[nfs-utils PATCH v2 09/17] mountstats: Add support for -S/--since to the mountstats and ms-iostat commands

[Scott Mayhew <smayhew@redhat.com>]

Add support for -S/--since to the mountstats and ms-iostat commands to
display the delta between a previous copy of /proc/self/mountstats and
the current /proc/self/mountstats file.  Can be combined with the -f
option to show the statistics between two different points in time.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 tools/mountstats/mountstats.py | 50 +++++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/tools/mountstats/mountstats.py b/tools/mountstats/mountstats.py
index ddaa6c4..fac7853 100644
--- a/tools/mountstats/mountstats.py
+++ b/tools/mountstats/mountstats.py
@@ -548,11 +548,28 @@ def parse_stats_file(f):
 
     return ms_dict
 
+def print_mountstats(stats, nfs_only, rpc_only):
+    if nfs_only:
+       stats.display_nfs_options()
+       stats.display_nfs_events()
+       stats.display_nfs_bytes()
+    elif rpc_only:
+       stats.display_rpc_generic_stats()
+       stats.display_rpc_op_stats()
+    else:
+       stats.display_nfs_options()
+       stats.display_nfs_bytes()
+       stats.display_rpc_generic_stats()
+       stats.display_rpc_op_stats()
+
 def mountstats_command(args):
     """Mountstats command
     """
     mountstats = parse_stats_file(args.infile)
 
+    if args.since:
+        old_mountstats = parse_stats_file(args.since)
+
     for mp in args.mountpoints:
         if mp not in mountstats:
             print('Statistics for mount point %s not found' % mp)
@@ -565,20 +582,19 @@ def mountstats_command(args):
             print('Mount point %s exists but is not an NFS mount' % mp)
             continue
 
-        if args.nfs_only:
-           stats.display_nfs_options()
-           stats.display_nfs_events()
-           stats.display_nfs_bytes()
-        elif args.rpc_only:
-           stats.display_rpc_generic_stats()
-           stats.display_rpc_op_stats()
+        if not args.since:
+            print_mountstats(stats, args.nfs_only, args.rpc_only)
+        elif args.since and mp not in old_mountstats:
+            print_mountstats(stats, args.nfs_only, args.rpc_only)
         else:
-           stats.display_nfs_options()
-           stats.display_nfs_bytes()
-           stats.display_rpc_generic_stats()
-           stats.display_rpc_op_stats()
+            old_stats = DeviceData()
+            old_stats.parse_stats(old_mountstats[mp])
+            diff_stats = stats.compare_iostats(old_stats)
+            print_mountstats(diff_stats, args.nfs_only, args.rpc_only)
 
     args.infile.close()
+    if args.since:
+        args.since.close()
 
 def nfsstat_command(args):
     return
@@ -601,6 +617,11 @@ def iostat_command(args):
     mountstats = parse_stats_file(args.infile)
     devices = args.mountpoints
 
+    if args.since:
+        old_mountstats = parse_stats_file(args.since)
+    else:
+        old_mountstats = None
+
     # make certain devices contains only NFS mount points
     if len(devices) > 0:
         check = []
@@ -623,7 +644,6 @@ def iostat_command(args):
         print('No NFS mount points were found')
         return
 
-    old_mountstats = None
     sample_time = 0
 
     if args.interval is None:
@@ -648,6 +668,8 @@ def iostat_command(args):
             mountstats = parse_stats_file(args.infile)
 
     args.infile.close()
+    if args.since:
+        args.since.close()
 
 class ICMAction(argparse.Action):
     """Custom action to deal with interval, count, and mountpoints.
@@ -667,7 +689,7 @@ class ICMAction(argparse.Action):
         try:
             intval = int(value)
             if namespace.infile.name != '/proc/self/mountstats':
-                raise argparse.ArgumentError(self, "not allowed with argument -f/--file")
+                raise argparse.ArgumentError(self, "not allowed with argument -f/--file or -S/--since")
             self._handle_int(namespace, intval)
         except ValueError:
             namespace.mountpoints.append(value)
@@ -686,6 +708,8 @@ def main():
     parser.add_argument('-f', '--file', default=open('/proc/self/mountstats', 'r'),
         type=argparse.FileType('r'), dest='infile',
         help='Read stats from %(dest)s instead of /proc/self/mountstats')
+    parser.add_argument('-S', '--since', type=argparse.FileType('r'),
+        help='Show difference between current stats and those in SINCE')
 
     prog = os.path.basename(sys.argv[0])
 
-- 
1.9.3