config: backup when current config is different from recent backup copy

With this change,
when '/etc/target/saveconfig.json' is same as '/etc/target/backup/saveconfig-${latest-stamp}.json
we skip backing up saveconfig.json

Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

1 files changed, 29 insertions, 24 deletions

diff --git a/targetcli/ui_root.py b/targetcli/ui_root.py
index 33bb948..f398395 100644
--- a/targetcli/ui_root.py
+++ b/targetcli/ui_root.py
@@ -23,6 +23,7 @@ import os
 import re
 import shutil
 import stat
+import filecmp
 
 from configshell_fb import ExecutionError
 from rtslib_fb import RTSRoot
@@ -85,32 +86,36 @@ class UIRoot(UINode):
                 except OSError as exe:
                     raise ExecutionError("Cannot create backup directory [%s] %s." % (backup_dir, exc.strerror))
 
+            # Only save backups if savefile exits
             if os.path.exists(savefile):
-                try:
-                    shutil.copy(savefile, backupfile)
-                except IOError as ioe:
-                    backup_error = ioe.strerror or "Unknown error"
-
-                if backup_error == None:
-                    # Kill excess backups
+                backed_files_list = sorted(glob(os.path.dirname(savefile) + "/backup/*.json"))
+                # Save backup if 1. backup dir is empty, or 2. savefile is differnt from recent backup copy
+                if not backed_files_list or not filecmp.cmp(backed_files_list[-1], savefile):
                     try:
-                        with open(universal_prefs_file) as prefs:
-                            backups = [line for line in prefs.read().splitlines() if re.match('^kept_backups\s*=', line)]
-                            kept_backups = int(backups[0].split('=')[1].strip())
-                    except:
-                        kept_backups = default_kept_backups
-
-                    backups = sorted(glob(os.path.dirname(savefile) + "/backup/*.json"))
-                    files_to_unlink = list(reversed(backups))[kept_backups:]
-                    for f in files_to_unlink:
-                        with ignored(IOError):
-                            os.unlink(f)
-
-                    self.shell.log.info("Last %d configs saved in %s." % \
-                                        (kept_backups, backup_dir))
-                else:
-                    self.shell.log.warning("Could not create backup file %s: %s." % \
-                                           (backupfile, backup_error))
+                        shutil.copy(savefile, backupfile)
+
+                    except IOError as ioe:
+                        backup_error = ioe.strerror or "Unknown error"
+
+                    if backup_error == None:
+                        # Kill excess backups
+                        try:
+                            with open(universal_prefs_file) as prefs:
+                                backups = [line for line in prefs.read().splitlines() if re.match('^kept_backups\s*=', line)]
+                                kept_backups = int(backups[0].split('=')[1].strip())
+                        except:
+                            kept_backups = default_kept_backups
+
+                        files_to_unlink = list(reversed(backed_files_list))[kept_backups:]
+                        for f in files_to_unlink:
+                            with ignored(IOError):
+                                os.unlink(f)
+
+                        self.shell.log.info("Last %d configs saved in %s." % \
+                                            (kept_backups, backup_dir))
+                    else:
+                        self.shell.log.warning("Could not create backup file %s: %s." % \
+                                               (backupfile, backup_error))
 
         self.rtsroot.save_to_file(savefile)