python3/ashd/serve.py

   1 import sys, os, threading, time, logging, select, queue
   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         while len(req.buffer) > 0:
  79             rls, wls, els = select.select([], [req], [req])
  80             req.flush()
  81     def close(self):
  82         pass
  83
  84     @classmethod
  85     def parseargs(cls, **args):
  86         if len(args) > 0:
  87             raise ValueError("unknown handler argument: " + next(iter(args)))
  88         return {}
  89
  90 class single(handler):
  91     cname = "single"
  92
  93     def handle(self, req):
  94         try:
  95             env = req.mkenv()
  96             with perf.request(env) as reqevent:
  97                 respiter = req.handlewsgi(env, req.startreq)
  98                 for data in respiter:
  99                     req.write(data)
 100                 if req.status:
 101                     reqevent.response([req.status, req.headers])
 102                     req.flushreq()
 103                 self.ckflush(req)
 104         except closed:
 105             pass
 106         except:
 107             log.error("exception occurred when handling request", exc_info=True)
 108         finally:
 109             req.close()
 110
 111 def dbg(*a):
 112     f = True
 113     for o in a:
 114         if not f:
 115             sys.stderr.write(" ")
 116         sys.stderr.write(str(a))
 117         f = False
 118     sys.stderr.write("\n")
 119     sys.stderr.flush()
 120
 121 class freethread(handler):
 122     cname = "free"
 123
 124     def __init__(self, *, max=None, timeout=None, **kw):
 125         super().__init__(**kw)
 126         self.current = set()
 127         self.lk = threading.Lock()
 128         self.tcond = threading.Condition(self.lk)
 129         self.max = max
 130         self.timeout = timeout
 131
 132     @classmethod
 133     def parseargs(cls, *, max=None, abort=None, **args):
 134         ret = super().parseargs(**args)
 135         if max:
 136             ret["max"] = int(max)
 137         if abort:
 138             ret["timeout"] = int(abort)
 139         return ret
 140
 141     def handle(self, req):
 142         with self.lk:
 143             if self.max is not None:
 144                 if self.timeout is not None:
 145                     now = start = time.time()
 146                     while len(self.current) >= self.max:
 147                         self.tcond.wait(start + self.timeout - now)
 148                         now = time.time()
 149                         if now - start > self.timeout:
 150                             os.abort()
 151                 else:
 152                     while len(self.current) >= self.max:
 153                         self.tcond.wait()
 154             th = reqthread(target=self.run, args=[req])
 155             th.registered = False
 156             th.start()
 157             while not th.registered:
 158                 self.tcond.wait()
 159
 160     def run(self, req):
 161         try:
 162             th = threading.current_thread()
 163             with self.lk:
 164                 self.current.add(th)
 165                 th.registered = True
 166                 self.tcond.notify_all()
 167             try:
 168                 env = req.mkenv()
 169                 with perf.request(env) as reqevent:
 170                     respiter = req.handlewsgi(env, req.startreq)
 171                     for data in respiter:
 172                         req.write(data)
 173                     if req.status:
 174                         reqevent.response([req.status, req.headers])
 175                         req.flushreq()
 176                     self.ckflush(req)
 177             except closed:
 178                 pass
 179             except:
 180                 log.error("exception occurred when handling request", exc_info=True)
 181             finally:
 182                 with self.lk:
 183                     self.current.remove(th)
 184                     self.tcond.notify_all()
 185         finally:
 186             req.close()
 187
 188     def close(self):
 189         while True:
 190             with self.lk:
 191                 if len(self.current) > 0:
 192                     th = next(iter(self.current))
 193                 else:
 194                     return
 195             th.join()
 196
 197 class resplex(handler):
 198     cname = "rplex"
 199
 200     def __init__(self, *, max=None, **kw):
 201         super().__init__(**kw)
 202         self.current = set()
 203         self.lk = threading.Lock()
 204         self.tcond = threading.Condition(self.lk)
 205         self.max = max
 206         self.cqueue = queue.Queue(5)
 207         self.cnpipe = os.pipe()
 208         self.rthread = reqthread(name="Response thread", target=self.handle2)
 209         self.rthread.start()
 210
 211     @classmethod
 212     def parseargs(cls, *, max=None, **args):
 213         ret = super().parseargs(**args)
 214         if max:
 215             ret["max"] = int(max)
 216         return ret
 217
 218     def ckflush(self, req):
 219         raise Exception("resplex handler does not support the write() function")
 220
 221     def handle(self, req):
 222         with self.lk:
 223             if self.max is not None:
 224                 while len(self.current) >= self.max:
 225                     self.tcond.wait()
 226             th = reqthread(target=self.handle1, args=[req])
 227             th.registered = False
 228             th.start()
 229             while not th.registered:
 230                 self.tcond.wait()
 231
 232     def handle1(self, req):
 233         try:
 234             th = threading.current_thread()
 235             with self.lk:
 236                 self.current.add(th)
 237                 th.registered = True
