"""Threaded Application Server
The AppServer is the main process of WebKit. It handles requests for
servlets from webservers.
ThreadedAppServer uses a threaded model for handling multiple requests.
At one time there were other experimental execution models for AppServer,
but none of these were successful and have been removed.
The ThreadedAppServer/AppServer distinction is thus largely historical.
ThreadedAppServer takes the following command line arguments:
start: start the AppServer (default argument)
stop: stop the currently running Apperver
daemon: run as a daemon
ClassName.SettingName=value: change configuration settings
When started, AppServer records its pid in appserverpid.txt.
"""
from Common import *
import AppServer as AppServerModule
from AutoReloadingAppServer import AutoReloadingAppServer as AppServer
from MiscUtils.Funcs import timestamp
from marshal import dumps, loads
import os, sys
from threading import Lock, Thread, Event
import threading
import Queue
import select
import socket
import threading
import time
import errno
import traceback
from WebUtils import Funcs
debug = 0
DefaultConfig = {
'Host': '127.0.0.1',
'EnableAdapter': 1,
'AdapterPort': 8086,
'EnableMonitor': 0,
'MonitorPort': 8085,
'EnableHTTP': 1,
'HTTPPort': 8080,
'MaxServerThreads': 20,
'MinServerThreads': 5,
'StartServerThreads': 10,
}
intLength = len(dumps(int(1)))
server = None
class NotEnoughDataError(Exception):
pass
class ProtocolError(Exception):
pass
class ThreadedAppServer(AppServer):
"""Threaded Application Server.
`ThreadedAppServer` accepts incoming socket requests, spawns a
new thread or reuses an existing one, then dispatches the request
to the appropriate handler (e.g., an Adapter handler, HTTP handler,
etc., one for each protocol).
The transaction is connected directly to the socket, so that the
response is sent directly (if streaming is used, like if you call
``response.flush()``). Thus the ThreadedAppServer packages the
socket/response, rather than value being returned up the call chain.
"""
def __init__(self, path=None):
"""
Setup the AppServer, create an initial thread pool
(threads created with `spawnThread`), record the PID
in a file, and add any enabled handlers (Adapter, HTTP, Monitor).
"""
self._defaultConfig = None
try:
AppServer.__init__(self, path)
threadCount = self.setting('StartServerThreads')
self._maxServerThreads = self.setting('MaxServerThreads')
self._minServerThreads = self.setting('MinServerThreads')
self._threadPool = []
self._threadCount = 0
self._threadUseCounter = []
self._requestQueue = Queue.Queue(self._maxServerThreads * 2)
self._addr = {}
self._requestID = 0
out = sys.stdout
out.write('Creating %d threads' % threadCount)
for i in range(threadCount):
self.spawnThread()
out.write(".")
out.flush()
out.write("\n")
self._socketHandlers = {}
self._handlerCache = {}
self._sockets = {}
if self.setting('EnableAdapter'):
self.addSocketHandler(AdapterHandler)
if self.setting('EnableMonitor'):
self.addSocketHandler(MonitorHandler)
if self.setting('EnableHTTP'):
from WebKit.HTTPServer import HTTPAppServerHandler
self.addSocketHandler(HTTPAppServerHandler)
self.readyForRequests()
except:
if self.running:
self.initiateShutdown()
self._closeThread.join()
raise
def addSocketHandler(self, handlerClass, serverAddress=None):
"""Add socket handler.
Adds a socket handler for `serverAddress` -- `serverAddress`
is a tuple (*host*, *port*), where *host* is the interface
to connect to (for instance, the IP address on a machine with
multiple IP numbers), and *port* is the port (e.g. HTTP is on
80 by default, and Webware adapters use 8086 by default).
The `handlerClass` is a subclass of `Handler`, and is used to
handle the actual request -- usually returning control back
to ThreadedAppServer in some fashion. See `Handler` for more.
