Initial commit.

16 files changed, 1537 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000..84dbe1d0d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,6 @@
+build
+dist
+zuul.egg-info
+MANIFEST
+.tox
+
diff --git a/.gitreview b/.gitreview
new file mode 100644
index 000000000..cf39bc601
--- /dev/null
+++ b/.gitreview
@@ -0,0 +1,4 @@
+[gerrit]
+host=review.openstack.org
+port=29418
+project=openstack-ci/zuul.git
diff --git a/AUTHORS b/AUTHORS
new file mode 100644
index 000000000..1fd7b21b8
--- /dev/null
+++ b/AUTHORS
@@ -0,0 +1 @@
+James E. Blair <jeblair@hp.com>
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 000000000..75b52484e
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,202 @@
+

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diff --git a/README b/README
new file mode 100644
index 000000000..52383b50f
--- /dev/null
+++ b/README
@@ -0,0 +1 @@
+This is a trunk gating system developed for the OpenStack Project.
diff --git a/setup.py b/setup.py
new file mode 100644
index 000000000..8456cc4bb
--- /dev/null
+++ b/setup.py
@@ -0,0 +1,31 @@
+#!/usr/bin/env python
+# Copyright 2012 Hewlett-Packard Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from setuptools import find_packages
+from setuptools.command.sdist import sdist
+from setuptools import setup
+import subprocess
+
+setup(name='zuul',
+      version='1.0',
+      description="Trunk gating system",
+      license='Apache License (2.0)',
+      author='Hewlett-Packard Development Company, L.P.',
+      author_email='openstack@lists.launchpad.net',
+      url='http://launchpad.net/zuul',
+      scripts=['zuul-server'],
+      include_package_data=True,
+      zip_safe=False,
+      )
diff --git a/zuul-server b/zuul-server
new file mode 100755
index 000000000..e3e192671
--- /dev/null
+++ b/zuul-server
@@ -0,0 +1,53 @@
+import argparse
+import ConfigParser
+import os
+
+import zuul.scheduler
+import zuul.launcher.jenkins
+import zuul.trigger.gerrit
+
+import logging.config
+
+def parse_arguments():
+    parser = argparse.ArgumentParser(description='Project gating system.')
+    parser.add_argument('-c', dest='config',
+                        help='specify the config file')
+    return parser.parse_args()
+
+def read_config(args):
+    config=ConfigParser.ConfigParser()
+    if args.config:
+        locations = [args.config]
+    else:
+        locations = ['/etc/zuul/zuul.conf',
+                     '~/zuul.conf']
+    for fp in locations:
+        if os.path.exists(os.path.expanduser(fp)):
+            config.read(fp)
+            return config
+    raise Exception("Unable to locate config file in %s" % locations)
+
+def setup_logging(config):
+    if config.has_option('zuul', 'log_config'):
+        fp = os.path.expanduser(config.get('zuul', 'log_config'))
+        if not os.path.exists(fp):
+            raise Exception("Unable to read logging config file at %s" % fp)
+        logging.config.fileConfig(fp)
+    else:
+        logging.basicConfig(level=logging.DEBUG)
+
+def main(config):
+    sched = zuul.scheduler.Scheduler(config)
+
+    jenkins = zuul.launcher.jenkins.Jenkins(config, sched)
+    gerrit = zuul.trigger.gerrit.Gerrit(config, sched)
+
+    sched.setLauncher(jenkins)
+    sched.setTrigger(gerrit)
+    sched.run()
+
+if __name__ == '__main__':
+    args = parse_arguments()
+    config = read_config(args)
+    setup_logging(config)
+    main(config)
diff --git a/zuul/__init__.py b/zuul/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/zuul/__init__.py
diff --git a/zuul/launcher/__init__.py b/zuul/launcher/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/zuul/launcher/__init__.py
diff --git a/zuul/launcher/jenkins.py b/zuul/launcher/jenkins.py
new file mode 100644
index 000000000..cd9e19d55
--- /dev/null
+++ b/zuul/launcher/jenkins.py
@@ -0,0 +1,217 @@
+# Copyright 2012 Hewlett-Packard Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+# So we can name this module "jenkins" and still load the "jenkins"
+# system module
+from __future__ import absolute_import
+
+import threading
+from webob import Request
+from paste import httpserver
+from uuid import uuid1
+import jenkins
+import json
+import urllib2  # for extending jenkins lib
+import logging
+import pprint
+
+from zuul.model import Build
+
+class JenkinsCallback(threading.Thread):
+    log = logging.getLogger("zuul.JenkinsCallback")
+
+    def __init__(self, jenkins):
+        threading.Thread.__init__(self)
+        self.jenkins = jenkins
+
+    def run(self):
+        httpserver.serve(self.app, host='0.0.0.0', port='8080')
+
+    def app(self, environ, start_response):
+        request = Request(environ)
+        if request.path == '/jenkins_endpoint':
+            self.jenkins_endpoint(request)
+        start_response('200 OK', [('content-type', 'text/html')])
+        return ['Zuul good.']