 238                 self.tcond.notify_all()
 239             try:
 240                 env = req.mkenv()
 241                 respobj = req.handlewsgi(env, req.startreq)
 242                 respiter = iter(respobj)
 243                 if not req.status:
 244                     log.error("request handler returned without calling start_request")
 245                     if hasattr(respiter, "close"):
 246                         respiter.close()
 247                     return
 248                 else:
 249                     self.cqueue.put((req, respiter))
 250                     os.write(self.cnpipe[1], b" ")
 251                     req = None
 252             finally:
 253                 with self.lk:
 254                     self.current.remove(th)
 255                     self.tcond.notify_all()
 256         except closed:
 257             pass
 258         except:
 259             log.error("exception occurred when handling request", exc_info=True)
 260         finally:
 261             if req is not None:
 262                 req.close()
 263
 264     def handle2(self):
 265         try:
 266             rp = self.cnpipe[0]
 267             current = {}
 268
 269             def closereq(req):
 270                 respiter = current[req]
 271                 try:
 272                     if respiter is not None and hasattr(respiter, "close"):
 273                         respiter.close()
 274                 except:
 275                     log.error("exception occurred when closing iterator", exc_info=True)
 276                 try:
 277                     req.close()
 278                 except:
 279                     log.error("exception occurred when closing request", exc_info=True)
 280                 del current[req]
 281             def ckiter(req):
 282                 respiter = current[req]
 283                 if respiter is not None:
 284                     rem = False
 285                     try:
 286                         data = next(respiter)
 287                     except StopIteration:
 288                         rem = True
 289                         try:
 290                             req.flushreq()
 291                         except:
 292                             log.error("exception occurred when handling response data", exc_info=True)
 293                     except:
 294                         rem = True
 295                         log.error("exception occurred when iterating response", exc_info=True)
 296                     if not rem:
 297                         if data:
 298                             try:
 299                                 req.flushreq()
 300                                 req.writedata(data)
 301                             except:
 302                                 log.error("exception occurred when handling response data", exc_info=True)
 303                                 rem = True
 304                     if rem:
 305                         current[req] = None
 306                         try:
 307                             if hasattr(respiter, "close"):
 308                                 respiter.close()
 309                         except:
 310                             log.error("exception occurred when closing iterator", exc_info=True)
 311                         respiter = None
 312                 if respiter is None and not req.buffer:
 313                     closereq(req)
 314
 315             while True:
 316                 bufl = list(req for req in current.keys() if req.buffer)
 317                 rls, wls, els = select.select([rp], bufl, [rp] + bufl)
 318                 if rp in rls:
 319                     ret = os.read(rp, 1024)
 320                     if not ret:
 321                         os.close(rp)
 322                         return
 323                     try:
 324                         while True:
 325                             req, respiter = self.cqueue.get(False)
 326                             current[req] = respiter
 327                             ckiter(req)
 328                     except queue.Empty:
 329                         pass
 330                 for req in wls:
 331                     try:
 332                         req.flush()
 333                     except closed:
 334                         closereq(req)
 335                     except:
 336                         log.error("exception occurred when writing response", exc_info=True)
 337                         closereq(req)
 338                     else:
 339                         if len(req.buffer) < 65536:
 340                             ckiter(req)
 341         except:
 342             log.critical("unexpected exception occurred in response handler thread", exc_info=True)
 343             os.abort()
 344
 345     def close(self):
 346         while True:
 347             with self.lk:
 348                 if len(self.current) > 0:
 349                     th = next(iter(self.current))
 350                 else:
 351                     break
 352             th.join()
 353         os.close(self.cnpipe[1])
 354         self.rthread.join()
 355
 356 names = {cls.cname: cls for cls in globals().values() if
 357          isinstance(cls, type) and
 358          issubclass(cls, handler) and
 359          hasattr(cls, "cname")}
 360
 361 def parsehspec(spec):
 362     if ":" not in spec:
 363         return spec, {}
 364     nm, spec = spec.split(":", 1)
 365     args = {}
 366     while spec:
 367         if "," in spec:
 368             part, spec = spec.split(",", 1)
 369         else:
 370             part, spec = spec, None
 371         if "=" in part:
 372             key, val = part.split("=", 1)
 373         else:
 374             key, val = part, ""
 375         args[key] = val
 376     return nm, args