def get_preferred_ip(base_bind, user_prefs):
""" Given user preferences, iterate over all address in all interfaces and check if any matches what users prefer.
Note that preferences can include actual names of interfaces, not only IP or IP ranges.
"""
# First check out if the base address to bind does not already specify a concrete IP.
# If it does, then this will be the preferred one.
parsed = urlparse('https://{}'.format(base_bind))
if parsed.hostname != '0.0.0.0':
return parsed.hostname
# What is preferred
preferred = user_prefs.ip
# What actually exists in the system
current_ifaces = net_ifaces()
# Would be very weird not to have anything, even loopback, but oh well
if not current_ifaces:
return None
current_ifaces.sort()
current_addresses = [net_ifaddresses(elem).get(AF_INET) for elem in current_ifaces]
current_addresses = [[elem.get('addr').decode('utf-8') for elem in x] for x in current_addresses]
current_addresses = list(itertools.chain.from_iterable(current_addresses))
# Preferences broken out into interfacs and network ranges/IP addresses
pref_interfaces = [elem for elem in preferred if elem in net_ifaces()]
pref_networks = [to_ip_network(elem) for elem in preferred]
pref_networks = [elem for elem in pref_networks if elem]
# If users prefer a named interface and we have it then we need to return its IP
for elem in pref_interfaces:
# If any named interface is found, returns its first IP, if there is any
ip_list = ip_list_from_interface(elem, user_prefs.allow_loopback)
if ip_list:
return str(ip_list[0])
# No address has been found by its interface but perhaps one has been specified explicitly
# or through a network range.
for current in current_addresses:
for preferred in pref_networks:
if ip_address(current) in preferred:
return current
# Ok, still nothing, so we need to find something ourselves
loopback_ip = None
# First let's try the first non-loopback interface.
for elem in current_ifaces:
for ip in ip_list_from_interface(elem, True):
if ip.is_loopback:
loopback_ip = ip
return str(ip)
# If there is only loopback and we are allowed to use it then so be it
if user_prefs.allow_loopback:
return loopback_ip
def ip_list_from_interface(interface, allow_loopback=False):
""" Return the list of IP address for the given interface, possibly including loopback addresses
"""
addresses = []
af_inet = net_ifaddresses(interface).get(AF_INET)
if af_inet:
_addresses = [elem.get('addr') for elem in af_inet]
_addresses = [elem.decode('utf-8') for elem in _addresses if elem]
for address in _addresses:
address = ip_address(address)
if address.is_loopback and not allow_loopback:
continue
addresses.append(address)
return addresses