Add control handling logic

src/control.py

@@ -0,0 +1,65 @@
+"""compctl
+
+Usage:
+  compctl halt
+  compctl usage
+
+"""
+
+import shlex
+import re
+from docopt import docopt, DocoptExit
+
+class CommandError(Exception):
+    pass
+
+def parse(cmd):
+    parts = shlex.split(cmd)
+    try:
+        options = docopt(__doc__, argv = parts,
+                         help = False, version = None)
+        return options
+    except DocoptExit:
+        raise CommandError()
+
+HANDLERS = {}
+
+def handler(subcommand):
+    def wrapper(fn):
+        HANDLERS[subcommand] = fn
+        return fn
+    return wrapper
+
+def dispatch(options, responder):
+    for name, callback in HANDLERS.iteritems():
+        if options[name]:
+            callback(responder, options)
+            return
+    raise CommandError()
+
+@handler('usage')
+def handle_usage(responder, opts):
+    regex = re.compile('  compctl (.*)')
+    for line in __doc__.split('\n')[3:]:
+        match = regex.match(line)
+        if match:
+            responder('Usage: {0}'.format(match.group(1)))
+
+@handler('halt')
+def halt_system(responder, options):
+    import sys
+    responder("System going down for halt")
+    sys.exit(0)
+
+def default_responder(output):
+    print output
+
+def handle(cmd, responder = default_responder, no_auto_fail = False):
+    try:
+        dispatch(parse(cmd), responder)
+    except CommandError:
+        if no_auto_fail:
+            raise
+        else:
+            handle('usage', responder, no_auto_fail = True)
+

src/test_control.py

@@ -0,0 +1,30 @@
+import control
+import mock
+import sys
+
+def test_halt_parse():
+    options = control.parse('halt')
+    assert options['halt']
+
+def check_showed_usage(responder):
+    responder.assert_any_call('Usage: halt')
+    responder.assert_any_call('Usage: usage')
+
+def test_usage():
+    responder = mock.Mock()
+    control.handle('usage', responder)
+    check_showed_usage(responder)
+
+def test_halt():
+    exit_handler = mock.Mock()
+    responder = mock.Mock()
+    with mock.patch('sys.exit', exit_handler):
+        control.handle('halt', responder)
+        responder.assert_called_once_with('System going down for halt')
+        exit_handler.assert_called_once_with(0)
+
+def test_unknown():
+    responder = mock.Mock()
+    control.handle('hnnnng', responder)
+    check_showed_usage(responder)
+