join: Throw CommandError instead of Exception for simple errors

Throwing an exception here still dumps out the Python stack trace, which
can be a little disconcerting for users.

In this case, the stack trace isn't going to really help at all (the
problem is pretty obvious), and it obscures the useful message
explaining what went wrong.

Throw a CommandError instead, which samba-tool will catch and display
more nicely.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13747

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Rowland Penny <rpenny@samba.org>
Reviewed-by: Jeremy Allison <rpenny@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Wed Jan 16 22:11:04 CET 2019 on sn-devel-144

(cherry picked from commit 9e4b08f4c384b8cae5ad853a7be7cf03e2749be5)

diff --git a/python/samba/join.py b/python/samba/join.py
index 32fac680b1f1ab1d0538d2d8da270e6184fabc41..d577df0706991bc620937a089b89d30f73f36284 100644 (file)
--- a/python/samba/join.py
+++ b/python/samba/join.py
@@ -42,6 +42,7 @@ import logging
 import talloc
 import random
 import time
+from samba.netcmd import CommandError
 
 class DCJoinException(Exception):
 
@@ -337,10 +338,10 @@ class dc_join(object):
         try:
             ctx.cldap_ret = ctx.net.finddc(domain=domain, flags=nbt.NBT_SERVER_LDAP | nbt.NBT_SERVER_DS | nbt.NBT_SERVER_WRITABLE)
         except NTSTATUSError as error:
-            raise Exception("Failed to find a writeable DC for domain '%s': %s" %
-                            (domain, error.args[1]))
+            raise CommandError("Failed to find a writeable DC for domain '%s': %s" %
+                               (domain, error.args[1]))
         except Exception:
-            raise Exception("Failed to find a writeable DC for domain '%s'" % domain)
+            raise CommandError("Failed to find a writeable DC for domain '%s'" % domain)
         if ctx.cldap_ret.client_site is not None and ctx.cldap_ret.client_site != "":
             ctx.site = ctx.cldap_ret.client_site
         return ctx.cldap_ret.pdc_dns_name