+
+    def jenkins_endpoint(self, request):
+        data = json.loads(request.body)
+        if data:
+            self.log.debug("Received data from Jenkins: \n%s" % (
+                    pprint.pformat(data)))
+            build = data.get('build')
+            if build:
+                phase = build.get('phase')
+                status = build.get('status')
+                url = build.get('full_url')
+                number = build.get('number')
+                params = build.get('parameters')
+                if params:
+                    uuid = params.get('UUID')
+                    if (status and url and uuid and phase
+                        and phase == 'COMPLETED'):
+                        self.jenkins.onBuildCompleted(uuid, status, url, number)
+                    if (phase and phase == 'STARTED'):
+                        self.jenkins.onBuildStarted(uuid, url, number)
+
+
+STOP_BUILD = 'job/%(name)s/%(number)s/stop'
+CANCEL_QUEUE = 'queue/item/%(number)s/cancelQueue'
+BUILD_INFO = 'job/%(name)s/%(number)s/api/json?depth=0'
+
+class ExtendedJenkins(jenkins.Jenkins):
+    def jenkins_open(self, req):
+        '''
+        Utility routine for opening an HTTP request to a Jenkins server. 
+        '''
+        try:
+            if self.auth:
+                req.add_header('Authorization', self.auth)
+            return urllib2.urlopen(req).read()
+        except urllib2.HTTPError, e:
+            print e.msg
+            print e.fp.read()
+            raise
+
+    def stop_build(self, name, number):
+        '''
+        Stop a running Jenkins build.
+
+        @param name: Name of Jenkins job
+        @type  name: str
+        @param number: Jenkins build number for the job
+        @type  number: int
+        '''
+        self.jenkins_open(urllib2.Request(self.server + STOP_BUILD%locals()))
+
+    def cancel_queue(self, number):
+        '''
+        Cancel a queued build.
+
+        @param number: Jenkins queue number for the build
+        @type  number: int
+        '''
+        # Jenkins returns a 302 from this URL, unless Referer is not set,
+        # then you get a 404.
+        self.jenkins_open(urllib2.Request(self.server + CANCEL_QUEUE%locals(),
+                                          headers={'Referer': self.server}))
+
+
+    def get_build_info(self, name, number):
+        '''
+        Get information for a build.
+
+        @param name: Name of Jenkins job
+        @type  name: str
+        @param number: Jenkins build number for the job
+        @type  number: int
+        @return: dictionary
+        '''
+        return json.loads(self.jenkins_open(urllib2.Request(self.server + BUILD_INFO%locals())))
+
+class Jenkins(object):
+    log = logging.getLogger("zuul.Jenkins")
+
+    def __init__(self, config, sched):
+        self.sched = sched
+        self.builds = {}
+        server = config.get('jenkins', 'server')
+        user = config.get('jenkins', 'user')
+        apikey = config.get('jenkins', 'apikey')
+        self.jenkins = ExtendedJenkins(server, user, apikey)
+        self.callback_thread = JenkinsCallback(self)
+        self.callback_thread.start()
+    
+    def launch(self, job, change, dependent_changes = []):
+        self.log.info("Launch job %s for change %s with dependent changes %s" % (
+                job, change, dependent_changes))
+        uuid = str(uuid1())
+        params = dict(UUID=uuid)
+        build = Build(job, uuid)
+        self.builds[uuid] = build
+        # We can get the started notification on another thread before this is done
+        # so we add the build even before we trigger the job on Jenkins.  We should
+        # be careful to clean it up if it doesn't actually kick off.
+        try:
+            self.jenkins.build_job(job.name, parameters=params)
+        except:
+            self.log.exception("Exception launching build %s for job %s for change %s:" % (
+                    build, job, change))
+            # Whoops.  Remove that build we added.
+            del self.builds[uuid]
+            raise
+        return build
+
+    def cancel(self, build):
+        self.log.info("Cancel build %s for job %s" % (build, build.job))
+        if build.number:
+            self.log.debug("Build %s has already started" % build)
+            self.jenkins.stop_build(build.job.name, build.number)
+            self.log.debug("Canceled running build %s" % build)
+            return
+        else:
+            self.log.debug("Build %s has not started yet" % build)
+
+        self.log.debug("Looking for build %s in queue" % build)
+        for item in self.jenkins.get_queue_info():
+            if not item.has_key('actions'):
+                continue
+            for action in item['actions']:
+                if not action.has_key('parameters'):
+                    continue
+                parameters = action['parameters']
+                for param in parameters:
+                    if (param['name'] == 'UUID' and build.uuid == param['value']):
+                        self.log.debug("Found queue item %s for build %s" % (
+                                item['id'], build))
+                        try:
+                            self.jenkins.cancel_queue(item['id'])
+                            self.log.debug("Canceled queue item %s for build %s" % (
+                                    item['id'], build))
+                            return
+                        except:
+                            self.log.exception("Exception canceling queue item %s for build %s" % (
+                                    item['id'], build))
+
+        self.log.debug("Still unable to find build %s to cancel" % build)
+        if build.number:
+            self.log.debug("Build %s has just started" % build)
+            self.jenkins.stop_build(build.job.name, build.number)
+            self.log.debug("Canceled just running build %s" % build)
+        else:
+            self.log.error("Build %s has not started but was not found in queue" % build)
+    
+    def onBuildCompleted(self, uuid, status, url, number):
+        self.log.info("Build %s #%s complete, status %s" % (
+                uuid, number, status))
+        build = self.builds.get(uuid)
+        if build:
+            self.log.debug("Found build %s" % build)
+            del self.builds[uuid]
+            build.result = status
+            build.url = url
+            build.number = number
+            self.sched.onBuildCompleted(build)
+        else:
+            self.log.error("Unable to find build %s" % uuid)
+
+    def onBuildStarted(self, uuid, url, number):
+        self.log.info("Build %s #%s started, url: %s" % (uuid, number, url))
+        build = self.builds.get(uuid)
+        if build:
+            self.log.debug("Found build %s" % build)
+            build.url = url
+            build.number = number
+        else:
+            self.log.error("Unable to find build %s" % uuid)
diff --git a/zuul/lib/__init__.py b/zuul/lib/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/zuul/lib/__init__.py
diff --git a/zuul/lib/gerrit.py b/zuul/lib/gerrit.py
new file mode 100644
index 000000000..9c72d4436
--- /dev/null
+++ b/zuul/lib/gerrit.py
@@ -0,0 +1,171 @@
+# Copyright 2012 Hewlett-Packard Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import threading
+import select
+import json
+import time
+import subprocess
+import Queue
+import paramiko
+import logging
+import pprint
+
+# TODO: switch this to paramiko?
