geo-rep: Upgrading config file to new version

- configuration handling is enhanced with patch
https://review.gluster.org/#/c/glusterfs/+/18257/
- hence, the old configurations are not applied when
Geo-rep session is created in the old version and upgraded.

This patch solves the issue. It,
- checks if the config file is old.
- parses required values from old config file and stores in new
  config file, which ensures that configerations are applied on
  upgrade.
- stores old config file as backup.
- handles changes in options introduced in
  https://review.gluster.org/#/c/glusterfs/+/18257/

Backport of:
 > Patch: https://review.gluster.org/22894
 > BUG: bz#1707731
 > Change-Id: Iad8da6c1e1ae8ecf7c84dfdf8ea3ac6966d8a2a0
 > Signed-off-by: Shwetha K Acharya <sacharya@redhat.com>

updates: bz#1764171
Change-Id: Iad8da6c1e1ae8ecf7c84dfdf8ea3ac6966d8a2a0
Signed-off-by: Kotresh HR <khiremat@redhat.com>

2 files changed, 46 insertions, 0 deletions

diff --git a/geo-replication/syncdaemon/gsyncd.py b/geo-replication/syncdaemon/gsyncd.py
index effe0ce6aa2..a4c6f32f135 100644
--- a/geo-replication/syncdaemon/gsyncd.py
+++ b/geo-replication/syncdaemon/gsyncd.py
@@ -253,6 +253,11 @@ def main():
     if args.subcmd == "slave":
         override_from_args = True
 
+    if args.subcmd == "monitor":
+        ret = gconf.is_config_file_old(config_file, args.master, extra_tmpl_args["slavevol"])
+        if ret is not None:
+           gconf.config_upgrade(config_file, ret)
+
     # Load Config file
     gconf.load(GLUSTERFS_CONFDIR + "/gsyncd.conf",
                config_file,
diff --git a/geo-replication/syncdaemon/gsyncdconfig.py b/geo-replication/syncdaemon/gsyncdconfig.py
index 26fb6a57318..68d1b489e23 100644
--- a/geo-replication/syncdaemon/gsyncdconfig.py
+++ b/geo-replication/syncdaemon/gsyncdconfig.py
@@ -14,6 +14,7 @@ try:
 except ImportError:
     from configparser import ConfigParser, NoSectionError
 import os
+import shutil
 from string import Template
 from datetime import datetime
 
@@ -328,6 +329,46 @@ class Gconf(object):
 
         return False
 
+def is_config_file_old(config_file, mastervol, slavevol):
+    cnf = ConfigParser()
+    cnf.read(config_file)
+    session_section = "peers %s %s" % (mastervol, slavevol)
+    try:
+        return dict(cnf.items(session_section))
+    except NoSectionError:
+        return None
+
+def config_upgrade(config_file, ret):
+    config_file_backup = os.path.join(os.path.dirname(config_file), "gsyncd.conf.bkp")
+
+    #copy old config file in a backup file
+    shutil.copyfile(config_file, config_file_backup)
+
+    #write a new config file
+    config = ConfigParser()
+    config.add_section('vars')
+
+    for key, value in ret.items():
+        #handle option name changes
+        if key == "use_tarssh":
+            new_key = "sync-method"
+            if value == "true":
+                new_value = "tarssh"
+            else:
+                new_value = "rsync"
+                config.set('vars', new_key, new_value)
+
+        if key == "timeout":
+            new_key = "slave-timeout"
+            config.set('vars', new_key, value)
+
+        #for changes like: ignore_deletes to ignore-deletes
+        new_key = key.replace("_", "-")
+        config.set('vars', new_key, value)
+
+    with open(config_file, 'w') as configfile:
+        config.write(configfile)
+
 
 def validate_int(value):
     try: