Rewrote toposort to handle loops in Step graph. Simpler implementation
authorSapan Bhatia <gwsapan@gmail.com>
Tue, 11 Mar 2014 21:48:30 +0000 (17:48 -0400)
committerSapan Bhatia <gwsapan@gmail.com>
Tue, 11 Mar 2014 21:48:30 +0000 (17:48 -0400)
planetstack/observer/event_loop.py
planetstack/observer/toposort.py [changed mode: 0755->0644]

index bdf5ce3..6b77236 100644 (file)
@@ -18,303 +18,259 @@ from util.logger import Logger, logging, logger
 from planetstack.config import Config
 from observer.steps import *
 from syncstep import SyncStep
+from toposort import toposort
 
 debug_mode = False
 
 logger = Logger(level=logging.INFO)
 
 class StepNotReady(Exception):
-    pass
-
-def toposort(g, steps=None):
-    if (not steps):
-        keys = set(g.keys())
-        values = set({})
-        for v in g.values():
-            values=values | set(v)
-        
-        steps=list(keys|values)
-    reverse = {}
-
-    for k,v in g.items():
-        for rk in v:
-            try:
-                reverse[rk].append(k)
-            except:
-                reverse[rk]=k
-
-    sources = []
-    for k,v in g.items():
-        if not reverse.has_key(k):
-            sources.append(k)
-
-
-    for k,v in reverse.iteritems():
-        if (not v):
-            sources.append(k)
-
-    order = []
-    marked = []
-
-    while sources:
-        n = sources.pop()
-        try:
-            for m in g[n]:
-                if m not in marked:
-                    sources.append(m)
-                    marked.append(m)
-        except KeyError:
-            pass
-        if (n in steps):
-            order.append(n)
-
-    order.reverse()
-    order.extend(set(steps)-set(order))
-    return order
+       pass
 
 class NoOpDriver:
-    def __init__(self):
-         self.enabled = True
+       def __init__(self):
+                self.enabled = True
 
 class PlanetStackObserver:
-    #sync_steps = [SyncNetworks,SyncNetworkSlivers,SyncSites,SyncSitePrivileges,SyncSlices,SyncSliceMemberships,SyncSlivers,SyncSliverIps,SyncExternalRoutes,SyncUsers,SyncRoles,SyncNodes,SyncImages,GarbageCollector]
-    sync_steps = []
-
-    def __init__(self):
-        # The Condition object that gets signalled by Feefie events
-        self.step_lookup = {}
-        self.load_sync_step_modules()
-        self.load_sync_steps()
-        self.event_cond = threading.Condition()
-
-
-        self.driver_kind = getattr(Config(), "observer_driver", "openstack")
-        if self.driver_kind=="openstack":
-            self.driver = OpenStackDriver()
-        else:
-            self.driver = NoOpDriver()
-
-    def wait_for_event(self, timeout):
-        self.event_cond.acquire()
-        self.event_cond.wait(timeout)
-        self.event_cond.release()
-
-    def wake_up(self):
-        logger.info('Wake up routine called. Event cond %r'%self.event_cond)
-        self.event_cond.acquire()
-        self.event_cond.notify()
-        self.event_cond.release()
-
-    def load_sync_step_modules(self, step_dir=None):
-        if step_dir is None:
-            if hasattr(Config(), "observer_steps_dir"):
-                step_dir = Config().observer_steps_dir
-            else:
-                step_dir = "/opt/planetstack/observer/steps"
-
-        for fn in os.listdir(step_dir):
-            pathname = os.path.join(step_dir,fn)
-            if os.path.isfile(pathname) and fn.endswith(".py") and (fn!="__init__.py"):
-                module = imp.load_source(fn[:-3],pathname)
-                for classname in dir(module):
-                    c = getattr(module, classname, None)
-
-                    # make sure 'c' is a descendent of SyncStep and has a
-                    # provides field (this eliminates the abstract base classes
-                    # since they don't have a provides)
-
-                    if inspect.isclass(c) and issubclass(c, SyncStep) and hasattr(c,"provides") and (c not in self.sync_steps):
-                        self.sync_steps.append(c)
-        logger.info('loaded sync steps: %s' % ",".join([x.__name__ for x in self.sync_steps]))
-        # print 'loaded sync steps: %s' % ",".join([x.__name__ for x in self.sync_steps])
-
-    def load_sync_steps(self):
-        dep_path = Config().observer_dependency_graph
-        logger.info('Loading model dependency graph from %s' % dep_path)
-        try:
-            # This contains dependencies between records, not sync steps
-            self.model_dependency_graph = json.loads(open(dep_path).read())
-        except Exception,e:
-            raise e
-
-        try:
-            backend_path = Config().observer_pl_dependency_graph
-            logger.info('Loading backend dependency graph from %s' % backend_path)
-            # This contains dependencies between backend records
-            self.backend_dependency_graph = json.loads(open(backend_path).read())
-        except Exception,e:
-            logger.info('Backend dependency graph not loaded')
-            # We can work without a backend graph
-            self.backend_dependency_graph = {}
-
-        provides_dict = {}
-        for s in self.sync_steps:
-            self.step_lookup[s.__name__] = s 
-            for m in s.provides:
-                try:
-                    provides_dict[m.__name__].append(s.__name__)
-                except KeyError:
-                    provides_dict[m.__name__]=[s.__name__]
-
-                
-        step_graph = {}
-        for k,v in self.model_dependency_graph.iteritems():
-            try:
-                for source in provides_dict[k]:
-                    for m in v:
-                        try:
-                            for dest in provides_dict[m]:
-                                # no deps, pass
-                                try:
-                                    step_graph[source].append(dest)
-                                except:
-                                    step_graph[source]=[dest]
-                        except KeyError:
-                            pass
-                    
-            except KeyError:
-                pass
-                # no dependencies, pass
-        
-        #import pdb
-        #pdb.set_trace()
-        if (self.backend_dependency_graph):
-            backend_dict = {}
-            for s in self.sync_steps:
-                for m in s.serves:
-                    backend_dict[m]=s.__name__
-                    
-            for k,v in backend_dependency_graph.iteritems():
-                try:
-                    source = backend_dict[k]
-                    for m in v:
-                        try:
-                            dest = backend_dict[m]
-                        except KeyError:
-                            # no deps, pass
-                            pass
-                        step_graph[source]=dest
-                        
-                except KeyError:
-                    pass
-                    # no dependencies, pass
-
-        dependency_graph = step_graph
-
-        self.ordered_steps = toposort(dependency_graph, map(lambda s:s.__name__,self.sync_steps))
-        print "Order of steps=",self.ordered_steps
-        self.load_run_times()
-        
-
-    def check_duration(self, step, duration):
-        try:
-            if (duration > step.deadline):
-                logger.info('Sync step %s missed deadline, took %.2f seconds'%(step.name,duration))
-        except AttributeError:
-            # S doesn't have a deadline
-            pass
-
-    def update_run_time(self, step):
-        self.last_run_times[step.__name__]=time.time()
-
-    def check_schedule(self, step):
-        time_since_last_run = time.time() - self.last_run_times.get(step.__name__, 0)
-        try:
-            if (time_since_last_run < step.requested_interval):
-                raise StepNotReady
-        except AttributeError:
-            logger.info('Step %s does not have requested_interval set'%step.__name__)
-            raise StepNotReady
-    
-    def load_run_times(self):
-        try:
-            jrun_times = open('/tmp/observer_run_times').read()
-            self.last_run_times = json.loads(jrun_times)
-        except:
-            self.last_run_times={}
-            for e in self.ordered_steps:
-                self.last_run_times[e]=0
-
-
-    def save_run_times(self):
-        run_times = json.dumps(self.last_run_times)
-        open('/tmp/observer_run_times','w').write(run_times)
-
-    def check_class_dependency(self, step, failed_steps):
-        step.dependenices = []
-        for obj in step.provides:
-            step.dependenices.extend(self.model_dependency_graph.get(obj.__name__, []))
-        for failed_step in failed_steps:
-            if (failed_step in step.dependencies):
-                raise StepNotReady
-
-    def run(self):
-        if not self.driver.enabled:
-            return
-        if (self.driver_kind=="openstack") and (not self.driver.has_openstack):
-            return
-
-        while True:
-            try:
-                logger.info('Waiting for event')
-                tBeforeWait = time.time()
-                self.wait_for_event(timeout=30)
-                logger.info('Observer woke up')
-
-                # Set of whole steps that failed
-                failed_steps = []
-
-                # Set of individual objects within steps that failed
-                failed_step_objects = set()
-
-                for S in self.ordered_steps:
-                    step = self.step_lookup[S]
-                    start_time=time.time()
