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