Use a more flexible error handling mechanism

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

src/lxccmd/lxc

@@ -32,6 +32,7 @@ sys.path.insert(0, os.path.join(sys.path[0], os.pardir))
 
 from lxccmd.commands import get_commands
 from lxccmd.certs import generate_cert
+from lxccmd.exceptions import LXCError
 
 # Setup i18n
 _ = gettext.gettext
@@ -86,4 +87,7 @@ args = parser.parse_args()
 if args.debug:
     logging.root.setLevel(args.debug.upper())
 
-args.func(parser, args)
+try:
+    args.func(args)
+except LXCError as e:
+    parser.error(e)

src/lxccmd/lxccmd/commands/server/__init__.py

@@ -33,6 +33,7 @@
     trust_cert_add, trust_cert_list, trust_cert_remove, trust_cert_verify
 from lxccmd.config import get_run_path
 from lxccmd.cli import render_table
+from lxccmd.exceptions import LXCError
 from lxccmd.network import server_is_running
 
 try:
@@ -159,16 +160,16 @@ def cli_subparser(sp):
     sp_set.set_defaults(func=cli_set)
 
 
-def cli_status(parser, args):
+def cli_status(args):
     render_table([[_("Running"), _("Trusted clients")],
                   [str(server_is_running()),
                    ", ".join(trust_cert_list("server"))]],
                  header=True, orientation="vertical")
 
 
-def cli_start(parser, args):
+def cli_start(args):
     if server_is_running():
-        parser.error(_("A server is already running!"))
+        raise LXCError(_("A server is already running!"))
 
     # Get or generate the server certificate
     generate_cert("server")
@@ -210,14 +211,14 @@ def cli_start(parser, args):
     httpd.serve_forever()
 
 
-def cli_stop(parser, args):
+def cli_stop(args):
     if not server_is_running():
-        parser.error(_("The server isn't running at the moment!"))
+        raise LXCError(_("The server isn't running at the moment!"))
 
     server_pid_path = os.path.join(get_run_path(), "server.pid")
 
     if not os.path.exists(server_pid_path):
-        parser.error(_("No PID on record for running server!"))
+        raise LXCError(_("No PID on record for running server!"))
 
     with open(server_pid_path, "r") as fd:
         server_pid = int(fd.read().strip())
@@ -227,30 +228,30 @@ def cli_stop(parser, args):
     os.kill(server_pid, 9)
 
 
-def cli_trust(parser, args):
+def cli_trust(args):
     if not os.path.exists(args.client_cert):
-        parser.error(_("The file doesn't exist."))
+        raise LXCError(_("The file doesn't exist."))
 
     with open(args.client_cert, "r") as fd:
         certificate = fd.read()
 
     if not trust_cert_add(certificate, "server"):
-        parser.error(_("Failed to add the certificate to the trust store."))
+        raise LXCError(_("Failed to add the certificate to the trust store."))
 
 
-def cli_forget(parser, args):
+def cli_forget(args):
     if os.path.exists(args.clientid):
         with open(args.clientid, "r") as fd:
             certificate = fd.read()
     else:
         certificate = args.clientid
 
     if not trust_cert_remove(certificate, "server"):
-        parser.error(
+        raise LXCError(
             _("Failed to remove the certificate from the trust store."))
 
 
-def cli_set(parser, args):
+def cli_set(args):
     pass
 
 

src/lxccmd/lxccmd/commands/status/__init__.py

@@ -145,7 +145,7 @@ def cli_subparser(sp):
     parser.set_defaults(func=cli_status)
 
 
-def cli_status(parser, args):
+def cli_status(args):
     keys = []
     values = []
 

src/lxccmd/lxccmd/exceptions.py

@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+#
+# lxc: New LXC command line client
+#
+# Authors:
+# Stephane Graber <stgraber@ubuntu.com> (Canonical Ltd. 2014)
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+
+class LXCError(Exception):
+    pass

src/lxccmd/tests/test_command_status.py

@@ -272,7 +272,7 @@ def test_cli_status(self):
 
         sys.stdout = StringIO()
         args = parser.parse_args(["status"])
-        args.func(parser, args)
+        args.func(args)
 
         self.assertEquals(len(sys.stdout.getvalue().strip().split("\n")), 7)