"""
This module defines `AutoReloadingAppServer`, a replacement for `AppServer`
that adds a file-monitoring and restarting to the AppServer. It's used
mostly like::
from AutoReloadingAppServer import AutoReloadingAppServer as AppServer
Much of the actually polling and monitoring takes place in the
`WebKit.ImportSpy` module.
"""
from AppServer import AppServer
import os
from threading import Thread
import time
import sys
import select
try:
True, False
except NameError:
True, False = 1, 0
try:
import _fam
haveFam = True
except:
haveFam = False
import ImportSpy
standardLibraryPrefix = '%s/lib/python%i.%i' % \
(sys.prefix, sys.version_info[0], sys.version_info[1])
DefaultConfig = {
'AutoReload': False,
'AutoReloadPollInterval': 1,
}
class AutoReloadingAppServer(AppServer):
"""AppServer AutoReloading.
This class adds functionality to `AppServer`, to notice changes to
source files, including servlets, PSPs, templates or changes to the
Webware source file themselves, and reload the server as necessary
to pick up the changes.
The server will also be restarted if a file which Webware *tried*
to import is modified. This is so that changes to a file containing
a syntax error (which would have prevented it from being imported)
will also cause the server to restart.
"""
def __init__(self,path=None):
"""Activate AutoReloading."""
AppServer.__init__(self,path)
self._autoReload = False
self._shouldRestart = False
self._requests = []
self._pipe = None
if self.isPersistent():
if self.setting('AutoReload'):
self.activateAutoReload()
def defaultConfig(self):
"""Return the default configuration."""
conf = AppServer.defaultConfig(self)
conf.update(DefaultConfig)
return conf
def shutDown(self):
"""Shut down the monitoring thread.
This is done in addition to the normal shutdown procedure.
"""
print 'Stopping AutoReload Monitor...'
sys.stdout.flush()
self.running = 1
self.deactivateAutoReload()
AppServer.shutDown(self)
sys.stdout.flush()
sys.stderr.flush()
self.running = 0
def activateAutoReload(self):
"""Start the monitor thread.W"""
ImportSpy.modloader.activate()
if not self._autoReload:
if haveFam:
print 'AutoReload Monitor started, using FAM.'
self._fileMonitorThread = t = Thread(
target=self.fileMonitorThreadLoopFAM)
else:
print 'AutoReload Monitor started, polling every', \
self.setting('AutoReloadPollInterval'), 'seconds.'
self._fileMonitorThread = t = Thread(
target=self.fileMonitorThreadLoop)
self._autoReload = True
t.setName('AutoReloadMonitor')
t.start()
def deactivateAutoReload(self):
"""Tell the monitor thread to stop.
This should be considered as a request, not a demand.
"""
self._autoReload = False
if haveFam:
self._pipe[1].write('close')
self._pipe[1].flush()
try:
self._fileMonitorThread.join()
except:
pass
def restartIfNecessary(self):
"""Check if the app server should be restarted.
This should be called regularly to see if a restart is required.
The server can only restart from the main thread, other threads
can't do the restart. So this polls to see if `shouldRestart`
has been called.
"""
if self._shouldRestart:
self.restart()
def restart(self):
"""Do the actual restart.
Call `shouldRestart` from outside the class.
"""
sys.stdout.flush()
sys.stderr.flush()
sys.exit(3)
def monitorNewModule(self, filepath, mtime):
"""Add new file to be monitored.
This is a callback which ImportSpy invokes to notify us of new files
to monitor. This is only used when we are using FAM.
"""
self._requests.append(self._fc.monitorFile(filepath, filepath) )
def shouldRestart(self):
"""Tell the main thread to restart the server."""
self._shouldRestart = True
def fileMonitorThreadLoop(self):
"""This the the main loop for the monitoring thread.
Runs in its own thread, polling the files for changes directly
(i.e., going through every file that's being used and checking
its last-modified time, seeing if it's been changed since it
was initially loaded).
"""
pollInterval = self.setting('AutoReloadPollInterval')
while self._autoReload:
time.sleep(pollInterval)
for f, mtime in ImportSpy.modloader.fileList().items():
if self.fileUpdated(f, mtime):
print '*** The file', f, 'has changed.'
print
print 'The AppServer is restarting now...'
self._autoReload = False
return self.shouldRestart()
print 'Autoreload Monitor stopped.'
sys.stdout.flush()
def fileUpdated(self, filename, mtime, getmtime=os.path.getmtime):
"""Check whether a file has been updated.
Checks if a file has been updated in such a way that we should
restart the server.
"""
try:
if mtime < getmtime(filename):
for name, mod in sys.modules.items():
if getattr(mod, '__file__', None) == filename:
break
else:
return True
if getattr(mod, '__donotreload__', None):
ImportSpy.modloader.fileList()[filename] = getmtime(filename)
return False
return True
else:
return False
except OSError:
return True
def fileMonitorThreadLoopFAM(self, getmtime=os.path.getmtime):
"""Monitoring thread loop, but using the FAM library."""
ImportSpy.modloader.notifyOfNewFiles(self.monitorNewModule)
self._fc = fc = _fam.open()
for f, mtime in ImportSpy.modloader.fileList().items():
if self.fileUpdated(f, mtime):
print '*** The file', f, 'has changed.', \
'The server is restarting now.'
self._autoReload = False
return self.shouldRestart()
self._requests.append( fc.monitorFile(f, f) )
r,w = os.pipe()
r = os.fdopen(r, 'r')
w = os.fdopen(w, 'w')
self._pipe = pipe = (r, w)
while self._autoReload:
try:
ri, ro, re = select.select([fc,pipe[0]], [], [])
except select.error, er:
errnumber, strerr = er
if errnumber == errno.EINTR:
continue
else:
print strerr
sys.exit(1)
while fc.pending():
fe = fc.nextEvent()
if (fe.code2str() in ['changed','deleted','created']
and self.fileUpdated(fe.userData,
ImportSpy.modloader.fileList()[fe.userData])):
print '*** The file', fe.userData, 'has changed.', \
'The server is restarting now.'
self._autoReload = False
return self.shouldRestart()
for req in self._requests:
req.cancelMonitor()
fc.close()
print 'Autoreload Monitor stopped'
sys.stdout.flush()