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