Split dhcp handler in submodules (refs #2).

[software/pymin.git] / pymin / procman.py

diff --git a/pymin/procman.py b/pymin/procman.py
index 810481d3a2c9c8ada37f2515aae06a8a53190305..269117b7b202196a99871ff8b042e179a4a8827e 100644 (file)
--- a/pymin/procman.py
+++ b/pymin/procman.py
@@ -4,54 +4,71 @@ import os
 import errno
 import signal
 import subprocess
 import errno
 import signal
 import subprocess

+import logging ; log = logging.getLogger('pymin.procman')
+
+__all__ = ('ProcessManager', 'manager', 'register', 'unregister', 'once',
+           'start', 'stop', 'restart', 'kill', 'get', 'has', 'sigchild_handler')

 
 class ProcessInfo:
     def __init__(self, name, command, callback=None, persist=False,
 
 class ProcessInfo:
     def __init__(self, name, command, callback=None, persist=False,

-                       args=None, kw=None, max_errors=3):
-        self.name = name
+                 max_errors=3, args=None, kwargs=None):
+        self._name = name

         self.command = command
         self.callback = callback
         if args is None: args = list()
         self.args = args
         self.command = command
         self.callback = callback
         if args is None: args = list()
         self.args = args

-        if kw is None: kw = dict()
-        self.kw = kw
+        if kwargs is None: kwargs = dict()
+        self.kwargs = kwargs

         self.persist = persist
         self.max_errors = max_errors
         self.clear()
     def clear(self):
         self.persist = persist
         self.max_errors = max_errors
         self.clear()
     def clear(self):

-        self.dont_run = False
-        self.signal = None
-        self.process = None
-        self.error_count = 0
-        self.last_return = None
-        self.running = False
+        self._dont_run = False
+        self._signal = None
+        self._process = None
+        self._error_count = 0

     def start(self):
         assert self.process is None
         self.restart()
     def restart(self):
         self.clear()
     def start(self):
         assert self.process is None
         self.restart()
     def restart(self):
         self.clear()

-        self.process = subprocess.Popen(self.command, *self.args, **self.kw)
-        self.running = True
+        log.debug(u'ProcessInfo.restart(): executing %s', self.command)
+        self._process = subprocess.Popen(self.command,
+                                         *self.args, **self.kwargs)

     def stop(self):
         assert self.process is not None
     def stop(self):
         assert self.process is not None

-        self.dont_run = True
-        if self.signal == signal.SIGTERM or self.signal == signal.SIGKILL:
+        self._dont_run = True
+        if self._signal == signal.SIGTERM or self._signal == signal.SIGKILL:

             # Allready stopped, kill it
             self.kill(signal.SIGKILL)
         else:
             # Stop it
             self.kill(signal.SIGTERM)
     def kill(self, signum):
             # Allready stopped, kill it
             self.kill(signal.SIGKILL)
         else:
             # Stop it
             self.kill(signal.SIGTERM)
     def kill(self, signum):

+        log.debug(u'ProcessInfo.kill(): killing pid %s with signal %s',
+                      self.process.pid, signum)

         assert self.process is not None
         assert self.process is not None

-        os.kill(pi.process.pid, signum)
-        self.signal = signum
+        os.kill(self.process.pid, signum)
+        self._signal = signum
+    @property
+    def running(self):
+        return self.process is not None and self.process.poll() is None
+    @property
+    def name(self):
+        return self._name
+    @property
+    def process(self):
+        return self._process
+    @property
+    def error_count(self):
+        return self._error_count

     def __repr__(self):
         pid = None
         if self.process is not None:
             pid = self.process.pid
         return 'ProcessInfo(name=%s, pid=%s command=%s, persist=%s, cb=%s)' % (
                     self.name, pid, self.command, self.persist,
     def __repr__(self):
         pid = None
         if self.process is not None:
             pid = self.process.pid
         return 'ProcessInfo(name=%s, pid=%s command=%s, persist=%s, cb=%s)' % (
                     self.name, pid, self.command, self.persist,

-                    self.callback.__name__)
+                    self.callback and self.callback.__name__ or None)

 
 class ProcessManager:
 
 
 class ProcessManager:
 