+
+class GerritWatcher(threading.Thread):
+    log = logging.getLogger("gerrit.GerritWatcher")
+
+    def __init__(self, gerrit, username, server, port=29418, keyfile=None):
+        threading.Thread.__init__(self)
+        self.username = username
+        self.keyfile = keyfile
+        self.server = server
+        self.port = port
+        self.proc = None
+        self.poll = select.poll()
+        self.gerrit = gerrit
+
+    def _open(self):
+        self.log.debug("Opening ssh connection to %s" % self.server)
+        cmd = ['/usr/bin/ssh', '-p', str(self.port)]
+        if self.keyfile:
+            cmd += ['-i', self.keyfile]
+        cmd += ['-l', self.username, self.server,
+                'gerrit', 'stream-events']
+        self.proc = subprocess.Popen(cmd,
+                                     bufsize=1, 
+                                     stdin=None,
+                                     stdout=subprocess.PIPE,
+                                     stderr=None,
+                                     )
+        self.poll.register(self.proc.stdout)
+
+    def _close(self):
+        self.log.debug("Closing ssh connection")
+        try:
+            self.poll.unregister(self.proc.stdout)
+        except:
+            pass
+        try:
+            self.proc.kill()
+        except:
+            pass
+        self.proc = None
+
+    def _read(self):
+        l = self.proc.stdout.readline()
+        data = json.loads(l)
+        self.log.debug("Received data from Gerrit event stream: \n%s" % pprint.pformat(data))
+        self.gerrit.addEvent(data)
+
+    def _listen(self):
+        while True:
+            ret = self.poll.poll()
+            for (fd, event) in ret:
+                if fd == self.proc.stdout.fileno():
+                    if event == select.POLLIN:
+                        self._read()
+                    else:
+                        raise Exception("event on ssh connection")
+        
+    def _run(self):
+        try:
+            if not self.proc:
+                self._open()
+            self._listen()
+        except:
+            self.log.exception("Exception on ssh event stream:")
+            self._close()
+            time.sleep(5)
+
+    def run(self):
+        while True:
+            self._run()
+
+class Gerrit(object):
+    log = logging.getLogger("gerrit.Gerrit")
+
+    def __init__(self, hostname, username, keyfile=None):
+        self.username = username
+        self.hostname = hostname
+        self.keyfile = keyfile
+        self.watcher_thread = None
+        self.event_queue = None
+
+    def startWatching(self):
+        self.event_queue = Queue.Queue()
+        self.watcher_thread = GerritWatcher(
+            self,
+            self.username,
+            self.hostname,
+            keyfile=self.keyfile)
+        self.watcher_thread.start()
+
+    def addEvent(self, data):
+        return self.event_queue.put(data)
+
+    def getEvent(self):
+        return self.event_queue.get()
+
+    def review(self, project, change, message, action={}):
+        cmd = 'gerrit review --project %s --message "%s"' % (
+            project, message)
+        for k,v in action.items():
+            if v == True:
+                cmd += ' --%s' % k
+            else:
+                cmd += ' --%s %s' % (k, v)
+        cmd += ' %s' % change
+        out, err = self._ssh(cmd)
+        return err
+
+    def query(self, change):
+        cmd = 'gerrit query --format json %s"' % (
+            change)
+        out, err = self._ssh(cmd)
+        if not out:
+            return False
+        lines = out.split('\n')
+        if not lines:
+            return False
+        data = json.loads(lines[0])
+        if not data:
+            return False
+        self.log.debug("Received data from Gerrit query: \n%s" % (
+                pprint.pformat(data)))
+        return data
+
+    def _ssh(self, command):
+        client = paramiko.SSHClient()
+        client.load_system_host_keys()
+        client.set_missing_host_key_policy(paramiko.WarningPolicy())
+        client.connect(self.hostname, 
+                       username=self.username,
+                       port=29418)
+
+        self.log.debug("SSH command:\n%s" % command)
+        stdin, stdout, stderr = client.exec_command(command)
+
+        out = stdout.read()
+        self.log.debug("SSH received stdout:\n%s" % out)
+
+        ret = stdout.channel.recv_exit_status()
+        self.log.debug("SSH exit status: %s" % ret)
+
+        err = stderr.read()
+        self.log.debug("SSH received stderr:\n%s" % err)
+        if ret:
+            raise Exception("Gerrit error executing %s" % command)
+        return (out, err)
diff --git a/zuul/model.py b/zuul/model.py
new file mode 100644
index 000000000..ac64761d1
--- /dev/null
+++ b/zuul/model.py
@@ -0,0 +1,323 @@
+# Copyright 2012 Hewlett-Packard Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import re
+
+class ChangeQueue(object):
+    def __init__(self, queue_name):
+        self.name = ''
+        self.queue_name = queue_name
+        self.projects = []
+        self._jobs = set()
+        self.queue = []
+
+    def __str__(self):
+        return '<ChangeQueue %s: %s>' % (self.queue_name, self.name)
+
+    def getJobs(self):
+        return self._jobs
+
+    def addProject(self, project):
+        if project not in self.projects:
+            self.projects.append(project)
+            names = [x.name for x in self.projects]
+            names.sort()
+            self.name = ', '.join(names)
+            self._jobs |= set(project.getJobs(self.queue_name))
+
+    def enqueueChange(self, change):
+        if self.queue:
+            self.queue[-1].change_behind = change
+            change.change_ahead = self.queue[-1]
+        self.queue.append(change)
+        change.queue = self
+
+    def dequeueChange(self, change):
