syncdaemon: add monitor mode to support autorestart

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Vijay Bellur <vijay@dev.gluster.com>

BUG: 2537 (gsync autorestart)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2537

1 files changed, 54 insertions, 0 deletions

diff --git a/xlators/features/marker/utils/syncdaemon/monitor.py b/xlators/features/marker/utils/syncdaemon/monitor.py
new file mode 100644
index 000000000..3f327b6d0
--- /dev/null
+++ b/xlators/features/marker/utils/syncdaemon/monitor.py
@@ -0,0 +1,54 @@
+import os
+import sys
+import time
+import logging
+from gconf import gconf
+from syncdutils import update_file
+
+class Monitor(object):
+
+    def __init__(self):
+        self.state = None
+
+    def set_state(self, state):
+        if state == self.state:
+            return
+        self.state = state
+        logging.info('new state: %s' % state)
+        if getattr(gconf, 'state_file', None):
+            update_file(gconf.state_file, lambda f: f.write(state + '\n'))
+
+    def monitor(self):
+        argv = sys.argv[:]
+        for o in ('-N', '--no-daemon', '--monitor'):
+            while o in argv:
+                argv.remove(o)
+        argv.extend(('-N', '-p', ''))
+        argv.insert(0, os.path.basename(sys.executable))
+
+        self.set_state('starting...')
+        ret = 0
+	def nwait(p, o=0):
+            p2, r = os.waitpid(p, o)
+            if not p2:
+                return
+            if os.WIFEXITED(r):
+                return os.WEXITSTATUS(r)
+            return 1
+        while ret in (0, 1):
+            logging.info('-' * 60)
+            logging.info('starting gsyncd worker')
+            cpid = os.spawnv(os.P_NOWAIT, sys.executable, argv)
+            time.sleep(60)
+            ret = nwait(cpid, os.WNOHANG)
+            if not ret:
+                self.set_state('OK')
+                ret = nwait(cpid)
+            elif ret in (0, 1):
+                self.set_state('faulty')
+            time.sleep(10)
+        self.set_state('inconsistent')
+        return ret
+
+def monitor():
+    return Monitor().monitor()