python3/ashd/serve.py

   1 import sys, os, threading, time, logging, select
   2 from . import perf
   3
   4 log = logging.getLogger("ashd.serve")
   5 seq = 1
   6 seqlk = threading.Lock()
   7
   8 def reqseq():
   9     global seq
  10     with seqlk:
  11         s = seq
  12         seq += 1
  13         return s
  14
  15 class closed(IOError):
  16     def __init__(self):
  17         super().__init__("The client has closed the connection.")
  18
  19 class reqthread(threading.Thread):
  20     def __init__(self, *, name=None, **kw):
  21         if name is None:
  22             name = "Request handler %i" % reqseq()
  23         super().__init__(name=name, **kw)
  24
  25 class wsgirequest(object):
  26     def __init__(self, handler):
  27         self.status = None
  28         self.headers = []
  29         self.respsent = False
  30         self.handler = handler
  31         self.buffer = bytearray()
  32
  33     def handlewsgi(self):
  34         raise Exception()
  35     def fileno(self):
  36         raise Exception()
  37     def writehead(self, status, headers):
  38         raise Exception()
  39     def flush(self):
  40         raise Exception()
  41     def close(self):
  42         pass
  43     def writedata(self, data):
  44         self.buffer.extend(data)
  45
  46     def flushreq(self):
  47         if not self.respsent:
  48             if not self.status:
  49                 raise Exception("Cannot send response body before starting response.")
  50             self.respsent = True
  51             self.writehead(self.status, self.headers)
  52
  53     def write(self, data):
  54         if not data:
  55             return
  56         self.flushreq()
  57         self.writedata(data)
  58         self.handler.ckflush(self)
  59
  60     def startreq(self, status, headers, exc_info=None):
  61         if self.status:
  62             if exc_info:
  63                 try:
  64                     if self.respsent:
  65                         raise exc_info[1]
  66                 finally:
  67                     exc_info = None
  68             else:
  69                 raise Exception("Can only start responding once.")
  70         self.status = status
  71         self.headers = headers
  72         return self.write
  73
  74 class handler(object):
  75     def handle(self, request):
  76         raise Exception()
  77     def ckflush(self, req):
  78         raise Exception()
  79     def close(self):
  80         pass
  81
  82     @classmethod
  83     def parseargs(cls, **args):
  84         if len(args) > 0:
  85             raise ValueError("unknown handler argument: " + next(iter(args)))
  86         return {}
  87
  88 class freethread(handler):
  89     def __init__(self, *, max=None, timeout=None, **kw):
  90         super().__init__(**kw)
  91         self.current = set()
  92         self.lk = threading.Lock()
  93         self.tcond = threading.Condition(self.lk)
  94         self.max = max
  95         self.timeout = timeout
  96
  97     @classmethod
  98     def parseargs(cls, *, max=None, abort=None, **args):
  99         ret = super().parseargs(**args)
 100         if max:
 101             ret["max"] = int(max)
 102         if abort:
 103             ret["timeout"] = int(abort)
 104         return ret
 105
 106     def handle(self, req):
 107         with self.lk:
 108             if self.max is not None:
 109                 if self.timeout is not None:
 110                     now = start = time.time()
 111                     while len(self.current) >= self.max:
 112                         self.tcond.wait(start + self.timeout - now)
 113                         now = time.time()
 114                         if now - start > self.timeout:
 115                             os.abort()
 116                 else:
 117                     while len(self.current) >= self.max:
 118                         self.tcond.wait()
 119             th = reqthread(target=self.run, args=[req])
 120             th.start()
 121             while th.is_alive() and th not in self.current:
 122                 self.tcond.wait()
 123
 124     def ckflush(self, req):
 125         while len(req.buffer) > 0:
 126             rls, wls, els = select.select([], [req], [req])
 127             req.flush()
 128
 129     def run(self, req):
 130         try:
 131             th = threading.current_thread()
 132             with self.lk:
 133                 self.current.add(th)
 134                 self.tcond.notify_all()
 135             try:
 136                 env = req.mkenv()
 137                 with perf.request(env) as reqevent:
 138                     respiter = req.handlewsgi(env, req.startreq)
 139                     for data in respiter:
 140                         req.write(data)
 141                     if req.status:
 142                         reqevent.response([req.status, req.headers])
 143                         req.flushreq()
 144                     self.ckflush(req)
 145             except closed:
 146                 pass
 147             except:
 148                 log.error("exception occurred when handling request", exc_info=True)
