CHOP-661: Fix HTTPServer usage to turn off allow_reuse_address.

Turns out that BaseHTTPServer.HTTPServer turns on that flag by default, which
causes freeport() to fail (on Windows only?), happily instantiating multiple
servers on the same port. Change known instances, fix freeport() docstring to
highlight the issue. Add freeport() unit tests to verify expected behavior.
master
Nat Goodspeed 2011-07-07 22:21:59 -04:00
parent 66dcc72870
commit 43616131dc
2 changed files with 105 additions and 4 deletions

View File

@ -124,14 +124,19 @@ class TestHTTPRequestHandler(BaseHTTPRequestHandler):
# Suppress error output as well
pass
class Server(HTTPServer):
# This pernicious flag is on by default in HTTPServer. But proper
# operation of freeport() absolutely depends on it being off.
allow_reuse_address = False
if __name__ == "__main__":
# Instantiate an HTTPServer(TestHTTPRequestHandler) on the first free port
# Instantiate a Server(TestHTTPRequestHandler) on the first free port
# in the specified port range. Doing this inline is better than in a
# daemon thread: if it blows up here, we'll get a traceback. If it blew up
# in some other thread, the traceback would get eaten and we'd run the
# subject test program anyway.
httpd, port = freeport(xrange(8000, 8020),
lambda port: HTTPServer(('127.0.0.1', port), TestHTTPRequestHandler))
lambda port: Server(('127.0.0.1', port), TestHTTPRequestHandler))
# Pass the selected port number to the subject test program via the
# environment. We don't want to impose requirements on the test program's
# command-line parsing -- and anyway, for C++ integration tests, that's

View File

@ -27,6 +27,8 @@ Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
$/LicenseInfo$
"""
from __future__ import with_statement
import os
import sys
import re
@ -79,9 +81,14 @@ def freeport(portlist, expr):
Example:
class Server(HTTPServer):
# If you use BaseHTTPServer.HTTPServer, turning off this flag is
# essential for proper operation of freeport()!
allow_reuse_address = False
# ...
server, port = freeport(xrange(8000, 8010),
lambda port: HTTPServer(("localhost", port),
MyRequestHandler))
lambda port: Server(("localhost", port),
MyRequestHandler))
# pass 'port' to client code
# call server.serve_forever()
"""
@ -164,3 +171,92 @@ def run(*args, **kwds):
rc = os.spawnv(os.P_WAIT, args[0], args)
debug("%s returned %s", args[0], rc)
return rc
# ****************************************************************************
# test code -- manual at this point, see SWAT-564
# ****************************************************************************
def test_freeport():
# ------------------------------- Helpers --------------------------------
from contextlib import contextmanager
# helper Context Manager for expecting an exception
# with exc(SomeError):
# raise SomeError()
# raises AssertionError otherwise.
@contextmanager
def exc(exception_class, *args):
try:
yield
except exception_class, err:
for i, expected_arg in enumerate(args):
assert expected_arg == err.args[i], \
"Raised %s, but args[%s] is %r instead of %r" % \
(err.__class__.__name__, i, err.args[i], expected_arg)
print "Caught expected exception %s(%s)" % \
(err.__class__.__name__, ', '.join(repr(arg) for arg in err.args))
else:
assert False, "Failed to raise " + exception_class.__class__.__name__
# helper to raise specified exception
def raiser(exception):
raise exception
# the usual
def assert_equals(a, b):
assert a == b, "%r != %r" % (a, b)
# ------------------------ Sanity check the above ------------------------
class SomeError(Exception): pass
# Without extra args, accept any err.args value
with exc(SomeError):
raiser(SomeError("abc"))
# With extra args, accept only the specified value
with exc(SomeError, "abc"):
raiser(SomeError("abc"))
with exc(AssertionError):
with exc(SomeError, "abc"):
raiser(SomeError("def"))
with exc(AssertionError):
with exc(socket.error, errno.EADDRINUSE):
raiser(socket.error(errno.ECONNREFUSED, 'Connection refused'))
# ----------- freeport() without engaging socket functionality -----------
# If portlist is empty, freeport() raises StopIteration.
with exc(StopIteration):
freeport([], None)
assert_equals(freeport([17], str), ("17", 17))
# This is the magic exception that should prompt us to retry
inuse = socket.error(errno.EADDRINUSE, 'Address already in use')
# Get the iterator to our ports list so we can check later if we've used all
ports = iter(xrange(5))
with exc(socket.error, errno.EADDRINUSE):
freeport(ports, lambda port: raiser(inuse))
# did we entirely exhaust 'ports'?
with exc(StopIteration):
ports.next()
ports = iter(xrange(2))
# Any exception but EADDRINUSE should quit immediately
with exc(SomeError):
freeport(ports, lambda port: raiser(SomeError()))
assert_equals(ports.next(), 1)
# ----------- freeport() with platform-dependent socket stuff ------------
# This is what we should've had unit tests to begin with (see CHOP-661).
def newbind(port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(('127.0.0.1', port))
return sock
bound0, port0 = freeport(xrange(7777, 7780), newbind)
assert_equals(port0, 7777)
bound1, port1 = freeport(xrange(7777, 7780), newbind)
assert_equals(port1, 7778)
bound2, port2 = freeport(xrange(7777, 7780), newbind)
assert_equals(port2, 7779)
with exc(socket.error, errno.EADDRINUSE):
bound3, port3 = freeport(xrange(7777, 7780), newbind)
if __name__ == "__main__":
test_freeport()