Add lowest option to swift-recon disk usage output

Currently there is a "--top" option when running swift-recon for
disk usage stats. This option lists the x disks with the highest
disk usage in descending order.

This feature adds a "--lowest" option which does the opposite and
lists the y disks with lowest disk usage in ascending order.

Have also updated the docs section with --top and --lowest options

Change-Id: Ic15d407fe010a31995c2bdd9fb88548a1057f569

2 files changed, 27 insertions, 3 deletions

diff --git a/doc/manpages/swift-recon.1 b/doc/manpages/swift-recon.1
index 4311c99ad..7cafebd43 100644
--- a/doc/manpages/swift-recon.1
+++ b/doc/manpages/swift-recon.1
@@ -62,6 +62,10 @@ Get replication stats
 Check cluster for unmounted devices
 .IP "\fB-d, --diskusage\fR"
 Get disk usage stats
+.IP "\fB--top=COUNT\fR"
+Also show the top COUNT entries in rank order
+.IP "\fB--lowest=COUNT\fR"
+Also show the lowest COUNT entries in rank order
 .IP "\fB-l, --loadstats\fR"
 Get cluster load average stats
 .IP "\fB-q, --quarantined\fR"
diff --git a/swift/cli/recon.py b/swift/cli/recon.py
index b67e2678d..8c2042cb5 100755
--- a/swift/cli/recon.py
+++ b/swift/cli/recon.py
@@ -821,7 +821,7 @@ class SwiftRecon(object):
                 print("No hosts returned valid data.")
         print("=" * 79)
 
-    def disk_usage(self, hosts, top=0, human_readable=False):
+    def disk_usage(self, hosts, top=0, lowest=0, human_readable=False):
         """
         Obtain and print disk usage statistics
 
@@ -835,6 +835,7 @@ class SwiftRecon(object):
         raw_total_avail = []
         percents = {}
         top_percents = [(None, 0)] * top
+        low_percents = [(None, 100)] * lowest
         recon = Scout("diskusage", self.verbose, self.suppress_errors,
                       self.timeout)
         print("[%s] Checking disk usage now" % self._ptime())
@@ -858,6 +859,13 @@ class SwiftRecon(object):
                                 top_percents.sort(key=lambda x: -x[1])
                                 top_percents.pop()
                                 break
+                        for ident, oused in low_percents:
+                            if oused > used:
+                                low_percents.append(
+                                    (url + ' ' + entry['device'], used))
+                                low_percents.sort(key=lambda x: x[1])
+                                low_percents.pop()
+                                break
                 stats[url] = hostusage
 
         for url in stats:
@@ -903,6 +911,13 @@ class SwiftRecon(object):
                     url, device = ident.split()
                     host = urlparse(url).netloc.split(':')[0]
                     print('%.02f%%  %s' % (used, '%-15s %s' % (host, device)))
+        if low_percents:
+            print('LOWEST %s' % lowest)
+            for ident, used in low_percents:
+                if ident:
+                    url, device = ident.split()
+                    host = urlparse(url).netloc.split(':')[0]
+                    print('%.02f%%  %s' % (used, '%-15s %s' % (host, device)))
 
     def main(self):
         """
@@ -955,6 +970,9 @@ class SwiftRecon(object):
                         help="Get drive audit error stats")
         args.add_option('--top', type='int', metavar='COUNT', default=0,
                         help='Also show the top COUNT entries in rank order.')
+        args.add_option('--lowest', type='int', metavar='COUNT', default=0,
+                        help='Also show the lowest COUNT entries in rank \
+                        order.')
         args.add_option('--all', action="store_true",
                         help="Perform all checks. Equal to \t\t\t-arudlq "
                         "--md5 --sockstat --auditor --updater --expirer")
@@ -1010,7 +1028,8 @@ class SwiftRecon(object):
                 self.auditor_check(hosts)
             self.umount_check(hosts)
             self.load_check(hosts)
-            self.disk_usage(hosts, options.top, options.human_readable)
+            self.disk_usage(hosts, options.top, options.lowest,
+                            options.human_readable)
             self.get_ringmd5(hosts, swift_dir)
             self.quarantine_check(hosts)
             self.socket_usage(hosts)
@@ -1049,7 +1068,8 @@ class SwiftRecon(object):
             if options.loadstats:
                 self.load_check(hosts)
             if options.diskusage:
-                self.disk_usage(hosts, options.top, options.human_readable)
+                self.disk_usage(hosts, options.top, options.lowest,
+                                options.human_readable)
             if options.md5:
                 self.get_ringmd5(hosts, swift_dir)
                 self.get_swiftconfmd5(hosts)