geo-rep: Config file upgrade

When old config file is used with new geo-rep, config item like
'georep_session_working_dir' was missing in old config file.

With this patch geo-rep sets the default value for new items.

Following config options supported:
  - georep_session_working_dir
  - gluster_params
  - ssh_command_tar

BUG: 1036539
Change-Id: I389c62e749f3b567f9ecf96d4b41367ef962c025
Signed-off-by: Aravinda VK <avishwan@redhat.com>
Reviewed-on: http://review.gluster.org/6934
Reviewed-by: Venky Shankar <vshankar@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

geo-replication/syncdaemon/configinterface.py

@@ -9,6 +9,8 @@ import os
 import errno
 import sys
 from stat import ST_DEV, ST_INO, ST_MTIME
+import tempfile
+import shutil
 
 from syncdutils import escape, unescape, norm, update_file, GsyncdError
 
@@ -19,6 +21,56 @@ config_version = 2.0
 re_type = type(re.compile(''))
 
 
+
+# (SECTION, OPTION, OLD VALUE, NEW VALUE)
+CONFIGS = (
+    ("peersrx . .", "georep_session_working_dir", "", "/var/lib/glusterd/geo-replication/${mastervol}_${remotehost}_${slavevol}/"),
+    ("peersrx .", "gluster_params", "aux-gfid-mount xlator-option=\*-dht.assert-no-child-down=true", "aux-gfid-mount"),
+    ("peersrx . .", "ssh_command_tar", "", "ssh -oPasswordAuthentication=no -oStrictHostKeyChecking=no -i /var/lib/glusterd/geo-replication/tar_ssh.pem"),
+)
+
+def upgrade_config_file(path):
+    config_change = False
+    config = ConfigParser.RawConfigParser()
+    config.read(path)
+
+    for sec, opt, oldval, newval in CONFIGS:
+        try:
+            val = config.get(sec, opt)
+        except ConfigParser.NoOptionError:
+            # if new config opt not exists
+            config_change = True
+            config.set(sec, opt, newval)
+            continue
+        except ConfigParser.Error:
+            """
+            When gsyncd invoked at the time of create, config file
+            will not be their. Ignore any ConfigParser errors
+            """
+            continue
+
+        if val == newval:
+            # value is same as new val
+            continue
+
+        if val == oldval:
+            # config value needs update
+            config_change = True
+            config.set(sec, opt, newval)
+
+    if config_change:
+        tempConfigFile = tempfile.NamedTemporaryFile(mode="wb", delete=False)
+        with open(tempConfigFile.name, 'wb') as configFile:
+            config.write(configFile)
+
+        # If src and dst are two different file system, then os.rename
+        # fails, In this case if temp file created in /tmp and if /tmp is
+        # seperate fs then os.rename gives following error, so use shutil
+        # OSError: [Errno 18] Invalid cross-device link
+        # mail.python.org/pipermail/python-list/2005-February/342893.html
+        shutil.move(tempConfigFile.name, path)
+
+
 class MultiDict(object):
     """a virtual dict-like class which functions as the union of underlying dicts"""
 

geo-replication/syncdaemon/gsyncd.py

@@ -20,7 +20,7 @@ from ipaddr import IPAddress, IPNetwork
 from gconf import gconf
 from syncdutils import FreeObject, norm, grabpidfile, finalize, log_raise_exception
 from syncdutils import GsyncdError, select, set_term_handler, privileged, update_file
-from configinterface import GConffile
+from configinterface import GConffile, upgrade_config_file
 import resource
 from monitor import monitor
 
@@ -371,6 +371,8 @@ def main_i():
                     namedict['remotehost'] = x.remotehost
     if not 'config_file' in rconf:
         rconf['config_file'] = os.path.join(os.path.dirname(sys.argv[0]), "conf/gsyncd_template.conf")
+
+    upgrade_config_file(rconf['config_file'])
     gcnf = GConffile(rconf['config_file'], canon_peers, defaults.__dict__, opts.__dict__, namedict)
 
     checkpoint_change = False