Copy nodeset when making node requests

Nodesets are collections of nodes, but they, and the Node objects
they contain, have a dual role representing both the configuration
of a job and the actual nodes returned from nodepool.  So that
multiple jobs sharing the same nodeset configuration don't end up
sharing the same actual nodes, create a copy of a job's nodeset
for use in interacting with nodepool/zk.

Change-Id: I83f503ba22fc3f92b8c90b15ccfb6b07dc3c4709

zuul/model.py

@@ -353,9 +353,10 @@ class Node(object):
     def __init__(self, name, image):
         self.name = name
         self.image = image
+        self.id = None
 
     def __repr__(self):
-        return '<Node %s:%s>' % (self.name, self.image)
+        return '<Node %s %s:%s>' % (self.id, self.name, self.image)
 
 
 class NodeSet(object):
@@ -372,6 +373,12 @@ class NodeSet(object):
         self.name = name or ''
         self.nodes = OrderedDict()
 
+    def copy(self):
+        n = NodeSet(self.name)
+        for name, node in self.nodes.items():
+            n.addNode(Node(node.name, node.image))
+        return n
+
     def addNode(self, node):
         if node.name in self.nodes:
             raise Exception("Duplicate node in %s" % (self,))
@@ -399,6 +406,7 @@ class NodeRequest(object):
         self.state_time = time.time()
         self.stat = None
         self.uid = uuid4().hex
+        self.id = None
 
     @property
     def state(self):
@@ -413,7 +421,7 @@ class NodeRequest(object):
         self.state_time = time.time()
 
     def __repr__(self):
-        return '<NodeRequest %s>' % (self.nodeset,)
+        return '<NodeRequest %s %s>' % (self.id, self.nodeset)
 
     def toDict(self):
         d = {}

zuul/nodepool.py

@@ -23,7 +23,10 @@ class Nodepool(object):
         self.sched = scheduler
 
     def requestNodes(self, build_set, job):
-        req = NodeRequest(build_set, job, job.nodeset)
+        # Create a copy of the nodeset to represent the actual nodes
+        # returned by nodepool.
+        nodeset = job.nodeset.copy()
+        req = NodeRequest(build_set, job, nodeset)
         self.requests[req.uid] = req
         self.log.debug("Submitting node request: %s" % (req,))