_backtrace_env(), None)) is not None:
+            self.__back_trace = env.lower() in ['1', 'true']
+
+        set_log_flags(self.__default_log_flags)
+        set_log_level(self.__default_log_level)
+
+        self.__async_runner: AsyncRunner | None = None
+        self.__eloop = eloop
+        self.__own_eloop = False
+
+        cmd_classes: LoadTypes[AbstractCmd] = LoadTypes(
+            modules if modules else ['__main__'],
+            type_name_filter = name_filter,
+            type_filter = [AbstractCmd],
+        )
+        self.__cmds: list[AbstractCmd] = [cmd_class(self) for cmd_class in cmd_classes]
+        self._build_parser()
+
+    def _build_parser(self, argv: list[str] | None = None) -> None:
+
         def add_cmd_to_parser(cmd: AbstractCmd, parsers: Any) -> ArgumentParser:
             parser = cast(
                 'ArgumentParser',
@@ -112,23 +176,25 @@ class App:  # export
             if not cmds:
                 return
 
-            class SubCommand:
-
-                def __init__(self, cmd: AbstractCmd, parser: Any):
-                    self.cmd = cmd
-                    self.parser = parser
-
             title = 'Available subcommands'
             if isinstance(parent, AbstractCmd):
                 title += ' of ' + parent.name
             subparsers = parser.add_subparsers(
                 title = title, metavar = '', dest = 'command'
             )
-            scs: dict[str, SubCommand] = {}
+            scs: dict[str, _SubCommand] = {}
             for cmd in cmds:
                 cmd.set_parent(parent)
-                scs[cmd.name] = SubCommand(cmd, add_cmd_to_parser(cmd, subparsers))
+                if cmd.name in scs:
+                    log(WARNING, f'Duplicate subcommand name: {cmd.name}')
+                scs[cmd.name] = _SubCommand(cmd, add_cmd_to_parser(cmd, subparsers))
                 for alias in cmd.aliases:
+                    if alias != cmd.name and alias in scs:
+                        log(
+                            WARNING,
+                            f'Subcommand alias "{alias}" of "{cmd.name}" '
+                            'collides with an earlier subcommand',
+                        )
                     scs[alias] = scs[cmd.name]
             if all:
                 seen: set[int] = set()
@@ -139,69 +205,37 @@ class App:  # export
                             sc.cmd, sc.parser, sc.cmd.children, all = all
                         )
                 return
-            args, _ = self.__parser.parse_known_args()
+            # -- Re-parse the command line to find the invoked subcommand.
+            # This works because every level below uses dest = 'command',
+            # so each pass descends one level further into the command
+            # tree.
+            args, _ = self.__parser.parse_known_args(argv)
             cmd_name = getattr(args, 'command', None)
             if cmd_name in scs:
                 sc = scs[cmd_name]
                 add_cmds_to_parser(sc.cmd, sc.parser, sc.cmd.children, all = all)
 
-        from .Cmd import AbstractCmd
-
-        self.__args: Namespace | None = None
-        self.__cmdline: str | None = None
-
-        self.__default_log_flags = self._default_log_flags(
-            LogFlag.STDERR | LogFlag.POSITION | LogFlag.PRIO | LogFlag.COLOR
+        cmdline = sys.argv if argv is None else argv
+        if argv is None:
+            argv = sys.argv[1:]
+        add_all_parsers = (
+            '-h' in argv or '--help' in argv or '_ARGCOMPLETE' in os.environ
         )
-        if (env := os.getenv(self._default_log_flags_env(), None)) is not None:
-            self.__default_log_flags = parse_log_flags(env)
-
-        self.__default_log_level = self._default_log_level(NOTICE)
-        if (env := os.getenv(self._default_log_level_env(), None)) is not None:
-            self.__default_log_level = parse_log_level(env)
-
-        self.__default_log_file = self._default_log_file(None)
-        if (env := os.getenv(self._default_log_file_env(), None)) is not None:
-            self.__default_log_file = env
-
-        self.__back_trace = self._default_show_backtrace(False)
-        if (env := os.getenv(self._default_show_backtrace_env())) is not None:
-            self.__back_trace = env.lower() in ['1', 'true']
-
-        set_log_flags(self.__default_log_flags)
-        set_log_level(self.__default_log_level)
-
-        self.__async_runner: AsyncRunner | None = None
-        self.__eloop = eloop
-        self.__own_eloop = False
 
         self.__parser = ArgumentParser(
             formatter_class = ArgumentDefaultsHelpFormatter,
-            description = description,
+            description = self.__description,
             add_help = False,
         )
         self._add_arguments(self.__parser)
 
-        args, _ = self.__parser.parse_known_args()
+        args, _ = self.__parser.parse_known_args(argv)
         set_log_flags(args.log_flags)
         set_log_level(args.log_level)
 
-        log(DEBUG, f'-------------- Running: >{pretty_cmd(sys.argv)}<')
+        log(DEBUG, f'-------------- Running: >{pretty_cmd(cmdline)}<')
 