"""
if serverAddress is None:
serverAddress = self.address(handlerClass.settingPrefix)
self._socketHandlers[serverAddress] = handlerClass
self._handlerCache[serverAddress] = []
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
try:
sock.bind(serverAddress)
sock.listen(1024)
except:
print "Error: Can not listen for %s on %s" % (
handlerClass.settingPrefix, str(serverAddress))
sys.stdout.flush()
raise
print "Listening for %s on %s" % (
handlerClass.settingPrefix, str(serverAddress))
f = open(self.serverSidePath(
'%s.text' % handlerClass.protocolName), 'w')
f.write('%s:%d' % (serverAddress[0], serverAddress[1]))
f.close()
self._sockets[serverAddress] = sock
def isPersistent(self):
return True
def defaultConfig(self):
if self._defaultConfig is None:
self._defaultConfig = AppServer.defaultConfig(self).copy()
self._defaultConfig.update(DefaultConfig)
return self._defaultConfig
def mainloop(self, timeout=1):
"""Main thread loop.
This is the main thread loop that accepts and dispatches
socket requests.
It goes through a loop as long as ``self.running > 2``.
Setting ``self.running = 2`` asks the the main loop to end.
When the main loop is finished, it sets ``self.running = 1``.
When the AppServer is completely down, it sets ``self.running = 0``.
The loop waits for connections, then based on the connecting
port it initiates the proper Handler (e.g.,
AdapterHandler, HTTPHandler). Handlers are reused when possible.
The initiated handlers are put into a queue, and
worker threads poll that queue to look for requests that
need to be handled (worker threads use `threadloop`).
Every so often (every 5 loops) it updates thread usage
information (`updateThreadUsage`), and every
``MaxServerThreads`` * 2 loops it it will manage
threads (killing or spawning new ones, in `manageThreadCount`).
"""
threadCheckInterval = self._maxServerThreads*2
threadUpdateDivisor = 5
threadCheck = 0
self.running = 3
try:
while self.running > 2:
input, output, exc = select.select(
self._sockets.values(), [], [], timeout)
for sock in input:
self._requestID += 1
client, addr = sock.accept()
serverAddress = sock.getsockname()
try:
handler = self._handlerCache[serverAddress].pop()
except IndexError:
handler = self._socketHandlers[serverAddress](self,
serverAddress)
handler.activate(client, self._requestID)
self._requestQueue.put(handler)
if threadCheck % threadUpdateDivisor == 0:
self.updateThreadUsage()
if threadCheck > threadCheckInterval:
threadCheck = 0
self.manageThreadCount()
else:
threadCheck = threadCheck + 1
self.restartIfNecessary()
finally:
self.running = 1
def updateThreadUsage(self):
"""Update the threadUseCounter list.
Called periodically from `mainloop`.
"""
count = self.activeThreadCount()
if len(self._threadUseCounter) > self._maxServerThreads:
self._threadUseCounter.pop(0)
self._threadUseCounter.append(count)
def activeThreadCount(self):
"""Get a snapshot of the number of threads currently in use.
Called from `updateThreadUsage`.
"""
count = 0
for i in self._threadPool:
if i._processing:
count = count + 1
return count
def manageThreadCount(self):
"""Adjust the number of threads in use.
From information gleened from `updateThreadUsage`, we see about how
many threads are being used, to see if we have too many threads or
too few. Based on this we create or absorb threads.