-                    
-                    sync_step = step(driver=self.driver)
-                    sync_step.__name__ = step.__name__
-                    sync_step.dependencies = []
-                    try:
-                        mlist = sync_step.provides
-                        
-                        for m in mlist:
-                            sync_step.dependencies.extend(self.model_dependency_graph[m.__name__])
-                    except KeyError:
-                        pass
-                    sync_step.debug_mode = debug_mode
-
-                    should_run = False
-                    try:
-                        # Various checks that decide whether
-                        # this step runs or not
-                        self.check_class_dependency(sync_step, failed_steps) # dont run Slices if Sites failed
-                        self.check_schedule(sync_step) # dont run sync_network_routes if time since last run < 1 hour
-                        should_run = True
-                    except StepNotReady:
-                        logging.info('Step not ready: %s'%sync_step.__name__)
-                        failed_steps.append(sync_step)
-                    except:
-                        failed_steps.append(sync_step)
-
-                    if (should_run):
-                        try:
-                            duration=time.time() - start_time
-
-                            logger.info('Executing step %s' % sync_step.__name__)
-
-                            # ********* This is the actual sync step
-                            #import pdb
-                            #pdb.set_trace()
-                            failed_objects = sync_step(failed=list(failed_step_objects))
-
-
-                            self.check_duration(sync_step, duration)
-                            if failed_objects:
-                                failed_step_objects.update(failed_objects)
-                            self.update_run_time(sync_step)
-                        except:
-                            failed_steps.append(S)
-                self.save_run_times()
-            except:
-                logger.log_exc("Exception in observer run loop")
-                traceback.print_exc()
+       #sync_steps = [SyncNetworks,SyncNetworkSlivers,SyncSites,SyncSitePrivileges,SyncSlices,SyncSliceMemberships,SyncSlivers,SyncSliverIps,SyncExternalRoutes,SyncUsers,SyncRoles,SyncNodes,SyncImages,GarbageCollector]
+       sync_steps = []
+
+       def __init__(self):
+               # The Condition object that gets signalled by Feefie events
+               self.step_lookup = {}
+               self.load_sync_step_modules()
+               self.load_sync_steps()
+               self.event_cond = threading.Condition()
+
+
+               self.driver_kind = getattr(Config(), "observer_driver", "openstack")
+               if self.driver_kind=="openstack":
+                       self.driver = OpenStackDriver()
+               else:
+                       self.driver = NoOpDriver()
+
+       def wait_for_event(self, timeout):
+               self.event_cond.acquire()
+               self.event_cond.wait(timeout)
+               self.event_cond.release()
+
+       def wake_up(self):
+               logger.info('Wake up routine called. Event cond %r'%self.event_cond)
+               self.event_cond.acquire()
+               self.event_cond.notify()
+               self.event_cond.release()
+
+       def load_sync_step_modules(self, step_dir=None):
+               if step_dir is None:
+                       if hasattr(Config(), "observer_steps_dir"):
+                               step_dir = Config().observer_steps_dir
+                       else:
+                               step_dir = "/opt/planetstack/observer/steps"
+
+               for fn in os.listdir(step_dir):
+                       pathname = os.path.join(step_dir,fn)
+                       if os.path.isfile(pathname) and fn.endswith(".py") and (fn!="__init__.py"):
+                               module = imp.load_source(fn[:-3],pathname)
+                               for classname in dir(module):
+                                       c = getattr(module, classname, None)
+
+                                       # make sure 'c' is a descendent of SyncStep and has a
+                                       # provides field (this eliminates the abstract base classes
+                                       # since they don't have a provides)
+
+                                       if inspect.isclass(c) and issubclass(c, SyncStep) and hasattr(c,"provides") and (c not in self.sync_steps):
+                                               self.sync_steps.append(c)
+               logger.info('loaded sync steps: %s' % ",".join([x.__name__ for x in self.sync_steps]))
+               # print 'loaded sync steps: %s' % ",".join([x.__name__ for x in self.sync_steps])
+
+       def load_sync_steps(self):
+               dep_path = Config().observer_dependency_graph
+               logger.info('Loading model dependency graph from %s' % dep_path)
+               try:
+                       # This contains dependencies between records, not sync steps
+                       self.model_dependency_graph = json.loads(open(dep_path).read())
+               except Exception,e:
+                       raise e
+
+               try:
+                       backend_path = Config().observer_pl_dependency_graph
+                       logger.info('Loading backend dependency graph from %s' % backend_path)
+                       # This contains dependencies between backend records
+                       self.backend_dependency_graph = json.loads(open(backend_path).read())
+               except Exception,e:
+                       logger.info('Backend dependency graph not loaded')
+                       # We can work without a backend graph
+                       self.backend_dependency_graph = {}
+
+               provides_dict = {}
+               for s in self.sync_steps:
+                       self.step_lookup[s.__name__] = s 
+                       for m in s.provides:
+                               try:
+                                       provides_dict[m.__name__].append(s.__name__)
+                               except KeyError:
+                                       provides_dict[m.__name__]=[s.__name__]
+
+                               
+               step_graph = {}
+               for k,v in self.model_dependency_graph.iteritems():
+                       try:
+                               for source in provides_dict[k]:
+                                       for m in v:
+                                               try:
+                                                       for dest in provides_dict[m]:
+                                                               # no deps, pass
+                                                               try:
+                                                                       if (dest not in step_graph[source]):
+                                                                               step_graph[source].append(dest)
+                                                               except:
+                                                                       step_graph[source]=[dest]
+                                               except KeyError:
+                                                       pass
+                                       
+                       except KeyError:
+                               pass
+                               # no dependencies, pass
+               
+               #import pdb
