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, **kw):
  90         super().__init__(**kw)
  91         self.current = set()
  92         self.lk = threading.Lock()
  93
  94     def handle(self, req):
  95         reqthread(target=self.run, args=[req]).start()
  96
  97     def ckflush(self, req):
  98         while len(req.buffer) > 0:
  99             rls, wls, els = select.select([], [req], [req])
 100             req.flush()
 101
 102     def run(self, req):
 103         try:
 104             th = threading.current_thread()
 105             with self.lk:
 106                 self.current.add(th)
 107             try:
 108                 env = req.mkenv()
 109                 with perf.request(env) as reqevent:
 110                     respiter = req.handlewsgi(env, req.startreq)
 111                     for data in respiter:
 112                         req.write(data)
 113                     if req.status:
 114                         reqevent.response([req.status, req.headers])
 115                         req.flushreq()
 116                     self.ckflush(req)
 117             except closed:
 118                 pass
 119             except:
 120                 log.error("exception occurred when handling request", exc_info=True)
 121             finally:
 122                 with self.lk:
 123                     self.current.remove(th)
 124         finally:
 125             req.close()
 126
 127     def close(self):
 128         while True:
 129             with self.lk:
 130                 if len(self.current) > 0:
 131                     th = next(iter(self.current))
 132                 else:
 133                     return
 134             th.join()
 135
 136 class threadpool(handler):
 137     def __init__(self, *, min=0, max=20, live=300, **kw):
 138         super().__init__(**kw)
 139         self.current = set()
 140         self.free = set()
 141         self.lk = threading.RLock()
 142         self.pcond = threading.Condition(self.lk)
 143         self.rcond = threading.Condition(self.lk)
 144         self.wreq = None
 145         self.min = min
 146         self.max = max
 147         self.live = live
 148         for i in range(self.min):
 149             self.newthread()
 150
 151     @classmethod
 152     def parseargs(cls, *, min=None, max=None, live=None, **args):
 153         ret = super().parseargs(**args)
 154         if min:
 155             ret["min"] = int(min)
 156         if max:
 157             ret["max"] = int(max)
 158         if live:
 159             ret["live"] = int(live)
 160         return ret
 161
 162     def newthread(self):
 163         with self.lk:
 164             th = reqthread(target=self.loop)
 165             th.start()
 166             while not th in self.current:
 167                 self.pcond.wait()
 168
 169     def ckflush(self, req):
 170         while len(req.buffer) > 0:
 171             rls, wls, els = select.select([], [req], [req])
 172             req.flush()
 173
 174     def _handle(self, req):
 175         try:
 176             env = req.mkenv()
 177             with perf.request(env) as reqevent:
 178                 respiter = req.handlewsgi(env, req.startreq)
 179                 for data in respiter:
 180                     req.write(data)
 181                 if req.status:
 182                     reqevent.response([req.status, req.headers])
 183                     req.flushreq()
 184                 self.ckflush(req)
 185         except closed:
 186             pass
 187         except:
 188             log.error("exception occurred when handling request", exc_info=True)
 189         finally:
 190             req.close()
 191
 192     def loop(self):
 193         th = threading.current_thread()
 194         with self.lk:
 195             self.current.add(th)
 196         try:
 197             while True:
 198                 with self.lk:
 199                     self.free.add(th)
 200                     try:
 201                         self.pcond.notify_all()
 202                         now = start = time.time()
 203                         while self.wreq is None:
 204                             self.rcond.wait(start + self.live - now)
 205                             now = time.time()
 206                             if now - start > self.live:
 207                                 if len(self.current) > self.min:
 208                                     self.current.remove(th)
 209                                     return
 210                                 else:
 211                                     start = now
 212                         req, self.wreq = self.wreq, None
 213                         self.pcond.notify_all()
 214                     finally:
 215                         self.free.remove(th)
 216                 self._handle(req)
 217                 req = None
 218         finally:
 219             with self.lk:
 220                 try:
 221                     self.current.remove(th)
 222                 except KeyError:
 223                     pass
 224                 self.pcond.notify_all()
 225
 226     def handle(self, req):
 227         while True:
 228             with self.lk:
 229                 if len(self.free) < 1 and len(self.current) < self.max:
 230                     self.newthread()
 231                 while self.wreq is not None:
 232                     self.pcond.wait()
 233                 if self.wreq is None:
 234                     self.wreq = req
 235                     self.rcond.notify(1)
 236                     return
 237
 238     def close(self):
 239         self.live = 0
 240         self.min = 0
 241         with self.lk:
 242             while len(self.current) > 0:
 243                 self.rcond.notify_all()
 244                 self.pcond.wait(1)
 245
 246 names = {"free": freethread,
 247          "pool": threadpool}
 248
 249 def parsehspec(spec):
 250     if ":" not in spec:
 251         return spec, {}
 252     nm, spec = spec.split(":", 1)
 253     args = {}
 254     while spec:
 255         if "," in spec:
 256             part, spec = spec.split(",", 1)
 257         else:
 258             part, spec = spec, None
 259         if "=" in part:
 260             key, val = part.split("=", 1)
 261         else:
 262             key, val = part, ""
 263         args[key] = val
 264     return nm, args