added option for testing a cluster rather than list of individual ser…

…vers

README.textile

@@ -88,6 +88,8 @@ Options:
   -h, --help            show this help message and exit
   --servers=SERVERS     comma separated list of host:port (default
                         localhost:2181)
+  --cluster=CLUSTER     comma separated list of host:port, test as a cluster,
+                        alternative to --servers
   --timeout=TIMEOUT     session timeout in milliseconds (default 5000)
   --root_znode=ROOT_ZNODE
                         root for the test, will be created as part of test
@@ -108,6 +110,8 @@ Options:
   -q, --quiet           quiet output, basically just success/failure
 </pre>
 
+The --servers options will test each server in turn while the --cluster option tests a server in the cluster chosen at random.
+
 <code>
 PYTHONPATH=lib.linux-i686-2.6 LD_LIBRARY_PATH=lib.linux-i686-2.6 ./zk-latencies.py --servers "host:port(,host:port)*"
 </code>

zk-latencies.py

@@ -25,7 +25,9 @@
 usage = "usage: %prog [options]"
 parser = OptionParser(usage=usage)
 parser.add_option("", "--servers", dest="servers",
-                  default="localhost:2181", help="comma separated list of host:port (default localhost:2181)")
+                  default="localhost:2181", help="comma separated list of host:port (default localhost:2181), test each in turn")
+parser.add_option("", "--cluster", dest="cluster",
+                  default=None, help="comma separated list of host:port, test as a cluster, alternative to --servers")
 parser.add_option("", "--timeout", dest="timeout", type="int",
                   default=5000, help="session timeout in milliseconds (default 5000)")
 parser.add_option("", "--root_znode", dest="root_znode",
@@ -261,14 +263,17 @@ def func():
 
 if __name__ == '__main__':
     data = options.znode_size * "x"
-    servers = options.servers.split(",")
+    if options.cluster:
+        servers = [options.cluster]
+    else:
+        servers = options.servers.split(",")
 
     # create all the sessions first to ensure that all servers are
     # at least available & quorum has been formed. otw this will 
     # fail right away (before we start creating nodes)
     sessions = []
     # create one session to each of the servers in the ensemble
-    for i, server in enumerate(servers):
+    for server in servers:
         sessions.append(ZKClient(server, options.timeout))
 
     # ensure root_znode doesn't exist