add aliases and command help functions

config.json

@@ -5,6 +5,15 @@
     "update": "core/update.sh",
     "version": "core/version.sh",
     "commands_help": {
-        "core" :"Core functions of webis command.",
+        "core": "Core functions of webis command.",
+        "test": "A few unimportant test scripts for developing purpose.",
+        "betamng": "Low level scripts for managing betaweb.",
+        "betaweb": "High level scripts for betaweb, e.g. hadoop management."
+    },
+
+    "commands_aliases": {
+        "core": ["co"],
+        "betamng": ["bm"],
+        "betaweb": ["bw"]
     }
 }
\ No newline at end of file

libs/lib.py

@@ -6,9 +6,39 @@
     contact: stg7@gmx.de
     2015
 """
-import re
 import os
+import argparse
 
+class AliasedSubParsersAction(argparse._SubParsersAction):
+    """ Based on : https://gist.github.com/sampsyo/471779 """
+    class _AliasedPseudoAction(argparse.Action):
+        def __init__(self, name, aliases, help):
+            dest = name
+            if aliases:
+                dest += ' (%s)' % ','.join(aliases)
+            sup = super(AliasedSubParsersAction._AliasedPseudoAction, self)
+            sup.__init__(option_strings=[], dest=dest, help=help)
+
+    def add_parser(self, name, **kwargs):
+        if 'aliases' in kwargs:
+            aliases = kwargs['aliases']
+            del kwargs['aliases']
+        else:
+            aliases = []
+
+        parser = super(AliasedSubParsersAction, self).add_parser(name, **kwargs)
+
+        # Make the aliases work.
+        for alias in aliases:
+            self._name_parser_map[alias] = parser
+        # Make the help text reflect them, first removing old help entry.
+        if 'help' in kwargs:
+            help = kwargs.pop('help')
+            self._choices_actions.pop()
+            pseudo_action = self._AliasedPseudoAction(name, aliases, help)
+            self._choices_actions.append(pseudo_action)
+
+        return parser
 
 if __name__ == "__main__":
     print("\033[91m[ERROR]\033[0m lib is not a standalone module")

webis.py

@@ -18,6 +18,18 @@ from log import *
 from system import *
 
 
+def check_commands_alias_definition(config):
+    """Checks if the command alias definition has no collisions."""
+    aliashisto = {}
+    for command in config["commands_aliases"]:
+        for alias in config["commands_aliases"][command]:
+            aliashisto[alias] = aliashisto.get(alias, 0) + 1
+
+    if len(config["commands_aliases"].keys()) != len(aliashisto.keys()):
+        lError("Commands alias definition has collisions, please fix it.")
+        sys.exit(1)
+
+
 def load_config():
     """Returns the configuration, based on the JSON configuration file."""
     try:
@@ -86,22 +98,36 @@ def run_subcommand(subcommand, subcommandpath, params=[]):
         lError("An error occurred while executing " + cmd)
     return return_value
 
+def translate_alias_to_command(config, alias):
+    """Transforms a given alias to the unique command."""
+    for command in config["commands_aliases"]:
+        if alias in config["commands_aliases"][cmd]:
+            return command
+
 
 def main(args):
     config = load_config()
+    check_commands_alias_definition(config)
+
     commands = get_commands(config)
     parser = argparse.ArgumentParser()
+    parser.register('action', 'parsers', AliasedSubParsersAction)
+
     subparsers = {}
     allcommands = {}
     commandparsers = parser.add_subparsers(
         metavar='<command>', dest='<command>', help='Available commands:')
     for command in commands:
-        # TODO: It is unclear where to obtain the help messages for commands.
-        # TODO: It is conceivable to introduce aliases for each command, but it
-        # is unclear where to obtain them. Simply using a prefix does not
-        # work for betamng and betaweb, since they share a long prefix.
+        help_msg = config["commands_help"].get(
+            command,
+            colorred(
+                "Please add a short description of {} "
+                "in config.json[commands_help].".format(command)))
+
         commandparser = commandparsers.add_parser(
-            command, help='TODO: Help message for commands.')
+            command, aliases=config["commands_aliases"].get(command, []),
+            help=help_msg)
+
         subparsers[command] = commandparser
         subcommandparsers = commandparser.add_subparsers(
             metavar='<subcommand>', dest='<subcommand>',
@@ -124,7 +150,11 @@ def main(args):
     parameter = parseresults[1]
 
     if len(argsdict) == 2 and argsdict['<subcommand>'] is None:
-        subparsers[argsdict['<command>']].print_help()
+        command = argsdict['<command>']
+        if command not in subparsers:
+            command = translate_alias_to_command(command)
+
+        subparsers[command].print_help()
         return 0
 
     return run_subcommand(