+               #pdb.set_trace()
+               if (self.backend_dependency_graph):
+                       backend_dict = {}
+                       for s in self.sync_steps:
+                               for m in s.serves:
+                                       backend_dict[m]=s.__name__
+                                       
+                       for k,v in backend_dependency_graph.iteritems():
+                               try:
+                                       source = backend_dict[k]
+                                       for m in v:
+                                               try:
+                                                       dest = backend_dict[m]
+                                               except KeyError:
+                                                       # no deps, pass
+                                                       pass
+                                               step_graph[source]=dest
+                                               
+                               except KeyError:
+                                       pass
+                                       # no dependencies, pass
+
+               dependency_graph = step_graph
+
+               self.ordered_steps = toposort(dependency_graph, map(lambda s:s.__name__,self.sync_steps))
+               print "Order of steps=",self.ordered_steps
+               self.load_run_times()
+               
+
+       def check_duration(self, step, duration):
+               try:
+                       if (duration > step.deadline):
+                               logger.info('Sync step %s missed deadline, took %.2f seconds'%(step.name,duration))
+               except AttributeError:
+                       # S doesn't have a deadline
+                       pass
+
+       def update_run_time(self, step):
+               self.last_run_times[step.__name__]=time.time()
+
+       def check_schedule(self, step):
+               time_since_last_run = time.time() - self.last_run_times.get(step.__name__, 0)
+               try:
+                       if (time_since_last_run < step.requested_interval):
+                               raise StepNotReady
+               except AttributeError:
+                       logger.info('Step %s does not have requested_interval set'%step.__name__)
+                       raise StepNotReady
+       
+       def load_run_times(self):
+               try:
+                       jrun_times = open('/tmp/observer_run_times').read()
+                       self.last_run_times = json.loads(jrun_times)
+               except:
+                       self.last_run_times={}
+                       for e in self.ordered_steps:
+                               self.last_run_times[e]=0
+
+
+       def save_run_times(self):
+               run_times = json.dumps(self.last_run_times)
+               open('/tmp/observer_run_times','w').write(run_times)
+
+       def check_class_dependency(self, step, failed_steps):
+               step.dependenices = []
+               for obj in step.provides:
+                       step.dependenices.extend(self.model_dependency_graph.get(obj.__name__, []))
+               for failed_step in failed_steps:
+                       if (failed_step in step.dependencies):
+                               raise StepNotReady
+
+       def run(self):
+               if not self.driver.enabled:
+                       return
+               if (self.driver_kind=="openstack") and (not self.driver.has_openstack):
+                       return
+
+               while True:
+                       try:
+                               logger.info('Waiting for event')
+                               tBeforeWait = time.time()
+                               self.wait_for_event(timeout=30)
+                               logger.info('Observer woke up')
+
+                               # Set of whole steps that failed
+                               failed_steps = []
+
+                               # Set of individual objects within steps that failed
+                               failed_step_objects = set()
+
+                               for S in self.ordered_steps:
+                                       step = self.step_lookup[S]
+                                       start_time=time.time()
+                                       
+                                       sync_step = step(driver=self.driver)
+                                       sync_step.__name__ = step.__name__
+                                       sync_step.dependencies = []
+                                       try:
+                                               mlist = sync_step.provides
+                                               
+                                               for m in mlist:
+                                                       sync_step.dependencies.extend(self.model_dependency_graph[m.__name__])
+                                       except KeyError:
+                                               pass
+                                       sync_step.debug_mode = debug_mode
+
+                                       should_run = False
+                                       try:
+                                               # Various checks that decide whether
+                                               # this step runs or not
+                                               self.check_class_dependency(sync_step, failed_steps) # dont run Slices if Sites failed
+                                               self.check_schedule(sync_step) # dont run sync_network_routes if time since last run < 1 hour
+                                               should_run = True
+                                       except StepNotReady:
+                                               logging.info('Step not ready: %s'%sync_step.__name__)
+                                               failed_steps.append(sync_step)
+                                       except:
+                                               failed_steps.append(sync_step)
+
+                                       if (should_run):
+                                               try:
+                                                       duration=time.time() - start_time
+
+                                                       logger.info('Executing step %s' % sync_step.__name__)
+
+                                                       # ********* This is the actual sync step
+                                                       #import pdb
+                                                       #pdb.set_trace()
+                                                       failed_objects = sync_step(failed=list(failed_step_objects))
+
+
+                                                       self.check_duration(sync_step, duration)
+                                                       if failed_objects:
+                                                               failed_step_objects.update(failed_objects)
+                                                       self.update_run_time(sync_step)
+                                               except:
+                                                       failed_steps.append(S)
+                               self.save_run_times()
+                       except:
+                               logger.log_exc("Exception in observer run loop")
+                               traceback.print_exc()
old mode 100755 (executable)
new mode 100644 (file)
index 959cea3..a2c9389
@@ -5,58 +5,69 @@ import traceback
 import commands
 import threading
 import json
+import pdb
 