@@ -59,56 +76,136 @@ class ProcessManager:
         self.services = dict()
         self.namemap = dict()
         self.pidmap = dict()
         self.services = dict()
         self.namemap = dict()
         self.pidmap = dict()

+        log.debug(u'ProcessManager()')

 
 

-    def register(self, name, command, callback=None, persist=False,
-                       *args, **kw):
-        self.services[name] = ProcessInfo(name, command, callback, persist,
-                                          args, kw)
+    def register(self, name, command=None, callback=None, persist=False,
+                max_errors=3, *args, **kwargs):
+        log.debug(u'ProcessManager.register(%s, %s, %s, %s, %s, %s, %s)',
+                  name, command, callback, persist, max_errors, args, kwargs)
+        if not isinstance(name, ProcessInfo):
+            pi = ProcessInfo(name, command, callback, persist, max_errors,
+                             args, kwargs)
+        else:
+            pi = name
+            name = pi.name
+        assert not self.has(name)
+        self.services[name] = pi
+        return pi

 
     def unregister(self, name):
 
     def unregister(self, name):

+        log.debug(u'ProcessManager.unregister(%s)', name)
+        if isinstance(name, ProcessInfo):
+            pi = name
+            name = pi.name
+        else:
+            pi = self.services[name]

         del self.services[name]
         del self.services[name]

+        return pi

 
     def _call(self, pi):
         pi.start()
         self.namemap[pi.name] = self.pidmap[pi.process.pid] = pi
 
 
     def _call(self, pi):
         pi.start()
         self.namemap[pi.name] = self.pidmap[pi.process.pid] = pi
 

-    def call(self, name, command, callback=None, persist=False, *args, **kw):
-        pi = ProcessInfo(name, command, callback, persist, args, kw)
+    def once(self, name, command=None, callback=None, persist=False,
+                max_errors=3, *args, **kwargs):
+        log.debug(u'ProcessManager.once(%s, %s, %s, %s, %s, %s, %s)',
+                  name, command, callback, persist, max_errors, args, kwargs)
+        if not isinstance(name, ProcessInfo):
+            pi = ProcessInfo(name, command, callback, persist, max_errors,
+                             args, kwargs)
+        else:
+            pi = name
+            name = pi.name
+        assert not self.has(name)

         self._call(pi)
         self._call(pi)

+        return pi

 
     def start(self, name):
 
     def start(self, name):

-        assert name not in self.namemap
-        self._call(self.services[name])
+        log.debug(u'ProcessManager.start(%s)', name)
+        if isinstance(name, ProcessInfo):
+            name = name.name
+        if name not in self.namemap:
+            self._call(self.services[name])
+            return True
+        return False

 
     def stop(self, name):
 
     def stop(self, name):

-        assert name in self.namemap
-        self.namemap[name].stop(name)
+        log.debug(u'ProcessManager.stop(%s)', name)
+        if isinstance(name, ProcessInfo):
+            name = name.name
+        if name in self.namemap:
+            self.namemap[name].stop()
+            return True
+        return False
+
+    def restart(self, name):
+        log.debug(u'ProcessManager.restart(%s)', name)
+        if isinstance(name, ProcessInfo):
+            name = name.name
+        # we have to check first in namemap in case is an unregistered
+        # process (added with once())
+        if name in self.namemap:
+            pi = self.namemap[name]
+            # the process will change its PID, so we delete it while we know it
+            del self.pidmap[pi.process.pid]
+            pi.stop()
+            pi.process.wait()
+            pi.restart()
+            # add the new PID
+            self.pidmap[pi.process.pid] = pi
+            return True
+        else:
+            self.start(name)
+            return False

 
     def kill(self, name, signum):
 
     def kill(self, name, signum):

-        assert name in self.namemap
-        self.namemap[name].kill(name, stop)
+        log.debug(u'ProcessManager.kill(%s, %s)', name, signum)
+        if isinstance(name, ProcessInfo):
+            name = name.name
+        if name in self.namemap:
+            self.namemap[name].kill(name, stop)
+            return True
+        return False

 
 

-    def sigchild_handler(self, signum):
+    def sigchild_handler(self, signum, stack_frame=None):
+        log.debug(u'ProcessManager.sigchild_handler(%s)', signum)

         try:
             (pid, status) = os.waitpid(-1, os.WNOHANG)
         except OSError, e:
         try:
             (pid, status) = os.waitpid(-1, os.WNOHANG)
         except OSError, e:

-            if e.errno is e.ECHILD:
+            log.debug(u'ProcessManager.sigchild_handler(): OSError')
+            if e.errno is errno.ECHILD:
+                log.debug(u'ProcessManager.sigchild_handler(): OSError ECHILD')

                 return
             raise
                 return
             raise

+        log.debug(u'ProcessManager.sigchild_handler: pid=%s, status=%s',
+                      pid, status)

         while pid:
             if pid in self.pidmap:
                 p = self.pidmap[pid]
         while pid:
             if pid in self.pidmap:
                 p = self.pidmap[pid]

+                p.process.returncode = status

                 if p.callback is not None:
                 if p.callback is not None:

+                    log.debug(u'ProcessManager.sigchild_handler: '
+                                  u'calling %s(%s)', p.callback.__name__, p)

                     p.callback(self, p)
                     p.callback(self, p)

-                if p.dont_run or not p.persist or p.error_count >= p.max_errors:
+                if (p._dont_run or not p.persist
+                                or p._error_count >= p.max_errors):
+                    log.debug(u"ProcessManager.sigchild_handler: can't "
+                            u'persist, dont_run=%s, persist=%s, error_cout=%s, '
+                            u'max_errors=%s', p._dont_run, p.persist,
+                            p._error_count, p.max_errors)

                     del self.namemap[p.name]
                     del self.pidmap[pid]
                     p.clear()
                 else:
                     del self.namemap[p.name]
                     del self.pidmap[pid]
                     p.clear()
                 else:

+                    log.debug(u'ProcessManager.sigchild_handler: persist')

                     if p.process.returncode == 0:
                     if p.process.returncode == 0:

-                        p.error_count = 0
+                        p._error_count = 0
+                        log.debug(u'ProcessManager.sigchild_handler: '
+                                u'return OK, resetting error_count')

                     else:
                     else:

-                        p.error_count += 1
+                        p._error_count += 1
+                        log.debug(u'ProcessManager.sigchild_handler: return'
+                                u'not 0, error_count + 1 = %s', p._error_count)

                     del self.pidmap[pid]
                     p.restart()
                     self.pidmap[p.process.pid] = p
                     del self.pidmap[pid]
                     p.restart()
                     self.pidmap[p.process.pid] = p


@@ -119,7 +216,7 @@ class ProcessManager:
                     return
                 raise
 
                     return
                 raise
 

-    def __getitem__(self, name):
+    def get(self, name):

         if isinstance(name, basestring): # is a name
             if name in self.namemap:
                 return self.namemap[name]
         if isinstance(name, basestring): # is a name
             if name in self.namemap:
                 return self.namemap[name]


@@ -128,9 +225,11 @@ class ProcessManager:
         else: # is a pid
             if name in self.pidmap:
                 return self.pidmap[name]
         else: # is a pid
             if name in self.pidmap:
                 return self.pidmap[name]

-        return KeyError, name
+        raise KeyError, name
+    # Syntax sugar for self[name]
+    __getitem__ = get

 
 

-    def __contains__(self, name):
+    def has(self, name):

         if isinstance(name, basestring): # is a name
             if name in self.namemap:
                 return True
         if isinstance(name, basestring): # is a name
             if name in self.namemap:
                 return True


@@ -140,6 +239,30 @@ class ProcessManager:
             if name in self.pidmap:
                 return True
         return False
             if name in self.pidmap:
                 return True
         return False

+    # Syntax sugar for name in self
+    __contains__ = has
+
+
+if __name__ == '__main__':
+    logging.basicConfig(
+        level   = logging.DEBUG,
+        format  = '%(asctime)s %(levelname)-8s %(message)s',
+        datefmt = '%H:%M:%S',
+    )
+
+
+# Globals
+manager = ProcessManager()
+register = manager.register
+unregister = manager.unregister
+once = manager.once
+start = manager.start
+stop = manager.stop
+restart = manager.restart
+kill = manager.kill
+get = manager.get
+has = manager.has
+sigchild_handler = manager.sigchild_handler

