Test - IP allocation simulation - add -e option to run the daemon's algorithm

A recent change in the deamon's (i.e. real) IP allocation algorithm
uses qsort(3).  This makes it very difficult to get the same results
in Python, since qsort's behaviour on identical keys is undefined.

Add a -e option to run "../bin/ctdb_takeover_tests ctdb_takeover_run_core"
instead of the internal Python algorithm.  We pass the current cluster
state and read it back from the output of the test program.

This is currently a rough hack.  Perhaps it'll be improved later...
:-)

Signed-off-by: Martin Schwenke <martin@meltin.net>

(This used to be ctdb commit eed3f4988290bbe317a7aaa6f61826676dd8365a)

ctdb/tests/takeover/ctdb_takeover.py

@@ -35,6 +35,10 @@ import itertools
 import socket
 import struct
 
+# For external algorithm
+import subprocess
+import re
+
 options = None
 
 def process_args(extra_options=[]):
@@ -52,6 +56,9 @@ def process_args(extra_options=[]):
     parser.add_option("-L", "--lcp2",
                       action="store_true", dest="lcp2", default=False,
                       help="use LCP2 IP rebalancing algorithm [default: %default]")
+    parser.add_option("-e", "--external",
+                      action="store_true", dest="external", default=False,
+                      help="use external test program to implement IP allocation algorithm [default: %default]")
     parser.add_option("-b", "--balance",
                       action="store_true", dest="balance", default=False,
                       help="show (im)balance information after each event")
@@ -685,10 +692,7 @@ class Cluster(object):
 
         return False
 
-
-    def ctdb_takeover_run(self):
-
-        self.events += 1
+    def ctdb_takeover_run_python(self):
 
         # Don't bother with the num_healthy stuff.  It is an
         # irrelevant detail.
@@ -752,6 +756,73 @@ class Cluster(object):
             else:
                 should_loop = self.basic_failback(retries_l)
 
+    def ctdb_takeover_run_external(self):
+
+        # Written while asleep...
+
+        # Convert the cluster state to something that be fed to
+        # ctdb_takeover_tests ctdb_takeover_run_core ...
+
+        in_lines = []
+        for ip in sorted(list(self.all_public_ips)):
+            allowed = []
+            assigned = -1
+            for (i, n) in enumerate(self.nodes):
+                if n.can_node_serve_ip(ip):
+                    allowed.append("%s" % i)
+                if ip in n.current_addresses:
+                    assigned = i
+            line = "%s\t%d\t%s" % (ip, assigned, ",".join(allowed))
+            in_lines.append(line)
+
+        nodestates = ",".join(["0" if n.healthy else "1" for n in self.nodes])
+
+        if options.lcp2:
+            os.environ["CTDB_LCP2"] = "yes"
+        if options.verbose > 1:
+            os.environ["CTDB_TEST_LOGLEVEL"] = "4"
+        elif options.verbose == 1:
+            os.environ["CTDB_TEST_LOGLEVEL"] = "3"
+        else:
+            os.environ["CTDB_TEST_LOGLEVEL"] = "0"
+
+        p = subprocess.Popen("../bin/ctdb_takeover_tests ctdb_takeover_run_core %s 2>&1" % nodestates,
+                             shell=True,
+                             stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+        p.stdin.write("\n".join(in_lines))
+        p.stdin.close()
+
+        # Flush all of the assigned IPs.
+        for n in self.nodes:
+            n.current_addresses = set()
+
+        # Uses the results to populate the current_addresses for each
+        # node.
+        for line in p.stdout.read().split("\n"):
+            # Some lines are debug, some are the final IP
+            # configuration.  Let's use a gross hack that assumes any
+            # line with 2 words is IP configuration.  That will do for
+            # now.
+            words = re.split("\s+", line)
+            if len(words) == 2:
+                # Add the IP as current for the specified node.
+                self.nodes[int(words[1])].current_addresses.add(words[0])
+            else:
+                 # First 3 words are log date/time, remove them...
+                 print " ".join(words[3:])
+
+        # Now fake up the LCP calculations.
+        for n in self.nodes:
+            n.set_imbalance()
+
+    def ctdb_takeover_run(self):
+
+        self.events += 1
+
+        if options.external:
+            return self.ctdb_takeover_run_external()
+        else:
+            return self.ctdb_takeover_run_python()
 
     def recover(self):
         verbose_begin("TAKEOVER")