+        if change in self.queue:
+            self.queue.remove(change)
+
+    def mergeChangeQueue(self, other):
+        for project in other.projects:
+            self.addProject(project)
+
+class Job(object):
+    def __init__(self, name):
+        self.name = name
+        self.failure_message = None
+        self.success_message = None
+        self.event_filters = []
+
+    def __str__(self):
+        return self.name
+
+    def __repr__(self):
+        return '<Job %s>' % (self.name)
+
+class Build(object):
+    def __init__(self, job, uuid):
+        self.job = job
+        self.uuid = uuid
+        self.status = None
+        self.url = None
+        self.number = None
+
+    def __repr__(self):
+        return '<Build %s of %s>' % (self.uuid, self.job.name)
+
+class JobTree(object):
+    """ A JobTree represents an instance of one Job, and holds JobTrees
+    whose jobs should be run if that Job succeeds.  A root node of a
+    JobTree will have no associated Job. """
+
+    def __init__(self, job):
+        self.job = job
+        self.job_trees = []
+
+    def addJob(self, job):
+        if job not in [x.job for x in self.job_trees]:
+            t = JobTree(job)
+            self.job_trees.append(t)
+            return t
+
+    def getJobs(self):
+        jobs = []
+        for x in self.job_trees:
+            jobs.append(x.job)
+            jobs.extend(x.getJobs())
+        return jobs
+
+    def getJobTreeForJob(self, job):
+        if self.job == job:
+            return self
+        for tree in self.job_trees:
+            ret = tree.getJobTreeForJob(job)
+            if ret:
+                return ret
+        return None
+
+class Project(object):
+    def __init__(self, name):
+        self.name = name
+        self.job_trees = {}  # Queue -> JobTree
+
+    def __str__(self):
+        return self.name
+
+    def __repr__(self):
+        return '<Project %s>' % (self.name)
+
+    def addQueue(self, name):
+        self.job_trees[name] = JobTree(None)
+        return self.job_trees[name]
+
+    def hasQueue(self, name):
+        if self.job_trees.has_key(name):
+            return True
+        return False
+
+    def getJobTreeForQueue(self, name):
+        return self.job_trees.get(name, None)
+
+    def getJobs(self, queue_name):
+        tree = self.getJobTreeForQueue(queue_name)
+        if not tree:
+            return []
+        return tree.getJobs()
+
+class Change(object):
+    def __init__(self, queue_name, project, number, patchset):
+        self.queue_name = queue_name
+        self.project = project
+        self.number = number
+        self.patchset = patchset
+        self.jobs = {}
+        self.job_urls = {}
+        self.change_ahead = None
+        self.change_behind = None
+        self.running_builds = []
+
+    def __str__(self):
+        return '<Change 0x%x %s,%s>' % (id(self), self.number, self.patchset)
+
+    def formatStatus(self, indent=0):
+        indent_str = ' '*indent
+        ret = ''
+        ret += '%sProject %s change %s,%s\n' % (indent_str,
+                                              self.project.name,
+                                              self.number, 
+                                              self.patchset)
+        for job in self.project.getJobs(self.queue_name):
+            result = self.jobs.get(job.name)
+            ret += '%s  %s: %s\n' % (indent_str, job.name, result)
+        if self.change_ahead:
+            ret += '%sWaiting on:\n' % (indent_str)
+            ret += self.change_ahead.formatStatus(indent+2)
+        return ret
+
+    def formatReport(self):
+        ret = ''
+        if self.didAllJobsSucceed():
+            ret += 'Build successful\n\n'
+        else:
+            ret += 'Build failed\n\n'
+        
+        for job in self.project.getJobs(self.queue_name):
+            result = self.jobs.get(job.name)
+            url = self.job_urls.get(job.name, job.name)
+            ret += '- %s : %s\n' % (url, result)
+        return ret
+
+    def resetAllBuilds(self):
+        self.jobs = {}
+        self.job_urls = {}
+        self.running_builds = []
+
+    def addBuild(self, build):
+        self.running_builds.append(build)
+
+    def setResult(self, build):
+        self.running_builds.remove(build)
+        self.jobs[build.job.name] = build.result
+        self.job_urls[build.job.name] = build.url
+        if build.result != 'SUCCESS':
+            # Get a JobTree from a Job so we can find only its dependent jobs
+            root = self.project.getJobTreeForQueue(self.queue_name)
+            tree = root.getJobTreeForJob(build.job)
+            for job in tree.getJobs():
+                self.jobs[job.name] = 'SKIPPED'
+
+    def _findJobsToRun(self, job_trees):
+        torun = []
+        for tree in job_trees:
+            job = tree.job
+            if job:
+                result = self.jobs.get(job.name, None)
+            else:
+                # This is a null job tree, run all of its jobs
+                result = 'SUCCESS'
+            if not result:
+                if job not in [b.job for b in self.running_builds]:
+                    torun.append(job)
+            elif result == 'SUCCESS':
+                torun.extend(self._findJobsToRun(tree.job_trees))
+        return torun
+
+    def findJobsToRun(self):
+        tree = self.project.getJobTreeForQueue(self.queue_name)
+        return self._findJobsToRun(tree.job_trees)
+
+    def areAllJobsComplete(self):
+        tree = self.project.getJobTreeForQueue(self.queue_name)
+        for job in tree.getJobs():
+            if not self.jobs.has_key(job.name):
+                return False
+        return True
+
+    def didAllJobsSucceed(self):
+        for result in self.jobs.values():
+            if result != 'SUCCESS':
+                return False
+        return True
+
+    def delete(self):
