Class and object dependencies, schedules

[plstackapi.git] / planetstack / observer / syncstep.py

diff --git a/planetstack/observer/syncstep.py b/planetstack/observer/syncstep.py
index b206106..f3eb4ba 100644 (file)
--- a/planetstack/observer/syncstep.py
+++ b/planetstack/observer/syncstep.py
@@ -2,6 +2,9 @@ import os
 import base64
 from planetstack.config import Config
 
+class FailedDependency(Exception):
+       pass
+
 class SyncStep:
        """ A PlanetStack Sync step. 
 
@@ -24,6 +27,7 @@ class SyncStep:
                                name -- Name of the step
                                provides -- PlanetStack models sync'd by this step
                """
+               dependencies = []
                try:
                        self.soft_deadline = int(self.get_prop('soft_deadline_seconds'))
                except:
@@ -33,9 +37,26 @@ class SyncStep:
 
        def fetch_pending(self):
                return Sliver.objects.filter(ip=None)
+       
+       def check_dependencies(self, obj):
+               for dep in dependencies:
+                       peer_object = getattr(obj, dep.name.lowercase())
+                       if (peer_object.pk==dep.pk):
+                               raise DependencyFailed
 
-       def call(self):
-               return True
+       def call(self, failed=failed_objects):
+               pending = self.fetch_pending()
+               failed = []
+               for o in pending:
+                       if (not self.depends_on(o, failed)):
+                               try:
+                                       check_dependencies(o) # Raises exception if failed                                      
+                                       self.sync_record(o)
+                                       o.enacted = datetime.now() # Is this the same timezone? XXX
+                                       o.save(update_fields=['enacted'])
+                               except:
+                                       failed.append(o)
+               return failed
 
        def __call__(self):
                return self.call()