 from datetime import datetime
 from collections import defaultdict
 
+# Topological sort
+# Notes:
+# - Uses a stack instead of recursion
+# - Forfeits optimization involving tracking currently visited nodes
 def toposort(g, steps=None):
+       # Get set of all nodes, including those without outgoing edges
+       keys = set(g.keys())
+       values = set({})
+       for v in g.values():
+               values=values | set(v)
+       
+       all_nodes=list(keys|values)
        if (not steps):
-               keys = set(g.keys())
-               values = set({})
-               for v in g.values():
-                       values=values | set(v)
-               
-               steps=list(keys|values)
+               steps = all_nodes
 
-       reverse = {}
+       # Final order
+       order = []
+
+       # DFS stack, not using recursion
+       stack = []
+
+       # Unmarked set
+       unmarked = all_nodes
 
-       for k,v in g.items():
-               for rk in v:
+       # visiting = [] - skip, don't expect 1000s of nodes, |E|/|V| is small
+
+       while unmarked:
+               stack.insert(0,unmarked[0]) # push first unmarked
+
+               while (stack):
+                       n = stack[0]
+                       add = True
                        try:
-                               reverse[rk].append(k)
-                       except:
-                               reverse[rk]=k
+                               for m in g[n]:
+                                       if (m in unmarked):
+                                               if (m not in stack):
+                                                       add = False
+                                                       stack.insert(0,m)
+                                               else:
+                                                       # Should not happen, if so there's a loop
+                                                       print 'Loop at %s'%m
+                       except KeyError:
+                               pass
+                       if (add):
+                               if (n in steps):
+                                       order.append(n)
+                               item = stack.pop(0)
+                               unmarked.remove(item)
 
-       sources = []
-       for k,v in g.items():
-               if not reverse.has_key(k):
-                       sources.append(k)
+       noorder = list(set(steps) - set(order))
+       return order + noorder
 
-       for k,v in reverse.iteritems():
-               if (not v):
-                       sources.append(k)
+def main():
+       graph_file=open('planetstack.deps').read()
+       g = json.loads(graph_file)
+       print toposort(g)
 
-       order = []
-       marked = []
-
-       while sources:
-               n = sources.pop(0)
-               try:
-                       for m in g[n]:
-                               if m not in marked:
-                                       sources.append(m)
-                                       marked.append(m)
-               except KeyError:
-                       pass
-               if (n in steps):
-                       order.append(n)
-
-       order.reverse()
-
-       return order
-
-graph_file=open('model-deps').read()
-g = json.loads(graph_file)
-print toposort(g)
+if (__name__=='__main__'):
+       main()
 
 #print toposort({'a':'b','b':'c','c':'d','d':'c'},['d','c','b','a'])