Add the ability to use runqueue schedulers from the metadata

If you create a runqueue scheduler class in a python module, available in the
usual python search path, you can now make it available to bitbake via the
BB_SCHEDULERS variable, and the user can then select it as they select any
other scheduler.

Example usage:

    In a test.py I placed appropriately:

        import bb.runqueue

        class TestScheduler(bb.runqueue.RunQueueScheduler):
            name = "myscheduler"

    In local.conf, to make it available and select it:

        BB_SCHEDULERS = "test.TestScheduler"
        BB_SCHEDULER = "myscheduler"

(Bitbake rev: 4dd38d5cfb80f9bb72bc41a629c3320b38f7314d)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

1 files changed, 23 insertions, 7 deletions

diff --git a/bitbake/lib/bb/runqueue.py b/bitbake/lib/bb/runqueue.py
index 6d9f6dc8d..a1f79e9f0 100644
--- a/bitbake/lib/bb/runqueue.py
+++ b/bitbake/lib/bb/runqueue.py
@@ -177,6 +177,25 @@ class RunQueueData:
         self.stampwhitelist = bb.data.getVar("BB_STAMP_WHITELIST", cfgData, 1) or ""
         self.multi_provider_whitelist = (bb.data.getVar("MULTI_PROVIDER_WHITELIST", cfgData, 1) or "").split()
 
+        self.schedulers = set(obj for obj in globals().itervalues()
+                              if type(obj) is type and issubclass(obj, RunQueueScheduler))
+
+        user_schedulers = bb.data.getVar("BB_SCHEDULERS", cfgData, True)
+        if user_schedulers:
+            for sched in user_schedulers.split():
+                if not "." in sched:
+                    bb.note("Ignoring scheduler '%s' from BB_SCHEDULERS: not an import" % sched)
+                    continue
+
+                modname, name = sched.rsplit(".", 1)
+                try:
+                    module = __import__(modname, fromlist=(name,))
+                except ImportError, exc:
+                    logger.critical("Unable to import scheduler '%s' from '%s': %s" % (name, modname, exc))
+                    raise SystemExit(1)
+                else:
+                    self.schedulers.add(getattr(module, name))
+
         self.reset()
 
     def reset(self):
@@ -1183,17 +1202,14 @@ class RunQueueExecuteTasks(RunQueueExecute):
 
         event.fire(bb.event.StampUpdate(self.rqdata.target_pairs, self.rqdata.dataCache.stamp), self.cfgData)
 
-        schedulers = [obj for obj in globals().itervalues()
-                      if type(obj) is type and issubclass(obj, RunQueueScheduler)]
-        for scheduler in schedulers:
+        for scheduler in self.rqdata.schedulers:
             if self.scheduler == scheduler.name:
                 self.sched = scheduler(self, self.rqdata)
+                bb.msg.debug(1, bb.msg.domain.RunQueue, "Using runqueue scheduler '%s'" % scheduler.name)
                 break
         else:
-            bb.error("Invalid scheduler '%s', using default 'speed' scheduler" % self.scheduler)
-            bb.error("Available schedulers: %s" % ", ".join(obj.name for obj in schedulers))
-            self.sched = RunQueueSchedulerSpeed(self, self.rqdata)
-
+            bb.fatal("Invalid scheduler '%s'. Available schedulers: %s" %
+                     (self.scheduler, ", ".join(obj.name for obj in self.rqdata.schedulers)))
 
     def task_completeoutright(self, task):
         """