hpc garbage collector
diff --git a/planetstack/hpc_observer/steps/garbage_collector.py b/planetstack/hpc_observer/steps/garbage_collector.py
new file mode 100644
index 0000000..bf99da7
--- /dev/null
+++ b/planetstack/hpc_observer/steps/garbage_collector.py
@@ -0,0 +1,67 @@
+import os
+import sys
+import base64
+import traceback
+from collections import defaultdict
+from django.db.models import F, Q
+from planetstack.config import Config
+from util.logger import Logger, logging
+from observer.syncstep import SyncStep
+from hpc.models import ServiceProvider, ContentProvider, CDNPrefix, OriginServer
+from core.models import *
+
+# hpclibrary will be in steps/..
+parentdir = os.path.join(os.path.dirname(__file__),"..")
+sys.path.insert(0,parentdir)
+
+from hpclib import HpcLibrary
+
+logger = Logger(level=logging.INFO)
+
+class GarbageCollector(SyncStep, HpcLibrary):
+#    requested_interval = 86400
+    requested_interval = 0
+    provides=[]
+
+    def __init__(self, **args):
+        SyncStep.__init__(self, **args)
+        HpcLibrary.__init__(self)
+
+    def call(self, **args):
+        logger.info("running garbage collector")
+        try:
+            self.gc_originservers()
+            self.gc_cdnprefixes()
+            self.gc_contentproviders()
+            self.gc_serviceproviders()
+        except:
+            traceback.print_exc()
+
+    def gc_onev(self, ps_class, ps_idField, onev_className, onev_idField):
+        # get the CMI's objects
+        onev_objs = self.client.onev.ListAll(onev_className)
+
+        # get the data model's objects,
+        ps_objs = ps_class.objects.filter(enacted__isnull=False)
+        ps_ids = [str(getattr(x,ps_idField,None)) for x in ps_objs]
+
+        # for each onev object, if it's id does not exist in a data model
+        # object, then delete it.
+        for onev_obj in onev_objs:
+            onev_id = onev_obj[onev_idField]
+            if str(onev_id) not in ps_ids:
+                logger.info("garbage collecting %s %s" % (onev_className, str(onev_id)))
+                self.client.onev.Delete(onev_className, onev_id)
+
+    def gc_originservers(self):
+        self.gc_onev(OriginServer, "origin_server_id", "OriginServer", "origin_server_id")
+
+    def gc_cdnprefixes(self):
+        self.gc_onev(CDNPrefix, "cdn_prefix_id", "CDNPrefix", "cdn_prefix_id")
+
+    def gc_contentproviders(self):
+        self.gc_onev(ContentProvider, "content_provider_id", "ContentProvider", "content_provider_id")
+
+    def gc_serviceproviders(self):
+        self.gc_onev(ServiceProvider, "service_provider_id", "ServiceProvider", "service_provider_id")
+