python: Handle errors when loading chained modules more properly.

[ashd.git] / python3 / scgi-wsgi3

#!/usr/bin/python3

import sys, os, getopt
import socket
import ashd.scgi

def usage(out):
    out.write("usage: scgi-wsgi3 [-hA] [-p MODPATH] [-T [HOST:]PORT] HANDLER-MODULE [ARGS...]\n")

sk = None
modwsgi_compat = False
opts, args = getopt.getopt(sys.argv[1:], "+hAp:T:")
for o, a in opts:
    if o == "-h":
        usage(sys.stdout)
        sys.exit(0)
    elif o == "-p":
        sys.path.insert(0, a)
    elif o == "-T":
        sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        p = a.rfind(":")
        if p < 0:
            bindhost = "localhost"
            bindport = int(a)
        else:
            bindhost = a[:p]
            bindport = int(a[p + 1:])
        sk.bind((bindhost, bindport))
        sk.listen(32)
    elif o == "-A":
        modwsgi_compat = True
if len(args) < 1:
    usage(sys.stderr)
    sys.exit(1)

if sk is None:
    # This is suboptimal, since the socket on stdin is not necessarily
    # AF_UNIX, but Python does not seem to offer any way around it,
    # that I can find.
    sk = socket.fromfd(0, socket.AF_UNIX, socket.SOCK_STREAM)

try:
    handlermod = __import__(args[0], fromlist = ["dummy"])
except ImportError as exc:
    sys.stderr.write("scgi-wsgi3: handler %s not found: %s\n" % (args[0], exc.args[0]))
    sys.exit(1)
if not modwsgi_compat:
    if not hasattr(handlermod, "wmain"):
        sys.stderr.write("scgi-wsgi3: handler %s has no `wmain' function\n" % args[0])
        sys.exit(1)
    handler = handlermod.wmain(*args[1:])
else:
    if not hasattr(handlermod, "application"):
        sys.stderr.write("scgi-wsgi3: handler %s has no `application' object\n" % args[0])
        sys.exit(1)
    handler = handlermod.application

ashd.scgi.servescgi(sk, ashd.scgi.wrapwsgi(handler))