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

diff --git a/python/samba/join.py b/python/samba/join.py
index 28b7f0b8300f5f7fd8a980375a22e8c12ec68bac..da8dcb050d322272414550b2660f550702a03e74 100644 (file)
--- a/python/samba/join.py
+++ b/python/samba/join.py
@@ -50,6 +50,7 @@ import os
 import tempfile
 from samba.compat import text_type
 from samba.compat import get_string
+from samba.netcmd import CommandError
 
 
 class DCJoinException(Exception):
@@ -345,10 +346,10 @@ class DCJoinContext(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