 
 
 if __name__ == '__main__':
 
 
 if __name__ == '__main__':


@@ -150,7 +273,7 @@ if __name__ == '__main__':
     sig = None
     count = 0
 
     sig = None
     count = 0
 

-    def sigchild_handler(signum, stacktrace):
+    def SIGCHLD_handler(signum, stacktrace):

         global sig
         sig = signum
         print 'SIGCHLD', signum
         global sig
         sig = signum
         print 'SIGCHLD', signum


@@ -161,26 +284,72 @@ if __name__ == '__main__':
             print 'test-service count =', count
             count += 1
             if count > 4:
             print 'test-service count =', count
             count += 1
             if count > 4:

-                print 'test-service not persistent anymore, start test2'
+                print 'set test-service non-persistent, start test-service-2'

                 pi.persist = False
                 pi.persist = False

-                pm.start('test2')
+                assert 'test-service-2' not in manager.namemap
+                pm.start('test-service-2')
+                assert 'test-service-2' in manager.namemap
+                assert get('test-service-2').running

         print 'died:', pi.name, pi.command
 
         print 'died:', pi.name, pi.command
 

-    procman = ProcessManager()
+    register('test-service', ('sleep', '2'), notify, True)
+    assert 'test-service' in manager.services
+    assert 'test-service' not in manager.namemap
+    assert not get('test-service').running
+    assert manager['test-service'] == get('test-service')
+    assert has('test-service')
+    assert 'test-service' in manager
+
+    register('test-service-2', ('sleep', '3'), notify, False)
+    assert 'test-service-2' in manager.services
+    assert 'test-service-2' not in manager.namemap
+    assert not get('test-service-2').running

 
 

-    procman.register('test-service', ('sleep', '2'), notify, True)
-    procman.register('test2', ('sleep', '3'), notify, False)
+    signal.signal(signal.SIGCHLD, SIGCHLD_handler)

 
 

-    signal.signal(signal.SIGCHLD, sigchild_handler)
+    once('test-once', ('sleep', '5'), notify)
+    assert 'test-once' not in manager.services
+    assert 'test-once' in manager.namemap
+    assert get('test-once').running
+    assert get('test-once').process.pid
+    pid = get('test-once').process.pid
+    restart('test-once')
+    assert pid != get('test-once').process.pid
+    assert pid != manager.pidmap[get('test-once').process.pid].process.pid

 
 

-    procman.call('test', ('sleep', '5'), notify)
-    procman.start('test-service')
+    start('test-service')
+    assert 'test-service' in manager.namemap
+    assert get('test-service').running
+    assert get('test-service').process.pid
+    pid = get('test-service').process.pid
+    restart('test-service')
+    assert pid != get('test-service').process.pid
+    assert pid != manager.pidmap[get('test-service').process.pid].process.pid

 
 

-    print "Esperando...", [pi.name for pi in procman.namemap.values()]
-    while procman.pidmap:
+    print "Known processes:", manager.services.keys()
+    print "Waiting...", manager.namemap.keys()
+    print "------------------------------------------------------------------"
+    while manager.pidmap:

         signal.pause()
         if sig == signal.SIGCHLD:
         signal.pause()
         if sig == signal.SIGCHLD:

+            sigchild_handler(sig)

             sig = None
             sig = None

-            procman.sigchild_handler(sig)
-        print "Esperando...", [pi.name for pi in procman.namemap.values()]
+        print "Known processes:", manager.services.keys()
+        print "Waiting...", manager.namemap.keys()
+        print "------------------------------------------------------------------"
+    assert 'test-service' not in manager.namemap
+    assert 'test-service-2' not in manager.namemap
+    assert 'test-once' not in manager.services
+    assert 'test-once' not in manager.namemap
+
+    restart('test-service')
+    assert get('test-service').process.pid
+    assert manager.pidmap[get('test-service').process.pid].process.pid
+
+    once('test-wait', ('sleep', '2'))
+    print 'test-wait running?', get('test-wait').running
+    assert get('test-wait').running
+    print 'Waiting test-wait to return...'
+    ret = get('test-wait').process.wait()
+    print 'Done! returned:', ret