Add helper to handle CLIs that optionally spawn several jobs

This helper function detects whether an opcode returned a list of jobs
(i.e., a result of the type ht.TJobIdListOnly) and in this case it
uses 'ganeti.cli.JobExecutor' to wait for the jobs and determine the
return code which is based on the return codes of all jobs.
Signed-off-by: Jose A. Lopes <jabolopes@google.com>
Reviewed-by: Helga Velroyen <helgav@google.com>

Makefile.am

@@ -373,6 +373,7 @@ pkgpython_PYTHON = \
 
 client_PYTHON = \
 	lib/client/__init__.py \
+	lib/client/base.py \
 	lib/client/gnt_backup.py \
 	lib/client/gnt_cluster.py \
 	lib/client/gnt_debug.py \

lib/client/base.py

+#
+#
+
+# Copyright (C) 2014 Google Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301, USA.
+
+
+"""Utils for CLI commands"""
+
+from ganeti import cli
+from ganeti import constants
+from ganeti import ht
+
+
+def GetResult(cl, opts, result):
+  """Waits for jobs and returns whether they have succeeded
+
+  Some OpCodes return of list of jobs.  This function can be used
+  after issueing a given OpCode to look at the OpCode's result and, if
+  it is of type L{ht.TJobIdListOnly}, then it will wait for the jobs
+  to complete, otherwise just return L{constants.EXIT_SUCCESS}.
+
+  @type cl: L{ganeti.luxi.Client}
+  @param cl: client that was used to submit the OpCode, which will
+             also be used to poll the jobs
+
+  @param opts: CLI options
+
+  @param result: result of the opcode which might contain job
+         information, in which case the jobs will be polled, or simply
+         the result of the opcode
+
+  @rtype: int
+  @return: L{constants.EXIT_SUCCESS} if all jobs completed
+           successfully, L{constants.EXIT_FAILURE} otherwise
+
+  """
+  if not ht.TJobIdListOnly(result):
+    return constants.EXIT_SUCCESS
+
+  jex = cli.JobExecutor(cl=cl, opts=opts)
+
+  for (status, job_id) in result[constants.JOB_IDS_KEY]:
+    jex.AddJobId(None, status, job_id)
+
+  bad_jobs = [job_result
+              for success, job_result in jex.GetResults()
+              if not success]
+
+  if len(bad_jobs) > 0:
+    for job in bad_jobs:
+      cli.ToStdout("Job failed, result is '%s'.", job)
+    cli.ToStdout("%s job(s) failed.", bad_jobs)
+    return constants.EXIT_FAILURE
+  else:
+    return constants.EXIT_SUCCESS