API update

2003/12/28 17:02:52-06:00 (none)!desai
initial Generator class

(Logical change 1.7)


git-svn-id: https://svn.mcs.anl.gov/repos/bcfg/trunk/bcfg2@24 ce84e21b-d406-0410-9b95-82705330c041

1 files changed, 82 insertions, 8 deletions

diff --git a/src/Generator.py b/src/Generator.py
index ef7fa72e2..8c773548d 100644
--- a/src/Generator.py
+++ b/src/Generator.py
@@ -1,18 +1,31 @@
 #!/usr/bin/env python
+# $Id$
+
+from syslog import syslog, LOG_ERR
 
 class GeneratorError(Exception):
     pass
 
 class Generator(object):
-    '''This is a class that generators can be subclassed off of.'''
+    '''This is a class that generators can be subclassed from.
+    __name__, __version__, and __author__ must be set for the module
+    __build__ is a dictionary mapping filename to generator function
+    __requires__ is a set of external published data needed for operation'''
+    
     __name__ = None
-    __version__ = '$Id: $'
-    __datastore__ = '/tmp/data'
+    __version__ = None
+    __datastore__ = '/home/desai/data/b2'
     __build__ = {}
+    __requires__ = []
     
-    def __init__(self):
+    def __init__(self, container):
+        self.container=container
         self.data="%s/%s"%(self.__datastore__,self.__name__)
-        print "%s loaded"%(self.__name__)
+        self.PublishAll()
+
+    def CompleteSetup(self):
+        self.ReadAll()
+        print "%s loaded"%(self.__version__)
 
     def Cron(self):
         '''Cron defines periodic tasks to maintain data coherence'''
@@ -21,16 +34,24 @@ class Generator(object):
     def Build(self,filename,client):
         '''Build will construct a Config File object for client.'''
         if self.__build__.has_key(filename):
-            self.__build__[filename](filename,client)
+            return getattr(self,self.__build__[filename])(filename,client)
         else:
             raise GeneratorError, ("Key",filename)
 
     def Publish(self,key,value):
-        pass
+        self.container.Publish(self.__name__,key,value)
 
-    def Fetch(self,key):
+    def PublishAll(self):
         pass
 
+    def Read(self,key):
+        self.container.ReadValue(key)
+
+    def ReadAll(self):
+        self.external = {}
+        for field in self.__requires__:
+            self.external[field] = self.Read(field)
+
     def GetMetadata(self,client,field):
         '''GetMetadata returns current metadata file client. Field can be one of:
         image, tags, bundles'''
@@ -39,3 +60,56 @@ class Generator(object):
     def Notify(self,region):
         '''Generate change notification for region'''
         pass
+
+class PublishError(Exception):
+    pass
+
+class PublishedValue(object):
+    def __init__(self,owner,key,value):
+        self.owner=owner
+        self.key=key
+        self.value=value
+
+    def Update(self,owner,value):
+        if owner != self.owner:
+            raise PublishError, (self.key,owner)
+        self.value=value
+
+class GeneratorContainer(object):
+    def __init__(self):
+        self.pubspace={}
+        self.generators=[]
+        # we need to setup publish, read interface
+        # we need to inventory and setup generators
+        pass
+
+    def PublishValue(self,owner,key,value):
+        if not self.pubspace.has_key(key):
+            # This is a new entry
+            self.pubspace[key]=PublishedValue(owner,key,value)
+        else:
+            # This is an old entry. Update can fai
+            try:
+                self.pubspace[key].Update(owner,value)
+            except PublishError,e:
+                syslog(LOG_ERR, "Publish conflict for %s. Owner %s, Modifier %s"%(key,self.pubspace[key].owner,owner))
+
+    def ReadValue(self,key):
+        if self.pubspace.has_key(key):
+            return self.pubspace[key].value
+        raise KeyError,key
+
+    def LoadGenerators(self,genlist):
+        for generator in genlist:
+            self.generators.append(generator(self))
+        for generator in self.generators:
+            generator.CompleteSetup()
+        self.handles={}
+        for g in self.generators:
+            for f in g.__build__.keys():
+                self.handles[f]=g
+
+    def GetConfigFile(self,filename,client):
+        if self.handles.has_key(filename):
+            return self.handles[filename].Build(filename,client)
+        raise KeyError, filename