 149             finally:
 150                 with self.lk:
 151                     self.current.remove(th)
 152                     self.tcond.notify_all()
 153         finally:
 154             req.close()
 155
 156     def close(self):
 157         while True:
 158             with self.lk:
 159                 if len(self.current) > 0:
 160                     th = next(iter(self.current))
 161                 else:
 162                     return
 163             th.join()
 164
 165 class threadpool(handler):
 166     def __init__(self, *, min=0, max=20, live=300, **kw):
 167         super().__init__(**kw)
 168         self.current = set()
 169         self.free = set()
 170         self.lk = threading.RLock()
 171         self.pcond = threading.Condition(self.lk)
 172         self.rcond = threading.Condition(self.lk)
 173         self.wreq = None
 174         self.min = min
 175         self.max = max
 176         self.live = live
 177         for i in range(self.min):
 178             self.newthread()
 179
 180     @classmethod
 181     def parseargs(cls, *, min=None, max=None, live=None, **args):
 182         ret = super().parseargs(**args)
 183         if min:
 184             ret["min"] = int(min)
 185         if max:
 186             ret["max"] = int(max)
 187         if live:
 188             ret["live"] = int(live)
 189         return ret
 190
 191     def newthread(self):
 192         with self.lk:
 193             th = reqthread(target=self.loop)
 194             th.start()
 195             while not th in self.current:
 196                 self.pcond.wait()
 197
 198     def ckflush(self, req):
 199         while len(req.buffer) > 0:
 200             rls, wls, els = select.select([], [req], [req])
 201             req.flush()
 202
 203     def _handle(self, req):
 204         try:
 205             env = req.mkenv()
 206             with perf.request(env) as reqevent:
 207                 respiter = req.handlewsgi(env, req.startreq)
 208                 for data in respiter:
 209                     req.write(data)
 210                 if req.status:
 211                     reqevent.response([req.status, req.headers])
 212                     req.flushreq()
 213                 self.ckflush(req)
 214         except closed:
 215             pass
 216         except:
 217             log.error("exception occurred when handling request", exc_info=True)
 218         finally:
 219             req.close()
 220
 221     def loop(self):
 222         th = threading.current_thread()
 223         with self.lk:
 224             self.current.add(th)
 225         try:
 226             while True:
 227                 with self.lk:
 228                     self.free.add(th)
 229                     try:
 230                         self.pcond.notify_all()
 231                         now = start = time.time()
 232                         while self.wreq is None:
 233                             self.rcond.wait(start + self.live - now)
 234                             now = time.time()
 235                             if now - start > self.live:
 236                                 if len(self.current) > self.min:
 237                                     self.current.remove(th)
 238                                     return
 239                                 else:
 240                                     start = now
 241                         req, self.wreq = self.wreq, None
 242                         self.pcond.notify_all()
 243                     finally:
 244                         self.free.remove(th)
 245                 self._handle(req)
 246                 req = None
 247         finally:
 248             with self.lk:
 249                 try:
 250                     self.current.remove(th)
 251                 except KeyError:
 252                     pass
 253                 self.pcond.notify_all()
 254
 255     def handle(self, req):
 256         while True:
 257             with self.lk:
 258                 if len(self.free) < 1 and len(self.current) < self.max:
 259                     self.newthread()
 260                 while self.wreq is not None:
 261                     self.pcond.wait()
 262                 if self.wreq is None:
 263                     self.wreq = req
 264                     self.rcond.notify(1)
 265                     return
 266
 267     def close(self):
 268         self.live = 0
 269         self.min = 0
 270         with self.lk:
 271             while len(self.current) > 0:
 272                 self.rcond.notify_all()
 273                 self.pcond.wait(1)
 274
 275 names = {"free": freethread,
 276          "pool": threadpool}
 277
 278 def parsehspec(spec):
 279     if ":" not in spec:
 280         return spec, {}
 281     nm, spec = spec.split(":", 1)
 282     args = {}
 283     while spec:
 284         if "," in spec:
 285             part, spec = spec.split(",", 1)
 286         else:
 287             part, spec = spec, None
 288         if "=" in part:
 289             key, val = part.split("=", 1)
 290         else:
 291             key, val = part, ""
 292         args[key] = val
 293     return nm, args