def from_teacher_uri(
cls,
federated_only: bool,
teacher_uri: str,
min_stake: int,
) -> 'Ursula':
hostname, port, checksum_address = parse_node_uri(uri=teacher_uri)
def __attempt(round=1, interval=10) -> Ursula:
if round > 3:
raise ConnectionRefusedError(
"Host {} Refused Connection".format(teacher_uri))
try:
teacher = cls.from_seed_and_stake_info(
seed_uri='{host}:{port}'.format(host=hostname, port=port),
federated_only=federated_only,
checksum_address=checksum_address,
minimum_stake=min_stake)
except (socket.gaierror, requests.exceptions.ConnectionError,
ConnectionRefusedError):
log = Logger(cls.__name__)
log.warn(
"Can't connect to seed node (attempt {}). Will retry in {} seconds."
.format(round, interval))
time.sleep(interval)
return __attempt(round=round + 1)
else:
return teacher
return __attempt()
def from_seed_and_stake_info(
cls,
seed_uri: str,
federated_only: bool,
minimum_stake: int = 0,
checksum_address: str = None, # TODO: Why is this unused?
network_middleware: RestMiddleware = None,
*args,
**kwargs) -> 'Ursula':
#
# WARNING: xxx Poison xxx
# Let's learn what we can about the ... "seednode".
#
if network_middleware is None:
network_middleware = RestMiddleware()
host, port, checksum_address = parse_node_uri(seed_uri)
# Fetch the hosts TLS certificate and read the common name
certificate = network_middleware.get_certificate(host=host, port=port)
real_host = certificate.subject.get_attributes_for_oid(
NameOID.COMMON_NAME)[0].value
temp_node_storage = ForgetfulNodeStorage(federated_only=federated_only)
certificate_filepath = temp_node_storage.store_node_certificate(
certificate=certificate)
# Load the host as a potential seed node
potential_seed_node = cls.from_rest_url(
host=real_host,
port=port,
network_middleware=network_middleware,
certificate_filepath=certificate_filepath,
federated_only=True,
*args,
**kwargs) # TODO: 466
potential_seed_node.certificate_filepath = certificate_filepath
if checksum_address:
# Ensure this is the specific node we expected
if not checksum_address == potential_seed_node.checksum_public_address:
template = "This seed node has a different wallet address: {} (expected {}). Are you sure this is a seednode?"
raise potential_seed_node.SuspiciousActivity(
template.format(
potential_seed_node.checksum_public_address,
checksum_address))
# Check the node's stake (optional)
if minimum_stake > 0:
# TODO: check the blockchain to verify that address has more then minimum_stake. #511
raise NotImplementedError("Stake checking is not implemented yet.")
# Verify the node's TLS certificate
try:
potential_seed_node.verify_node(
network_middleware=network_middleware,
accept_federated_only=federated_only,
certificate_filepath=certificate_filepath)
except potential_seed_node.InvalidNode:
raise # TODO: What if our seed node fails verification?
# OK - everyone get out
temp_node_storage.forget()
return potential_seed_node
