python/ashd-wsgi

   1 #!/usr/bin/python
   2
   3 import sys, os, getopt, threading, logging, time
   4 import ashd.proto, ashd.util, ashd.perf
   5 try:
   6     import pdm.srv
   7 except:
   8     pdm = None
   9
  10 def usage(out):
  11     out.write("usage: ashd-wsgi [-hAL] [-m PDM-SPEC] [-p MODPATH] [-l REQLIMIT] HANDLER-MODULE [ARGS...]\n")
  12
  13 reqlimit = 0
  14 modwsgi_compat = False
  15 setlog = True
  16 opts, args = getopt.getopt(sys.argv[1:], "+hAp:l:m:")
  17 for o, a in opts:
  18     if o == "-h":
  19         usage(sys.stdout)
  20         sys.exit(0)
  21     elif o == "-p":
  22         sys.path.insert(0, a)
  23     elif o == "-L":
  24         setlog = False
  25     elif o == "-A":
  26         modwsgi_compat = True
  27     elif o == "-l":
  28         reqlimit = int(a)
  29     elif o == "-m":
  30         if pdm is not None:
  31             pdm.srv.listen(a)
  32 if len(args) < 1:
  33     usage(sys.stderr)
  34     sys.exit(1)
  35 if setlog:
  36     logging.basicConfig(format="ashd-wsgi(%(name)s): %(levelname)s: %(message)s")
  37 log = logging.getLogger("ashd-wsgi")
  38
  39 try:
  40     handlermod = __import__(args[0], fromlist = ["dummy"])
  41 except ImportError, exc:
  42     sys.stderr.write("ashd-wsgi: handler %s not found: %s\n" % (args[0], exc.message))
  43     sys.exit(1)
  44 if not modwsgi_compat:
  45     if not hasattr(handlermod, "wmain"):
  46         sys.stderr.write("ashd-wsgi: handler %s has no `wmain' function\n" % args[0])
  47         sys.exit(1)
  48     handler = handlermod.wmain(*args[1:])
  49 else:
  50     if not hasattr(handlermod, "application"):
  51         sys.stderr.write("ashd-wsgi: handler %s has no `application' object\n" % args[0])
  52         sys.exit(1)
  53     handler = handlermod.application
  54
  55 class closed(IOError):
  56     def __init__(self):
  57         super(closed, self).__init__("The client has closed the connection.")
  58
  59 cwd = os.getcwd()
  60 def absolutify(path):
  61     if path[0] != '/':
  62         return os.path.join(cwd, path)
  63     return path
  64
  65 def unquoteurl(url):
  66     buf = ""
  67     i = 0
  68     while i < len(url):
  69         c = url[i]
  70         i += 1
  71         if c == '%':
  72             if len(url) >= i + 2:
  73                 c = 0
  74                 if '0' <= url[i] <= '9':
  75                     c |= (ord(url[i]) - ord('0')) << 4
  76                 elif 'a' <= url[i] <= 'f':
  77                     c |= (ord(url[i]) - ord('a') + 10) << 4
  78                 elif 'A' <= url[i] <= 'F':
  79                     c |= (ord(url[i]) - ord('A') + 10) << 4
  80                 else:
  81                     raise ValueError("Illegal URL escape character")
  82                 if '0' <= url[i + 1] <= '9':
  83                     c |= ord(url[i + 1]) - ord('0')
  84                 elif 'a' <= url[i + 1] <= 'f':
  85                     c |= ord(url[i + 1]) - ord('a') + 10
  86                 elif 'A' <= url[i + 1] <= 'F':
  87                     c |= ord(url[i + 1]) - ord('A') + 10
  88                 else:
  89                     raise ValueError("Illegal URL escape character")
  90                 buf += chr(c)
  91                 i += 2
  92             else:
  93                 raise ValueError("Incomplete URL escape character")
  94         else:
  95             buf += c
  96     return buf
  97
  98 def dowsgi(req):
  99     env = {}
 100     env["wsgi.version"] = 1, 0
 101     for key, val in req.headers:
 102         env["HTTP_" + key.upper().replace("-", "_")] = val
 103     env["SERVER_SOFTWARE"] = "ashd-wsgi/1"
 104     env["GATEWAY_INTERFACE"] = "CGI/1.1"
 105     env["SERVER_PROTOCOL"] = req.ver
 106     env["REQUEST_METHOD"] = req.method
 107     env["REQUEST_URI"] = req.url
 108     name = req.url
 109     p = name.find('?')
 110     if p >= 0:
 111         env["QUERY_STRING"] = name[p + 1:]
 112         name = name[:p]
 113     else:
 114         env["QUERY_STRING"] = ""
 115     if name[-len(req.rest):] == req.rest:
 116         # This is the same hack used in call*cgi.
