Only calculate slave->build mapping once in json output.

third_party/buildbot_8_4p1/buildbot/status/web/status_json.py

Index: third_party/buildbot_8_4p1/buildbot/status/web/status_json.py
diff --git a/third_party/buildbot_8_4p1/buildbot/status/web/status_json.py b/third_party/buildbot_8_4p1/buildbot/status/web/status_json.py
index b656563257e3b0dbe89ca0e3fe26b330c1e7d99b..87a7f2da19fa470b1b7fd6ed605615b1b44ca78a 100644
--- a/third_party/buildbot_8_4p1/buildbot/status/web/status_json.py
+++ b/third_party/buildbot_8_4p1/buildbot/status/web/status_json.py
@@ -16,6 +16,7 @@
 
 """Simple JSON exporter."""
 
+import collections
 import datetime
 import os
 import re
@@ -414,12 +415,14 @@ class BuilderSlavesJsonResources(JsonResource):
     pageTitle = 'BuilderSlaves'
 
     def __init__(self, status, builder_status):
+        buildcache = collections.defaultdict(dict)

[M-A Ruel, 2013/04/06 01:23:46]

Why not create a single global instance? It'd be simpler and more efficient.

[Mike Stip (use stip instead), 2013/04/06 01:30:28]

Because this is per-request. It's only a cache while the JSON is being build up,
then it should be discarded.

         JsonResource.__init__(self, status)
         self.builder_status = builder_status
         for slave_name in self.builder_status.slavenames:
             self.putChild(slave_name,
                           SlaveJsonResource(status,
-                                            self.status.getSlave(slave_name)))
+                                            self.status.getSlave(slave_name),
+                                            buildcache=buildcache))
 
 
 class BuildJsonResource(JsonResource):
@@ -620,12 +623,18 @@ class SlaveJsonResource(JsonResource):
 """
     pageTitle = 'Slave'
 
-    def __init__(self, status, slave_status):
+    def __init__(self, status, slave_status, buildcache=None):
         JsonResource.__init__(self, status)
         self.slave_status = slave_status
         self.name = self.slave_status.getName()
         self.builders = None
 
+        # buildcache is used to cache build information across multiple
+        # invocations of SlaveJsonResource. It should be set to an empty
+        # collections.defaultdict(dict). Without it, each invocation will
+        # do a full build scan.
+        self.buildcache = buildcache or collections.defaultdict(dict)
+
     def getBuilders(self):
         if self.builders is None:
             # Figure out all the builders to which it's attached
@@ -635,10 +644,7 @@ class SlaveJsonResource(JsonResource):
                     self.builders.append(builderName)
         return self.builders
 
-    def asDict(self, request):
-        results = self.slave_status.asDict()
-        # Enhance it by adding more informations.
-        results['builders'] = {}
+    def mapSlavesToBuilds(self):

[Isaac (away), 2013/04/05 23:45:01]

delete this method and inline to line 662

[Mike Stip (use stip instead), 2013/04/06 01:30:28]

Done.

         for builderName in self.getBuilders():
             builds = []
             builder_status = self.status.getBuilder(builderName)
@@ -647,9 +653,19 @@ class SlaveJsonResource(JsonResource):
                 if not build_status or not build_status.isFinished():
                     # If not finished, it will appear in runningBuilds.
                     break
-                if build_status.getSlavename() == self.name:
-                    builds.append(build_status.getNumber())
-            results['builders'][builderName] = builds
+                slave = self.buildcache[build_status.getSlavename()]
+                slave.setdefault(builderName, []).append(

[M-A Ruel, 2013/04/06 01:23:46]

Note that it is effectively a memory leak, not a big one since it's just numbers
but still.

[Mike Stip (use stip instead), 2013/04/06 01:30:28]

buildcache gets thrown away after every request.

+                        build_status.getNumber())
+
+    def getSlaveBuildMap(self):
+        if not self.buildcache:
+            self.mapSlavesToBuilds()
+        return self.buildcache[self.name]
+
+    def asDict(self, request):
+        results = self.slave_status.asDict()
+        # Enhance it by adding more informations.
+        results['builders'] = self.getSlaveBuildMap()
         return results
 
 
@@ -659,11 +675,13 @@ class SlavesJsonResource(JsonResource):
     pageTitle = 'Slaves'
 
     def __init__(self, status):
+        buildcache = collections.defaultdict(dict)
         JsonResource.__init__(self, status)
         for slave_name in status.getSlaveNames():
             self.putChild(slave_name,
                           SlaveJsonResource(status,
-                                            status.getSlave(slave_name)))
+                                            status.getSlave(slave_name),
+                                            buildcache=buildcache))
 
 
 class SourceStampJsonResource(JsonResource):