From 91b8ac3f980f74ba0de610ce55f7444d12213f90 Mon Sep 17 00:00:00 2001
From: Sandy Walsh <sandy.walsh@rackspace.com>
Date: Wed, 11 May 2011 11:12:31 -0700
Subject: [PATCH] start of zone_aware_scheduler test

---
 nova/scheduler/api.py                  | 39 ++++++++++++++++++++++++++
 nova/scheduler/zone_aware_scheduler.py | 31 ++++++++++++--------
 2 files changed, 58 insertions(+), 12 deletions(-)

diff --git a/nova/scheduler/api.py b/nova/scheduler/api.py
index d8a0025e..55f8e0a6 100644
--- a/nova/scheduler/api.py
+++ b/nova/scheduler/api.py
@@ -111,6 +111,45 @@ def _process(func, zone):
     return func(nova, zone)
 
 
+def call_zone_method(context, method, errors_to_ignore=None, *args, **kwargs):
+    """Returns a list of (zone, call_result) objects."""
+    if not isinstance(errors_to_ignore, (list, tuple)):
+        # This will also handle the default None
+        errors_to_ignore = [errors_to_ignore]
+
+    pool = greenpool.GreenPool()
+    results = []
+    for zone in db.zone_get_all(context):
+        try:
+            nova = novaclient.OpenStack(zone.username, zone.password,
+                    zone.api_url)
+            nova.authenticate()
+        except novaclient.exceptions.BadRequest, e:
+            url = zone.api_url
+            LOG.warn(_("Failed request to zone; URL=%(url)s: %(e)s")
+                    % locals())
+            #TODO (dabo) - add logic for failure counts per zone,
+            # with escalation after a given number of failures.
+            continue
+        zone_method = getattr(nova.zones, method)
+
+        def _error_trap(*args, **kwargs):
+            try:
+                return zone_method(*args, **kwargs)
+            except Exception as e:
+                if type(e) in errors_to_ignore:
+                    return None
+                # TODO (dabo) - want to be able to re-raise here.
+                # Returning a string now; raising was causing issues.
+                # raise e
+                return "ERROR", "%s" % e
+
+        res = pool.spawn(_error_trap, *args, **kwargs)
+        results.append((zone, res))
+    pool.waitall()
+    return [(zone.id, res.wait()) for zone, res in results]
+
+
 def child_zone_helper(zone_list, func):
     """Fire off a command to each zone in the list.
     The return is [novaclient return objects] from each child zone.
diff --git a/nova/scheduler/zone_aware_scheduler.py b/nova/scheduler/zone_aware_scheduler.py
index b849e8de..b85cdfe6 100644
--- a/nova/scheduler/zone_aware_scheduler.py
+++ b/nova/scheduler/zone_aware_scheduler.py
@@ -24,11 +24,12 @@ import operator
 
 from nova import log as logging
 from nova.scheduler import api
+from nova.scheduler import driver
 
 LOG = logging.getLogger('nova.scheduler.zone_aware_scheduler')
 
 
-class ZoneAwareScheduler(object):
+class ZoneAwareScheduler(driver.Scheduler):
     """Base class for creating Zone Aware Schedulers."""
 
     def _call_zone_method(self, context, method, specs):
@@ -42,23 +43,29 @@ class ZoneAwareScheduler(object):
         anything about the children."""
         return self._schedule(context, "compute", *args, **kwargs)
 
-   def schedule(self, context, topic, *args, **kwargs):
+    def schedule(self, context, topic, *args, **kwargs):
         """The schedule() contract requires we return the one
         best-suited host for this request.
         """
         res = self._schedule(context, topic, *args, **kwargs)
+        # TODO(sirp): should this be a host object rather than a weight-dict?
         return res[0]
 
     def _schedule(self, context, topic, *args, **kwargs):
         """Returns a list of hosts that meet the required specs,
         ordered by their fitness.
         """
+
+        #TODO(sandy): extract these from args.
+        num_instances = 1
+        specs = {}
+
         # Filter local hosts based on requirements ...
-        host_list = self.filter_hosts()
+        host_list = self.filter_hosts(num_instances, specs)
 
         # then weigh the selected hosts.
         # weighted = [ { 'weight':#, 'name':host, ...}, ]
-        weighted = self.weight_hosts(host_list)
+        weighted = self.weigh_hosts(num_instances, specs, host_list)
 
         # Next, tack on the best weights from the child zones ...
         child_results = self._call_zone_method(context, "select",
@@ -77,12 +84,12 @@ class ZoneAwareScheduler(object):
         weighted.sort(key=operator.itemgetter('weight'))
         return weighted
 
-   def filter_hosts(self):
-       """Derived classes must override this method and return
-          a list of hosts in [?] format."""
-          raise NotImplemented()
+    def filter_hosts(self, num, specs):
+        """Derived classes must override this method and return
+           a list of hosts in [?] format."""
+        raise NotImplemented()
 
-   def weigh_hosts(self, hosts):
-       """Derived classes must override this method and return
-          a lists of hosts in [?] format."""
-          raise NotImplemented()
+    def weigh_hosts(self, num, specs, hosts):
+        """Derived classes must override this method and return
+           a lists of hosts in [?] format."""
+        raise NotImplemented()