+        if self.change_behind:
+            self.change_behind.change_ahead = None
+
+class TriggerEvent(object):
+    def __init__(self):
+        self.data = None
+        self.type = None
+        self.project_name = None
+        self.change_number = None
+        self.patch_number = None
+        self.approvals = []
+        self.branch = None
+        self.ref = None
+
+    def __str__(self):
+        ret = '<TriggerEvent %s %s' % (self.type, self.project_name)
+        
+        if self.branch:
+            ret += " %s" % self.branch
+        if self.change_number:
+            ret += " %s,%s" % (self.change_number, self.patch_number)
+        if self.approvals:
+            ret += ' '+', '.join(['%s:%s' % (a['type'], a['value']) for a in self.approvals])
+        ret += '>'
+
+        return ret
+
+class EventFilter(object):
+    def __init__(self, types=[], branches=[], refs=[], approvals=[]):
+        self._types = types
+        self._branches = branches
+        self._refs = refs
+        self.types = [re.compile(x) for x in types]
+        self.branches = [re.compile(x) for x in branches]
+        self.refs = [re.compile(x) for x in refs]
+        self.approvals = approvals
+
+    def __str__(self):
+        ret = '<EventFilter'
+        
+        if self._types:
+            ret += ' types: %s' % ', '.join(self._types)
+        if self._branches:
+            ret += ' branches: %s' % ', '.join(self._branches)
+        if self._refs:
+            ret += ' refs: %s' % ', '.join(self._refs)
+        if self.approvals:
+            ret += ' approvals: %s' % ', '.join(['%s:%s' % a for a in self.approvals.items()])
+        ret += '>'
+
+        return ret
+
+    def matches(self, event):
+        def normalizeCategory(name):
+            name = name.lower()
+            return re.sub(' ', '-', name)
+
+        # event types are ORed
+        matches_type = False
+        for etype in self.types:
+            if etype.match(event.type):
+                matches_type = True
+        if self.types and not matches_type:
+            return False
+
+        # branches are ORed
+        matches_branch = False
+        for branch in self.branches:
+            if branch.match(event.branch):
+                matches_branch = True
+        if self.branches and not matches_branch:
+            return False
+
+        # refs are ORed
+        matches_ref = False
+        for ref in self.refs:
+            if ref.match(event.ref):
+                matches_ref = True
+        if self.refs and not matches_ref:
+            return False
+
+        # approvals are ANDed
+        for category, value in self.approvals.items():
+            matches_approval = False
+            for eapproval in event.approvals:
+                if (normalizeCategory(eapproval['description']) == category and
+                    int(eapproval['value']) == int(value)):
+                    matches_approval = True
+            if not matches_approval: return False
+        return True
diff --git a/zuul/scheduler.py b/zuul/scheduler.py
new file mode 100644
index 000000000..c6570c292
--- /dev/null
+++ b/zuul/scheduler.py
@@ -0,0 +1,436 @@
+# Copyright 2012 Hewlett-Packard Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import os
+import Queue
+import threading
+import logging
+import yaml
+
+
+from model import Job, Change, Project, ChangeQueue, EventFilter
+
+class Scheduler(object):
+    log = logging.getLogger("zuul.Scheduler")
+
+    def __init__(self, config):
+        self.wake_event = threading.Event()
+        self.queue_managers = {}
+        self.jobs = {}
+        self.projects = {}
+        self.launcher = None
+        self.trigger = None
+
+        self.trigger_event_queue = Queue.Queue()
+        self.result_event_queue = Queue.Queue()
+
+        self._parseConfig(config.get('zuul', 'layout_config'))
+
+    def _parseConfig(self, fp):
+        def toList(item):
+            if not item: return []
+            if type(item) == type([]):
+                return item
+            return [item]
+
+        if fp:
+            fp = os.path.expanduser(fp)
+            if not os.path.exists(fp):
+                raise Exception("Unable to read layout config file at %s" % fp)
+        fp = open(fp)
+        data = yaml.load(fp)
+        import pprint
+        pprint.pprint(data)
+        
+        for config_queue in data['queue']:
+            manager = globals()[config_queue['manager']](self, config_queue['name'])
+            self.queue_managers[config_queue['name']] = manager
+            manager.success_action = config_queue.get('success')
+            manager.failure_action = config_queue.get('failure')
+            for trigger in toList(config_queue['trigger']):
+                approvals = {}
+                for approval_dict in toList(trigger.get('approval')):
+                    for k, v in approval_dict.items():
+                        approvals[k]=v
+                f = EventFilter(types=toList(trigger['event']),
+                                branches=toList(trigger.get('branch')),
+                                refs=toList(trigger.get('ref')),
+                                approvals=approvals)
+                manager.event_filters.append(f)
+
+        for config_job in data['jobs']:
+            job = self.getJob(config_job['name'])
+            job.failure_message = config_job.get('failure-message', None)
+            job.success_message = config_job.get('success-message', None)
+            silent = config_job.get('silent', None)
+            if silent:
+                job.silent = True
+            branches = toList(config_job.get('branch'))
+            if branches:
+                f = EventFilter(branches=branches)
+                job.event_filters.append(f)
+
+        def add_jobs(job_tree, config_jobs):
+            for job in config_jobs:
+                if isinstance(job, list):
+                    for x in job:
+                        add_jobs(job_tree, x)
+                if isinstance(job, dict):
+                    for parent, children in job.items():
+                        parent_tree = job_tree.addJob(self.getJob(parent))
+                        add_jobs(parent_tree, children)
+                if isinstance(job, str):
+                    job_tree.addJob(self.getJob(job))
+
+        for config_project in data['projects']:
+            project = Project(config_project['name'])
+            self.projects[config_project['name']] = project
+            for qname in self.queue_managers.keys():
+                if config_project.has_key(qname):
+                    print project, qname
+                    job_tree = project.addQueue(qname)
+                    config_jobs = config_project[qname]
+                    add_jobs(job_tree, config_jobs)
+            
+
+        # TODO(jeblair): check that we don't end up with jobs like
+        # "foo - bar" because a ':' is missing in the yaml for a dependent job
+        for manager in self.queue_managers.values():
+            manager._postConfig()
+
+    def getJob(self, name):
+        if self.jobs.has_key(name):
+            return self.jobs[name]
+        job = Job(name)
+        self.jobs[name] = job
+        return job
+
+    def setLauncher(self, launcher):
+        self.launcher = launcher
+
+    def setTrigger(self, trigger):
+        self.trigger = trigger
+
+    def addEvent(self, event):
+        self.log.debug("Adding trigger event: %s" % event)
+        self.trigger_event_queue.put(event)
+        self.wake_event.set()
+
+    def onBuildCompleted(self, build):
+        self.log.debug("Adding result event for build: %s" % build)
+        self.result_event_queue.put(build)
+        self.wake_event.set()
+
+    def run(self):
+        while True:
+            self.log.debug("Run handler sleeping")
+            self.wake_event.wait()
+            self.wake_event.clear()
+            self.log.debug("Run handler awake")
+            try:
+                if not self.trigger_event_queue.empty():
+                    self.process_event_queue()
+                if not self.result_event_queue.empty():
+                    self.process_result_queue()
+            except:
+                self.log.exception("Exception in run handler:")
+
+    def process_event_queue(self):
+        self.log.debug("Fetching trigger event")
+        event = self.trigger_event_queue.get()
+        self.log.debug("Processing trigger event %s" % event)
+        project = self.projects.get(event.project_name)
+        if not project:
+            self.log.warning("Project %s not found" % event.project_name)
+            return
+
+        for manager in self.queue_managers.values():
+            if not manager.eventMatches(event):
+                self.log.debug("Event %s ignored by %s" % (event, manager))
+                continue
+            if event.change_number:
+                change = Change(manager.name, project,
+                                event.change_number, event.patch_number)
+                self.log.info("Adding %s, %s to to %s" % (
+                        project, change, manager))
+                manager.addChange(change)
+            
+    def process_result_queue(self):
+        self.log.debug("Fetching result event")
+        build = self.result_event_queue.get()
+        self.log.debug("Processing result event %s" % build)
+        for manager in self.queue_managers.values():
+            if manager.onBuildCompleted(build):
+                return
+
+class BaseQueueManager(object):
+    log = logging.getLogger("zuul.BaseQueueManager")
+
+    def __init__(self, sched, name):
+        self.sched = sched
+        self.name = name
+        self.building_jobs = {}
+        self.event_filters = []
+        self.success_action = {}
+        self.failure_action = {}
+
+    def __str__(self):
+        return "<%s %s>" % (self.__class__.__name__, self.name)
+
+    def _postConfig(self):
+        self.log.info("Configured Queue Manager %s" % self.name)
+        self.log.info("  Events:")
+        for e in self.event_filters:
+            self.log.info("    %s" % e)
+        self.log.info("  Projects:")
+        def log_jobs(tree, indent=0):
+            istr = '    '+' '*indent
+            if tree.job:
+                efilters = ''
+                for e in tree.job.event_filters:
+                    efilters += str(e)
+                if efilters:
+                    efilters = ' '+efilters
+                self.log.info("%s%s%s" % (istr, repr(tree.job), efilters))
+            for x in tree.job_trees:
+                log_jobs(x, indent+2)
+        for p in self.sched.projects.values():
+            if p.hasQueue(self.name):
+                self.log.info("    %s" % p)
+                log_jobs(p.getJobTreeForQueue(self.name))
+        if self.success_action:
+            self.log.info("  On success:")
+            self.log.info("    %s" % self.success_action)
+        if self.failure_action:
+            self.log.info("  On failure:")
+            self.log.info("    %s" % self.failure_action)
+
+
+    def eventMatches(self, event):
+        for ef in self.event_filters:
+            print ef
+            if ef.matches(event):
+                return True
+        return False
+
+
+    def addChange(self, change):
+        self.log.debug("Adding change %s" % change)
+        self.launchJobs(change)
+
+    def launchJobs(self, change):
+        self.log.debug("Launching jobs for change %s" % change)
+        for job in change.findJobsToRun():
+            self.log.debug("Found job %s for change %s" % (job, change))
+            try:
+                build = self.sched.launcher.launch(job, change)
+                self.building_jobs[build] = change