"""
average = 0
max = 0
debug = 0
if debug: print "ThreadUse Samples=%s" % str(self._threadUseCounter)
for i in self._threadUseCounter:
average += i
if i > max:
max = i
average = average / len(self._threadUseCounter)
if debug:
print "Average Thread Use: ", avg
print "Max Thread Use: ", max
print "ThreadCount: ", self.threadCount
if len(self._threadUseCounter) < self._maxServerThreads:
return enough samples
margin = self._threadCount / 2
if debug:
print "margin=", margin
if average > self._threadCount - margin and \
self._threadCount < self._maxServerThreads:
n = min(self._threadCount,
self._maxServerThreads - self._threadCount)
if debug:
print "Adding %s threads" % n
for i in range(n):
self.spawnThread()
elif average < self._threadCount - margin and \
self._threadCount > self._minServerThreads:
n=min(self._threadCount - self._minServerThreads,
self._threadCount - max)
self.absorbThread(n)
else:
self.absorbThread(0)
def spawnThread(self):
"""Create a new worker thread.
Worker threads poll with the `threadloop` method.
"""
debug = 0
if debug:
print "Spawning new thread"
t = Thread(target=self.threadloop)
t._processing = False
t.start()
self._threadPool.append(t)
self._threadCount += 1
if debug:
print "New thread spawned, threadCount =", self._threadCount
def absorbThread(self, count=1):
"""Absorb a thread.
We do this by putting a None on the Queue.
When a thread gets it, that tells it to exit.
We also keep track of the threads, so after killing
threads we go through all the threads and find the
thread(s) that have exited, so that we can take them
out of the thread pool.
"""
for i in range(count):
self._requestQueue.put(None)
self._threadCount -= 1
for i in self._threadPool:
if not i.isAlive():
rv = i.join()
self._threadPool.remove(i)
if debug:
print "Thread absorbed, real threadCount =", len(self.threadPool)
def threadloop(self):
"""The main loop for worker threads.
Worker threads poll the ``_requestQueue`` to find a request handler
waiting to run. If they find a None in the queue, this thread has
been selected to die, which is the way the loop ends.
The handler object does all the work when its `handleRequest` method
is called.
`initThread` and `delThread` methods are called at the beginning and
end of the thread loop, but they aren't being used for anything
(future use as a hook).
"""
self.initThread()
t = threading.currentThread()
t.processing = False
try:
while 1:
try:
handler = self._requestQueue.get()
if handler is None:
if debug:
print "Thread retrieved None, quitting."
break
t.processing = True
try:
handler.handleRequest()
except:
traceback.print_exc(file=sys.stderr)
t.processing = False
handler.close()
except Queue.Empty:
pass
finally:
self.delThread()
if debug:
print threading.currentThread(), "Quitting."
def initThread(self):
"""Initialize thread.
Invoked immediately by threadloop() as a hook for subclasses.
This implementation does nothing and subclasses need not invoke super.
"""
pass
def delThread(self):
"""Delete thread.
Invoked immediately by threadloop() as a hook for subclasses.
This implementation does nothing and subclasses need not invoke super.
"""
pass
def shutDown(self):
"""Called on shutdown.
Also calls `AppServer.shutDown`, but first closes all sockets
and tells all the threads to die.
"""
if self.running > 2:
self.running = 2
print "ThreadedAppServer is shutting down..."
sys.stdout.flush()
self.awakeSelect()
for i in range(30):
if self.running < 2:
break
time.sleep(0.1)
for sock in self._sockets.values():
sock.close()
for i in range(self._threadCount):
self._requestQueue.put(None)
for i in self._threadPool:
try:
i.join()
except:
pass
AppServer.shutDown(self)
sys.stdout.flush()
sys.stderr.flush()
self.running = 0
def awakeSelect(self):
"""Awake the select() call.
The ``select()`` in `mainloop()` is blocking, so when
we shut down we have to make a connect to unblock it.
Here's where we do that, called `shutDown`.
"""
for host, port in self._sockets.keys():
if host == '0.0.0.0':
host = '127.0.0.1'
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
sock.connect((host, port))
sock.close()
except:
pass
def address(self, settingPrefix):
"""Get host address.
The address for the Adapter (Host/interface, and port),
as taken from ``Configs/AppServer.config``,
settings ``Host`` and ``AdapterPort``.
