def open(cls,
*addresses,
auth,
user_agent=None,
bolt_versions=None,
timeout=0):
""" Open a connection to a Bolt server. It is here that we create a
low-level socket connection and carry out version negotiation.
Following this (and assuming success) a Connection instance will be
returned. This Connection takes ownership of the underlying socket
and is subsequently responsible for managing its lifecycle.
Args:
addresses: Tuples of host and port, such as ("127.0.0.1", 7687).
auth:
user_agent:
bolt_versions:
timeout:
Returns:
A connection to the Bolt server.
Raises:
ProtocolError: if the protocol version could not be negotiated.
"""
addresses = AddressList(addresses or cls.default_address_list)
addresses.resolve()
t0 = perf_counter()
bolt_versions = cls.fix_bolt_versions(bolt_versions)
log.debug("Trying to open connection to «%s»", addresses)
errors = set()
again = True
wait = 0.1
while again:
for address in addresses:
try:
cx = cls._open_to(address, auth, user_agent, bolt_versions)
except OSError as e:
errors.add(" ".join(map(str, e.args)))
else:
if cx:
return cx
again = perf_counter() - t0 < (timeout or 0)
if again:
sleep(wait)
wait *= 2
log.error("Could not open connection to «%s» (%r)", addresses, errors)
raise OSError("Could not open connection")
def test_ipv4_only_resolution():
a = AddressList([("localhost", "http")])
a.resolve(family=AF_INET)
assert a == [('127.0.0.1', 80)]