+                self.log.debug("Adding build %s of job %s to change %s" % (
+                        build, job, change))
+                change.addBuild(build)
+            except:
+                self.log.exception("Exception while launching job %s for change %s:" % (
+                        job, change))
+
+    def onBuildCompleted(self, build):
+        self.log.debug("Build %s completed" % build)
+        if not self.building_jobs.has_key(build):
+            self.log.warning("Build %s not found (may have been canceled)" % (
+                    build))
+            # Or triggered externally, or triggered before zuul started,
+            # or restarted
+            return False
+        change = self.building_jobs[build]
+        self.log.debug("Found change %s which triggered completed build %s" % (
+                change, build))
+
+        del self.building_jobs[build]
+
+        change.setResult(build)
+        self.log.info("Change %s status is now:\n %s" % (
+                change, change.formatStatus()))
+
+        if change.areAllJobsComplete():
+            self.log.debug("All jobs for change %s are complete" % change)
+            self.possiblyReportChange(change)
+        else:
+            # There may be jobs that depended on jobs that are now complete
+            self.log.debug("All jobs for change %s are not yet complete" % (
+                    change))
+            self.launchJobs(change)
+        return True
+
+    def possiblyReportChange(self, change):
+        self.log.debug("Possibly reporting change %s" % change)
+        self.reportChange(change)
+
+    def reportChange(self, change):
+        self.log.debug("Reporting change %s" % change)
+        ret = None
+        if change.didAllJobsSucceed():
+            action = self.success_action
+        else:
+            action = self.failure_action
+        try:
+            self.log.info("Reporting change %s, action: %s" % (
+                    change, action))
+            ret = self.sched.trigger.report(change, change.formatReport(),
+                                            action)
+            if ret:
+                self.log.error("Reporting change %s received: %s" % (
+                        change, ret))
+                print ret
+        except:
+            self.log.exception("Exception while reporting:")
+        return ret
+
+class IndependentQueueManager(BaseQueueManager):
+    log = logging.getLogger("zuul.IndependentQueueManager")
+    pass
+
+class DependentQueueManager(BaseQueueManager):
+    log = logging.getLogger("zuul.DependentQueueManager")
+
+    def __init__(self, *args, **kwargs):
+        super(DependentQueueManager, self).__init__(*args, **kwargs)
+        self.change_queues = []
+
+    def _postConfig(self):
+        super(DependentQueueManager, self)._postConfig()
+        self.buildChangeQueues()
+
+    def buildChangeQueues(self):
+        self.log.debug("Building shared change queues")
+        change_queues = []
+
+        for project in self.sched.projects.values():
+            if project.hasQueue(self.name):
+                change_queue = ChangeQueue(self.name)
+                change_queue.addProject(project)
+                change_queues.append(change_queue)
+                self.log.debug("Created queue: %s" % change_queue)
+
+        self.log.debug("Combining shared queues")
+        new_change_queues = []
+        for a in change_queues:
+            merged_a = False
+            for b in new_change_queues:
+                if not a.getJobs().isdisjoint(b.getJobs()):
+                    self.log.debug("Merging queue %s into %s" % (a, b))
+                    b.mergeChangeQueue(a)
+                    merged_a = True
+                    break  # this breaks out of 'for b' and continues 'for a'
+            if not merged_a:
+                self.log.debug("Keeping queue %s" % (a))
+                new_change_queues.append(a)
+        
+        self.change_queues = new_change_queues
+        self.log.info("  Shared change queues:")
+        for x in self.change_queues:
+            self.log.info("    %s" % x)
+
+    def getQueue(self, project):
+        for queue in self.change_queues:
+            if project in queue.projects:
+                return queue
+        self.log.error("Unable to find change queue for project %s" % project)
+            
+    def addChange(self, change):
+        self.log.debug("Adding change %s" % change)
+        change_queue = self.getQueue(change.project)
+        self.log.debug("Adding change %s to queue %s" % (change, change_queue))
+        change_queue.enqueueChange(change)
+        super(DependentQueueManager, self).addChange(change)
+
+    def _getDependentChanges(self, change):
+        changes = []
+        while change.change_ahead:
+            changes.append(change.change_ahead)
+            change = change.change_ahead
+        self.log.info("Change %s depends on changes %s" % (change, changes))
+        return changes
+
+    def launchJobs(self, change):
+        self.log.debug("Launching jobs for change %s" % change)
+        dependent_changes = self._getDependentChanges(change)
+        for job in change.findJobsToRun():
+            self.log.debug("Found job %s for change %s" % (job, change))
+            try:
+                build = self.sched.launcher.launch(job, change, 
+                                                   dependent_changes)
+                self.building_jobs[build] = change
+                self.log.debug("Adding build %s of job %s to change %s" % (
+                        build, job, change))
+                change.addBuild(build)
+            except:
+                self.log.exception("Exception while launching job %s for change %s:" % (
+                        job, change))
+        if change.change_behind:
+            self.log.debug("Launching jobs for change %s, behind change %s" % (
+                    change.change_behind, change))
+            self.launchJobs(change.change_behind)
+
+    def cancelJobs(self, change):
+        self.log.debug("Cancel jobs for change %s" % change)
+        to_remove = []
+        change.resetAllBuilds()
+        for build, build_change in self.building_jobs.items():
+            if build_change == change:
+                self.log.debug("Found build %s for change %s to cancel" % (
+                        build, change))
+                try:
+                    self.sched.launcher.cancel(build)
+                except:
+                    self.log.exception("Exception while canceling build %s for change %s" % (
+                            build, change))
+                to_remove.append(build)
+        for build in to_remove:
+            self.log.debug("Removing build %s from running builds" % build)
+            del self.building_jobs[build]
+        if change.change_behind:
+            self.log.debug("Canceling jobs for change %s, behind change %s" % (
+                    change.change_behind, change))
+            self.cancelJobs(change.change_behind)
+
+    def possiblyReportChange(self, change):
+        self.log.debug("Possibly reporting change %s" % change)
+        if not change.change_ahead:
+            self.log.debug("Change %s is at the front of the queue, reporting" % (
+                    change))
+            ret = self.reportChange(change)
+            self.log.debug("Removing reported change %s from queue" % change)
+            change.delete()
+            change.queue.dequeueChange(change)
+            merged = (not ret)
+            if merged:
+                merged = self.sched.trigger.isMerged(change)
+            succeeded = change.didAllJobsSucceed()
+            self.log.info("Reported change %s status: all-succeeded: %s, merged: %s" % (
+                    change, succeeded, merged))
+                    
+            if not (succeeded and merged):
+                self.log.debug("Reported change %s failed tests or failed to merge" % (
+                        change))
+                # The merge or test failed, re-run all jobs behind this one
+                if change.change_behind:
+                    self.log.info("Canceling/relaunching jobs for change %s behind failed change %s" % (
+                            change.change_behind, change))
+                    self.cancelJobs(change.change_behind)
+                    self.launchJobs(change.change_behind)
+        # If the change behind this is ready, notify
+        if (change.change_behind and 
+            change.change_behind.areAllJobsComplete()):
+            self.log.info("Change %s behind change %s is ready, possibly reporting" % (
+                    change.change_behind, change))
+            self.possiblyReportChange(change.change_behind)
diff --git a/zuul/trigger/__init__.py b/zuul/trigger/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/zuul/trigger/__init__.py
diff --git a/zuul/trigger/gerrit.py b/zuul/trigger/gerrit.py
new file mode 100644
index 000000000..870820727
--- /dev/null
+++ b/zuul/trigger/gerrit.py
@@ -0,0 +1,92 @@
+# Copyright 2012 Hewlett-Packard Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import threading
+import logging
+from zuul.lib import gerrit
+from zuul.model import TriggerEvent
+
+class GerritEventConnector(threading.Thread):
+    """Move events from Gerrit to the scheduler."""
+
+    log = logging.getLogger("zuul.GerritEventConnector")
+
+    def __init__(self, gerrit, sched):
+        super(GerritEventConnector, self).__init__()
+        self.gerrit = gerrit
+        self.sched = sched
+
+
+    def _handleEvent(self):
+        data = self.gerrit.getEvent()
+        event = TriggerEvent()
+        event.type = data.get('type')
+        change = data.get('change')
+        if change:
+            event.project_name = change.get('project')
+            event.branch = change.get('branch')
+            event.change_number = change.get('number')
+            patchset = data.get('patchSet')
+            if patchset:
+                event.patch_number = patchset.get('number')
+            event.approvals = data.get('approvals')
+        self.sched.addEvent(event)
+
+
+    def run(self):
+        while True:
+            try:
+                self._handleEvent()
+            except:
+                self.log.exception("Exception moving Gerrit event:")
+
+
+class Gerrit(object):
+    log = logging.getLogger("zuul.Gerrit")
+
+    def __init__(self, config, sched):
+        self.sched = sched
+        server = config.get('gerrit', 'server')
+        user = config.get('gerrit', 'user')
+        if config.has_option('gerrit', 'sshkey'):
+            sshkey = config.get('gerrit', 'sshkey')
+        else:
+            sshkey = None
+        self.gerrit = gerrit.Gerrit(server, user, sshkey)
+        self.gerrit.startWatching()
+        self.gerrit_connector = GerritEventConnector(
+            self.gerrit, sched)
+        self.gerrit_connector.start()
+
+        
+    def report(self, change, message, action):
+        self.log.debug("Report change %s, action %s, message: %s" %
+                       (change, action, message))
+        changeid = '%s,%s' % (change.number, change.patchset)
+        return self.gerrit.review(change.project.name, changeid,
+                                  message, action)
+
+
+    def isMerged(self, change):
+        self.log.debug("Checking if change %s is merged", change)
+        data = self.gerrit.query(change.number)
+        if not data:
+            return False
+        status = data.get('status')
+        if not status:
+            return False
+        self.log.debug("Change %s status: %s" % (change, status))
+        if status == 'MERGED' or status == 'SUBMITTED':
+            return True
+