"""
try:
return self._addr[settingPrefix]
except KeyError:
host = self.setting(settingPrefix + 'Host',
self.setting('Host'))
if settingPrefix == 'Adapter':
port = self.setting('Port', None)
if port is None:
port = self.setting(settingPrefix + 'Port')
else:
print "WARNING:", \
"The 'Port' setting has been renamed to 'AdapterPort'."
print "Please update your AppServer.config file."
else:
port = self.setting(settingPrefix + 'Port')
self._addr[settingPrefix] = (
host,
port)
return self._addr[settingPrefix]
class Handler:
"""A very general socket handler.
Handler is an abstract superclass -- specific protocol implementations
will subclass this. A Handler takes a socket to interact with, and
creates a raw request.
Handlers will be reused. When a socket is received `activate` will be
called -- but the handler should not do anything, as it is still running
in the main thread. The handler is put into a queue, and a worker thread
picks it up and runs `handleRequest`, which subclasses should override.
Several methods are provided which are typically used by subclasses.
"""
def __init__(self, server, serverAddress):
"""Create a new socket handler.
Each handler is attached to a specific host and port,
and of course to the AppServer.
"""
self._server = server
self._serverAddress = serverAddress
def activate(self, sock, requestID):
"""Activate the handler for processing the request.
`sock` is the incoming socket that this handler will work with,
and `requestID` is a serial number unique for each request.
This isn't where work gets done -- the handler is queued after this,
and work is done when `handleRequest` is called.
"""
self._requestID = requestID
self._sock = sock
def close(self):
"""Close the socket.
Called when the handler is finished. Closes the socket and
returns the handler to the pool of inactive handlers.
"""
self._sock = None
self._server._handlerCache[self._serverAddress].append(self)
def handleRequest(self):
"""
Subclasses should override this -- this is where
work gets done.
"""
pass
def receiveDict(self):
"""Receive a dictionary from the socket.
Utility function to receive a marshalled dictionary from
the socket. Returns None if the request was empty.
"""
chunk = ''
missing = intLength
while missing > 0:
block = self._sock.recv(missing)
if not block:
self._sock.close()
if len(chunk) == 0:
return None
else:
raise NotEnoughDataError, 'received only %d of %d bytes' \
' when receiving dictLength' % (len(chunk), intLength)
chunk += block
missing = intLength - len(chunk)
try:
dictLength = loads(chunk)
except ValueError, msg:
if chunk[:3] == 'GET':
self._sock.sendall('''\
HTTP/1.0 505 HTTP Version Not Supported\r
Content-type: text/plain\r
\r
Error: Invalid AppServer protocol: %s.\r
Sorry, I don't speak HTTP. You must connect via an adapter.\r
See the Troubleshooting section of the WebKit Install Guide.\r
''' % msg)
self._sock.close()
return None
print 'ERROR:', msg
print 'ERROR: you can only connect to', self._serverAddress[1], \
'via an adapter,'
print ' like mod_webkit or wkcgi, not with a browser.'
raise
if type(dictLength) != type(1):
self._sock.close()
raise ProtocolError, "Invalid AppServer protocol"
chunk = ''
missing = dictLength
while missing > 0:
block = self._sock.recv(missing)
if not block:
self._sock.close()
raise NotEnoughDataError, 'received only %d of %d bytes' \
' when receiving dict' % (len(chunk), dictLength)
chunk += block
missing = dictLength - len(chunk)
return loads(chunk)
class MonitorHandler(Handler):
"""Monitor server status.
Monitor is a minimal service that accepts a simple protocol,
and returns a value indicating the status of the server.
The protocol passes a marshalled dict, much like the Adapter
interface, which looks like ``{'format': 'XXX'}``, where XXX
is a command (``STATUS`` or ``QUIT``). Responds with a simple
string, either the number of requests we've received (for
``STATUS``) or ``OK`` for ``QUIT`` (which also stops the server).