-        cmd_classes: LoadTypes[AbstractCmd] = LoadTypes(
-            modules if modules else ['__main__'],
-            type_name_filter = name_filter,
-            type_filter = [AbstractCmd],
-        )
-        add_all_parsers = (
-            '-h' in sys.argv or '--help' in sys.argv or '_ARGCOMPLETE' in os.environ
-        )
-        add_cmds_to_parser(
-            self,
-            self.__parser,
-            [cmd_class(self) for cmd_class in cmd_classes],
-            all = add_all_parsers,
-        )
+        add_cmds_to_parser(self, self.__parser, self.__cmds, all = add_all_parsers)
 
         # -- Add help only now, wouldn't want to have parse_known_args() exit
         # on --help with subcommands missing
@@ -210,14 +244,19 @@ class App:  # export
         )
 
     def close(self) -> None:
+        """Close the application and release all resources"""
+        if self.__async_runner is not None:
+            self.__async_runner.close()
+            self.__async_runner = None
         if self.__own_eloop:
             if self.__eloop is not None:
                 if not self.__eloop.is_closed():
                     self.__eloop.close()
                 self.__eloop = None
+            self.__own_eloop = False
 
-    async def __aenter__(self) -> None:
-        pass
+    async def __aenter__(self) -> App:
+        return self
 
     async def __aexit__(
         self,
@@ -225,7 +264,7 @@ class App:  # export
         exc: BaseException | None,
         tb: types.TracebackType | None,
     ) -> None:
-        pass
+        self.close()
 
     async def __run(self, argv: list[str] | None = None) -> None:
 
@@ -245,8 +284,10 @@ class App:  # export
 
             argcomplete.autocomplete(self.__parser, default_completer = NoopCompleter())
 
-        except Exception:
-            pass
+        except ImportError:
+            log(DEBUG, 'argcomplete is not installed, shell completion disabled')
+        except Exception as e:
+            log(DEBUG, f'Shell completion disabled: {e}')
 
         self.__args = self.__parser.parse_args(args = argv)
 
@@ -261,9 +302,17 @@ class App:  # export
             pr.enable()
 
         try:
-            ret = await self._run(self.__args)
-            if isinstance(ret, int) and ret >= 0 and ret <= 0xFF:
-                exit_status = ret
+            result = await self._run(self.__args)
+            if isinstance(result, int):
+                if 0 <= result <= 0xFF:
+                    exit_status = result
+                else:
+                    log(
+                        WARNING,
+                        f'Command returned invalid exit status {result}, '
+                        'using 1 instead',
+                    )
+                    exit_status = 1
         except Exception as e:
             log_m(ERR, f'Failed: {repr(e) if self.__back_trace else str(e)}')
             exit_status = 1
@@ -288,11 +337,11 @@ class App:  # export
     # want to do something else, for instance if you don't have sub-commands,
     # or if want to do anything before and / or after the subcommands.
     async def _run(self, args: Namespace) -> None | int:
-        if not hasattr(self.__args, 'func'):
+        if not hasattr(args, 'func'):
             self.__parser.print_help()
             return None
         # Run sub-command. Overwrite if you want to do anything before or after
-        return cast('None | int', await self.args.func(args))
+        return cast('None | int', await args.func(args))
 
     def call_async(self, awaitable: Awaitable[T], timeout: float | None = None) -> T:
         return self.async_runner.call(awaitable, timeout)
@@ -330,18 +379,25 @@ class App:  # export
         return self.__parser
 
     def run(self, argv: list[str] | None = None) -> None:
+        previous_eloop: asyncio.AbstractEventLoop | None = None
         if self.__eloop is None:
+            previous_eloop = _get_current_event_loop()
             eloop = asyncio.new_event_loop()
             asyncio.set_event_loop(eloop)
             self.__eloop = eloop
             self.__own_eloop = True
         try:
+            if argv is not None:
+                self._build_parser(argv)
             ret = self.eloop.run_until_complete(self.__run(argv))
         finally:
-            if self.__async_runner:
-                self.__async_runner.close()
-                self.__async_runner = None
             self.close()
+            # -- Restore the event loop the thread had before run(), or
+            # unset the loop if there was none.
+            if previous_eloop is not None:
+                asyncio.set_event_loop(previous_eloop)
+            else:
+                asyncio.set_event_loop(None)
         return ret
 
 

src/python/jw/pkg/lib/Cmd.py

@@ -88,7 +88,15 @@ class AbstractCmd(abc.ABC):
         self, cmds: Cmd | list[Cmd] | Types[Any] | list[Types[Any]]
     ) -> None:
         if isinstance(cmds, Cmd):
-            raise NotImplementedError('Single Cmd should be handled elsewhere')
+            if any(child.name == cmds.name for child in self.__children):
+                raise Exception(
+                    f'Can\'t register subcommand with already taken name "{cmds.name}"'
+                )
+            self.__child_classes.append(type(cmds))
+            cmds.set_parent(self)
+            self.__children.append(cmds)
+            assert len(self.__children) == len(self.__child_classes)
+            return
         if isinstance(cmds, list):
             for cmd in cmds:
                 self.add_subcommands(cmd)