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Diffstat (limited to 'src/silx/utils/launcher.py')
-rw-r--r-- | src/silx/utils/launcher.py | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/src/silx/utils/launcher.py b/src/silx/utils/launcher.py new file mode 100644 index 0000000..c46256a --- /dev/null +++ b/src/silx/utils/launcher.py @@ -0,0 +1,295 @@ +#!/usr/bin/env python +# coding: utf-8 +# /*########################################################################## +# +# Copyright (c) 2004-2017 European Synchrotron Radiation Facility +# +# Permission is hereby granted, free of charge, to any person obtaining a copy +# of this software and associated documentation files (the "Software"), to deal +# in the Software without restriction, including without limitation the rights +# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +# copies of the Software, and to permit persons to whom the Software is +# furnished to do so, subject to the following conditions: +# +# The above copyright notice and this permission notice shall be included in +# all copies or substantial portions of the Software. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +# THE SOFTWARE. +# +# ###########################################################################*/ +"""This module define silx application available throug the silx launcher. +""" + +__authors__ = ["P. Knobel", "V. Valls"] +__license__ = "MIT" +__date__ = "03/04/2017" + + +import sys +import importlib +import contextlib +import argparse +import logging + + +_logger = logging.getLogger(__name__) + + +class LauncherCommand(object): + """Description of a command""" + + def __init__(self, name, description=None, module_name=None, function=None): + """ + Constructor + + :param str name: Name of the command + :param str description: Description of the command + :param str module_name: Module name to execute + :param callable function: Python function to execute + """ + self.name = name + self.module_name = module_name + if description is None: + description = "A command" + self.description = description + self.function = function + + def get_module(self): + """Returns the python module to execute. If any. + + :rtype: module + """ + try: + module = importlib.import_module(self.module_name) + return module + except ImportError: + msg = "Error while reaching module '%s'" + _logger.error(msg, self.module_name, exc_info=True) + return None + + def get_function(self): + """Returns the main function to execute. + + :rtype: callable + """ + if self.function is not None: + return self.function + else: + module = self.get_module() + if module is None: + _logger.error("Impossible to load module name '%s'" % self.module_name) + return None + + # reach the 'main' function + if not hasattr(module, "main"): + raise TypeError("Module expect to have a 'main' function") + else: + main = getattr(module, "main") + return main + + @contextlib.contextmanager + def get_env(self, argv): + """Fix the environement before and after executing the command. + + :param list argv: The list of arguments (the first one is the name of + the application and command) + :rtype: int + """ + + # fix the context + old_argv = sys.argv + sys.argv = argv + + try: + yield + finally: + # clean up the context + sys.argv = old_argv + + def execute(self, argv): + """Execute the command. + + :param list[str] argv: The list of arguments (the first one is the + name of the application and command) + :rtype: int + :returns: The execution status + """ + with self.get_env(argv): + func = self.get_function() + if func is None: + _logger.error("Imposible to execute the command '%s'" % self.name) + return -1 + try: + status = func(argv) + except SystemExit as e: + # ArgumentParser likes to finish with a sys.exit + status = e.args[0] + return status + + +class Launcher(object): + """ + Manage launch of module. + + Provides an API to describe available commands and feature to display help + and execute the commands. + """ + + def __init__(self, + prog=None, + usage=None, + description=None, + epilog=None, + version=None): + """ + :param str prog: Name of the program. If it is not defined it uses the + first argument of `sys.argv` + :param str usage: Custom the string explaining the usage. Else it is + autogenerated. + :param str description: Description of the application displayed after the + usage. + :param str epilog: Custom the string displayed at the end of the help. + :param str version: Define the version of the application. + """ + if prog is None: + prog = sys.argv[0] + self.prog = prog + self.usage = usage + self.description = description + self.epilog = epilog + self.version = version + self._commands = {} + + help_command = LauncherCommand( + "help", + description="Show help of the following command", + function=self.execute_help) + self.add_command(command=help_command) + + def add_command(self, name=None, module_name=None, description=None, command=None): + """ + Add a command to the launcher. + + See also `LauncherCommand`. + + :param str name: Name of the command + :param str module_name: Module to execute + :param str description: Description of the command + :param LauncherCommand command: A `LauncherCommand` + """ + if command is not None: + assert(name is None and module_name is None and description is None) + else: + command = LauncherCommand( + name=name, + description=description, + module_name=module_name) + self._commands[command.name] = command + + def print_help(self): + """Print the help to stdout. + """ + usage = self.usage + if usage is None: + usage = "usage: {0.prog} [--version|--help] <command> [<args>]" + description = self.description + epilog = self.epilog + if epilog is None: + epilog = "See '{0.prog} help <command>' to read about a specific subcommand" + + print(usage.format(self)) + print("") + if description is not None: + print(description) + print("") + print("The {0.prog} commands are:".format(self)) + commands = sorted(self._commands.keys()) + for command in commands: + command = self._commands[command] + print(" {:10s} {:s}".format(command.name, command.description)) + print("") + print(epilog.format(self)) + + def execute_help(self, argv): + """Execute the help command. + + :param list[str] argv: The list of arguments (the first one is the + name of the application with the help command) + :rtype: int + :returns: The execution status + """ + description = "Display help information about %s" % self.prog + parser = argparse.ArgumentParser(description=description) + parser.add_argument( + 'command', + default=None, + nargs=argparse.OPTIONAL, + help='Command in which aving help') + + try: + options = parser.parse_args(argv[1:]) + except SystemExit as e: + # ArgumentParser likes to finish with a sys.exit + return e.args[0] + + command_name = options.command + if command_name is None: + self.print_help() + return 0 + + if command_name not in self._commands: + print("Unknown command: %s", command_name) + self.print_help() + return -1 + + command = self._commands[command_name] + prog = "%s %s" % (self.prog, command.name) + return command.execute([prog, "--help"]) + + def execute(self, argv=None): + """Execute the launcher. + + :param list[str] argv: The list of arguments (the first one is the + name of the application) + :rtype: int + :returns: The execution status + """ + if argv is None: + argv = sys.argv + + if len(argv) <= 1: + self.print_help() + return 0 + + command_name = argv[1] + + if command_name == "--version": + print("%s version %s" % (self.prog, str(self.version))) + return 0 + + if command_name in ["--help", "-h"]: + # Special help command + if len(argv) == 2: + self.print_help() + return 0 + else: + command_name = argv[2] + command_argv = argv[2:] + ["--help"] + command_argv[0] = "%s %s" % (self.prog, command_argv[0]) + else: + command_argv = argv[1:] + command_argv[0] = "%s %s" % (self.prog, command_argv[0]) + + if command_name not in self._commands: + print("Unknown command: %s" % command_name) + self.print_help() + return -1 + + command = self._commands[command_name] + return command.execute(command_argv) |