"""
protocolName = 'monitor'
settingPrefix = 'Monitor'
def handleRequest(self):
verbose = self._server._verbose
startTime = time.time()
if verbose:
print 'BEGIN REQUEST'
print time.asctime(time.localtime(startTime))
conn = self._sock
if verbose:
print 'receiving request from', conn
BUFSIZE = 8*1024
dict = self.receiveDict()
if dict['format'] == "STATUS":
conn.send(str(self._server._requestID))
elif dict['format'] == 'QUIT':
conn.send("OK")
conn.close()
self._server.shutDown()
from WebKit.ASStreamOut import ASStreamOut
class TASASStreamOut(ASStreamOut):
"""Response stream for ThreadedAppServer.
The `TASASStreamOut` class streams to a given socket, so that when `flush`
is called and the buffer is ready to be written, it sends the data from the
buffer out on the socket. This is the response stream used for requests
generated by ThreadedAppServer.
TAS stands for ThreadedAppServer (AS for AppServer... a little redundant).
"""
def __init__(self, sock):
"""Create stream.
We get an extra `sock` argument, which is the socket which we'll
stream output to (if we're streaming).
"""
ASStreamOut.__init__(self)
self._socket = sock
def flush(self):
"""Flush stream.
Calls `ASStreamOut.ASStreamOut.flush`, and if that returns True
(indicating the buffer is full enough) then we send data from
the buffer out on the socket.
"""
debug = 0
result = ASStreamOut.flush(self)
if result:
reslen = len(self._buffer)
sent = 0
while sent < reslen:
try:
sent = sent + self._socket.send(
self._buffer[sent:sent+8192])
except socket.error, e:
if e[0] == errno.EPIPE:
pass
elif hasattr(errno, 'ECONNRESET') \
and e[0] == errno.ECONNRESET:
pass
else:
print "StreamOut Error: ", e
break
self.pop(sent)
class AdapterHandler(Handler):
"""Adapter handler.
Handles the Adapter protocol (as used in mod_webkit, wkcgi,
WebKit.cgi, HTTPAdapter, etc). This protocol passes a marshalled
dictionary which contains the keys ``format`` and ``environ``.
``format`` is currently always the string ``CGI``, and ``environ``
is a dictionary of string: string, with values like those passed
in the environment to a CGI request (QUERY_STRING, HTTP_HOST, etc).
The handler adds one more key, ``input``, which contains a file
object based off the socket, which contains the body of the
request (the POST data, for instance). It's left to Application
to handle that data.
"""
protocolName = 'address'
settingPrefix = 'Adapter'
def handleRequest(self):
"""Handle request.
Creates the request dictionary, and creates a `TASASStreamOut` object
for the response, then calls `Application.dispatchRawRequest`, which
does the rest of the work (here we just clean up after).
"""
verbose = self._server._verbose
self._startTime = time.time()
data = []
dict = self.receiveDict()
if not dict:
return
if verbose:
requestURI = dict.has_key('environ') and Funcs.requestURI(dict['environ']) or None
sys.stdout.write('%5i %s %s\n' % (self._requestID, timestamp()['pretty'], requestURI))
dict['input'] = self.makeInput()
dict['requestID'] = self._requestID
streamOut = TASASStreamOut(self._sock)
transaction = self._server._app.dispatchRawRequest(dict, streamOut)
streamOut.close()
try:
self._sock.shutdown(1)
self._sock.close()
except:
pass
if verbose:
duration = '%0.2f secs' % (time.time() - self._startTime)
duration = duration.ljust(19)
sys.stdout.write('%5i %s %s\n\n' % (self._requestID, duration, requestURI))
transaction._application=None
transaction.die()
del transaction
def makeInput(self):
"""Create a file-like object from the socket."""
return self._sock.makefile("rb", 8012)
def runMainLoopInThread():
return os.name == 'nt'
doesRunHandleExceptions = True
class RestartAppServerError(Exception):
"""Raised by DebugAppServer when needed."""
pass
def run(workDir=None):
"""Start the server (`ThreadedAppServer`).
