Adding Multipath Module

avocado.utils.multipath: Adds multipath related modules.
Signed-off-by: NNarasimhan V <sim@linux.vnet.ibm.com>

avocado/utils/multipath.py

+# 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 LICENSE for more details.
+#
+# Copyright: 2016 IBM
+# Author: Narasimhan V <sim@linux.vnet.ibm.com>
+
+"""
+Module with multipath related utility functions.
+It needs root access.
+"""
+
+import time
+import logging
+from . import distro
+from . import process
+from . import service
+
+
+def get_svc_name():
+    """
+    Gets the multipath service name based on distro.
+    """
+    if distro.detect().name == 'Ubuntu':
+        return "multipath-tools"
+    else:
+        return "multipathd"
+
+
+def form_conf_mpath_file(blacklist="", defaults_extra=""):
+    """
+    Form a multipath configuration file, and restart multipath service.
+
+    :parm blacklist: Entry in conf file to indicate blacklist section.
+    :parm defaults_extra: Extra entry in conf file in defaults section.
+    """
+    conf_file = "/etc/multipath.conf"
+    with open(conf_file, "w") as mpath_fp:
+        mpath_fp.write("defaults {\n")
+        mpath_fp.write("    find_multipaths yes\n")
+        mpath_fp.write("    user_friendly_names yes\n")
+        if defaults_extra:
+            mpath_fp.write("    %s\n" % defaults_extra)
+        mpath_fp.write("}\n")
+        if blacklist:
+            mpath_fp.write("blacklist {\n")
+            mpath_fp.write("    %s\n" % blacklist)
+            mpath_fp.write("}\n")
+    logging.debug(open(conf_file, "r").read())
+    # The reason for sleep here is to give some time for change in
+    # multipath.conf file to take effect.
+    time.sleep(5)
+    service.SpecificServiceManager(get_svc_name()).restart()
+
+
+def device_exists(path):
+    """
+    Checks if a given path exists.
+
+    :return: True if path exists, False if does not exist.
+    """
+    cmd = "multipath -l %s" % path
+    if process.system(cmd, ignore_status=True, sudo=True) != 0:
+        return False
+    return True
+
+
+def get_mpath_name(wwid):
+    """
+    Get multipath name for a given wwid.
+
+    :parm wwid: wwid of multipath device.
+
+    :return: Name of multipath device.
+    """
+    if device_exists(wwid):
+        cmd = "multipath -l %s" % wwid
+        return process.system_output(cmd, sudo=True).split()[0]
+
+
+def get_multipath_wwids():
+    """
+    Get list of multipath wwids.
+
+    :return: List of multipath wwids.
+    """
+    cmd = "egrep -v '^($|#)' /etc/multipath/wwids"
+    wwids = process.system_output(cmd, ignore_status=True, sudo=True)
+    wwids = wwids.strip("\n").replace("/", "").split("\n")
+    return wwids
+
+
+def get_paths(wwid):
+    """
+    Get list of paths, given a multipath wwid.
+
+    :return: List of paths.
+    """
+    if not device_exists(wwid):
+        return
+    cmd = "multipath -ll %s" % wwid
+    lines = process.system_output(cmd, sudo=True).strip("\n")
+    paths = []
+    for line in lines.split("\n"):
+        if not (('size' in line) or ('policy' in line) or (wwid in line)):
+            paths.append(line.split()[-5])
+    return paths
+
+
+def get_policy(wwid):
+    """
+    Gets path_checker policy, given a multipath wwid.
+
+    :return: path checker policy.
+    """
+    if device_exists(wwid):
+        cmd = "multipath -ll %s" % wwid
+        lines = process.system_output(cmd, sudo=True).strip("\n")
+        for line in lines.split("\n"):
+            if 'policy' in line:
+                return line.split("'")[1].split()[0]
+
+
+def get_size(wwid):
+    """
+    Gets size of device, given a multipath wwid.
+
+    :return: size of multipath device.
+    """
+    if device_exists(wwid):
+        cmd = "multipath -ll %s" % wwid
+        lines = process.system_output(cmd, sudo=True).strip("\n")
+        for line in lines.split("\n"):
+            if 'size' in line:
+                return line.split("=")[1].split()[0]
+
+
+def flush_path(path_name):
+    """
+    Flushes the given multipath.
+
+    :return: Returns False if command fails, True otherwise.
+    """
+    cmd = "multipath -f %s" % path_name
+    if process.system(cmd, ignore_status=True, sudo=True) != 0:
+        return False
+    return True