 117         name = name[:-len(req.rest)]
 118     try:
 119         pi = unquoteurl(req.rest)
 120     except:
 121         pi = req.rest
 122     if name == '/':
 123         # This seems to be normal CGI behavior, but see callcgi.c for
 124         # details.
 125         pi = "/" + pi
 126         name = ""
 127     env["SCRIPT_NAME"] = name
 128     env["PATH_INFO"] = pi
 129     if "Host" in req: env["SERVER_NAME"] = req["Host"]
 130     if "X-Ash-Server-Port" in req: env["SERVER_PORT"] = req["X-Ash-Server-Port"]
 131     if "X-Ash-Protocol" in req and req["X-Ash-Protocol"] == "https": env["HTTPS"] = "on"
 132     if "X-Ash-Address" in req: env["REMOTE_ADDR"] = req["X-Ash-Address"]
 133     if "Content-Type" in req:
 134         env["CONTENT_TYPE"] = req["Content-Type"]
 135         # The CGI specification does not strictly require this, but
 136         # many actualy programs and libraries seem to.
 137         del env["HTTP_CONTENT_TYPE"]
 138     if "Content-Length" in req:
 139         env["CONTENT_LENGTH"] = req["Content-Length"]
 140         del env["HTTP_CONTENT_LENGTH"]
 141     if "X-Ash-File" in req: env["SCRIPT_FILENAME"] = absolutify(req["X-Ash-File"])
 142     if "X-Ash-Protocol" in req: env["wsgi.url_scheme"] = req["X-Ash-Protocol"]
 143     env["wsgi.input"] = req.sk
 144     env["wsgi.errors"] = sys.stderr
 145     env["wsgi.multithread"] = True
 146     env["wsgi.multiprocess"] = False
 147     env["wsgi.run_once"] = False
 148
 149     resp = []
 150     respsent = []
 151
 152     def flushreq():
 153         if not respsent:
 154             if not resp:
 155                 raise Exception, "Trying to write data before starting response."
 156             status, headers = resp
 157             respsent[:] = [True]
 158             try:
 159                 req.sk.write("HTTP/1.1 %s\n" % status)
 160                 for nm, val in headers:
 161                     req.sk.write("%s: %s\n" % (nm, val))
 162                 req.sk.write("\n")
 163             except IOError:
 164                 raise closed()
 165
 166     def write(data):
 167         if not data:
 168             return
 169         flushreq()
 170         try:
 171             req.sk.write(data)
 172             req.sk.flush()
 173         except IOError:
 174             raise closed()
 175
 176     def startreq(status, headers, exc_info = None):
 177         if resp:
 178             if exc_info:                # Interesting, this...
 179                 try:
 180                     if respsent:
 181                         raise exc_info[0], exc_info[1], exc_info[2]
 182                 finally:
 183                     exc_info = None     # CPython GC bug?
 184             else:
 185                 raise Exception, "Can only start responding once."
 186         resp[:] = status, headers
 187         return write
 188
 189     reqevent = ashd.perf.request(env)
 190     exc = (None, None, None)
 191     try:
 192         try:
 193             respiter = handler(env, startreq)
 194             try:
 195                 for data in respiter:
 196                     write(data)
 197                 if resp:
 198                     flushreq()
 199             finally:
 200                 if hasattr(respiter, "close"):
 201                     respiter.close()
 202         except closed:
 203             pass
 204         if resp:
 205             reqevent.response(resp)
 206     except:
 207         exc = sys.exc_info()
 208         raise
 209     finally:
 210         reqevent.__exit__(*exc)
 211
 212 flightlock = threading.Condition()
 213 inflight = 0
 214
 215 class reqthread(threading.Thread):
 216     def __init__(self, req):
 217         super(reqthread, self).__init__(name = "Request handler")
 218         self.req = req.dup()
 219
 220     def run(self):
 221         global inflight
 222         try:
 223             flightlock.acquire()
 224             try:
 225                 if reqlimit != 0:
 226                     start = time.time()
 227                     while inflight >= reqlimit:
 228                         flightlock.wait(10)
 229                         if time.time() - start > 10:
 230                             os.abort()
 231                 inflight += 1
 232             finally:
 233                 flightlock.release()
 234             try:
 235                 dowsgi(self.req)
 236             finally:
 237                 flightlock.acquire()
 238                 try:
 239                     inflight -= 1
 240                     flightlock.notify()
 241                 finally:
 242                     flightlock.release()
 243         except:
 244             log.error("exception occurred in handler thread", exc_info=True)
 245         finally:
 246             self.req.close()
 247
 248 def handle(req):
 249     reqthread(req).start()
 250
 251 ashd.util.serveloop(handle)