`workDir` is the server-side path for the server, which may not be
the ``Webware/WebKit`` directory (though by default it is).
After setting up the ThreadedAppServer we call `ThreadedAppServer.mainloop`
to start the server main loop. It also catches exceptions as a last resort.
"""
global server
server = None
global exitStatus
exitStatus = 0
runAgain = True
while runAgain:
try:
try:
runAgain = False
server = ThreadedAppServer(workDir)
if runMainLoopInThread():
def _windowsmainloop():
global exitStatus
try:
server.mainloop()
except SystemExit, e:
exitStatus = e[0]
t = threading.Thread(
target=_windowsmainloop)
t.start()
try:
while server.running > 1:
time.sleep(1)
finally:
t.join()
else:
server.mainloop()
sys.exit(exitStatus)
except RestartAppServerError:
print
print "Restarting AppServer:"
sys.stdout.flush()
sys.stderr.flush()
runAgain = True
except SystemExit, e:
print
print "Exiting AppServer%s." % (
e[0] == 3 and ' for reload' or '')
exitStatus = e[0]
except KeyboardInterrupt:
print
print "Exiting AppServer due to keyboard interrupt."
exitStatus = 0
except Exception, e:
if isinstance(e, IOError) and e[0] == errno.EINTR:
print
print "Exiting AppServer due to interrupt signal."
exitStatus = 0
else:
if doesRunHandleExceptions:
import traceback
print
traceback.print_exc(file=sys.stderr)
print "Exiting AppServer due to above exception."
exitStatus = 1
else:
raise
finally:
sys.stdout.flush()
sys.stderr.flush()
if server and server.running:
server.initiateShutdown()
server._closeThread.join()
AppServerModule.globalAppServer = None
sys.stdout.flush()
sys.stderr.flush()
return exitStatus
def shutDown(signum, frame):
"""Signal handler for shutting down the server."""
global server
print
print "App server has been signaled to shutdown."
if server and server.running > 2:
print "Shutting down at", time.asctime(time.localtime(time.time()))
sys.stdout.flush()
server.running = 2
if signum == SIGINT:
raise KeyboardInterrupt
elif signum == SIGHUP:
sys.exit(3)
else:
sys.exit(0)
else:
print 'No running app server was found.'
import signal
try:
SIGHUP = signal.SIGHUP
signal.signal(SIGHUP, shutDown)
except AttributeError:
SIGHUP = None
try:
SIGINT = signal.SIGINT
signal.signal(SIGINT, shutDown)
except AttributeError:
SIGINT = None
try:
SIGTERM = signal.SIGTERM
signal.signal(SIGTERM, shutDown)
except AttributeError:
SIGTERM = None
import re
settingRE = re.compile(r'^(?:--)?([a-zA-Z][a-zA-Z0-9]*\.[a-zA-Z][a-zA-Z0-9]*)=')
from MiscUtils import Configurable
usage = re.search('\n.* arguments:\n\n(.*\n)*?\n', __doc__).group(0)
def main(args):
"""Command line interface.
Run by `Launch`, this is the main entrance and command-line interface
for ThreadedAppServer.
"""
function = run
daemon = False
workDir = None
for i in args[:]:
if settingRE.match(i):
match = settingRE.match(i)
name = match.group(1)
value = i[match.end():]
Configurable.addCommandLineSetting(name, value)
elif i == "stop":
import AppServer
function = AppServer.stop
elif i == "daemon":
daemon = True
elif i == "start":
pass
elif i[:8] == "workdir=":
workDir = i[8:]
else:
print usage
return
if daemon:
if os.name == "posix":
pid = os.fork()
if pid:
sys.exit()
else:
print "Daemon mode not available on your OS."
return function(workDir=workDir)