在原本稳定的环境中，当我调用cluster.connect()时，代码只是无限期地挂起，没有错误或超时消息。该连接包含在Nameko服务中。我怀疑它与Nameko服务代码有关，尤其是涉及到的猴子补丁，因为否则相同的代码在Nameko服务之外也可以正常工作。
我应该注意，这似乎仅是Python 3.7和Cassandra 3.18的问题。使用Python 3.6和Cassandra 3.16，可以正常工作。
这是一个代码段：
import logging
from cassandra import ConsistencyLevel, cluster
from nameko.extensions import DependencyProvider
from pipeline import config
class CassandraConnection(DependencyProvider):
"""
Encapsulate a cassandra session with an open connection.
"""
def __init__(self):
self._logger = logging.getLogger('cassandra_writer')
self._cluster = None
self._session = None
def setup(self):
self._cluster = cluster.Cluster(config.get('cassandra', 'node').split(','))
self._session = self._cluster.connect()
self._session.set_keyspace(config.get('cassandra', 'keyspace_ts'))
self._session.default_consistency_level = ConsistencyLevel.QUORUM
def get_dependency(self, worker_ctx):
return self._session
这是完整的启动日志：
INFO starting services: cassandra_writer
DEBUG starting <ServiceContainer [cassandra_writer] at 0x7fa5d1411b70>
DEBUG starting <ExchangeEventHandler [cassandra_writer.write_objects] at 0x7fa5bc685ba8>
DEBUG registering provider <ExchangeEventHandler [cassandra_writer.write_objects] at 0x7fa5bc685ba8> for <QueueConsumer at 0x7fa5bc685c18>
DEBUG Start from server, version: 0.9, properties: {'capabilities': {'publisher_confirms': True, 'exchange_exchange_bindings': True, 'basic.nack': True, 'consumer_cancel_notify': True, 'connection.blocked': True, 'consumer_priorities': True, 'authentication_failure_close': True, 'per_consumer_qos': True, 'direct_reply_to': True}, 'cluster_name': 'rabbit@USRMQQA03.alphanetcapital.com', 'copyright': 'Copyright (C) 2007-2019 Pivotal Software, Inc.', 'information': 'Licensed under the MPL. See http://www.rabbitmq.com/', 'platform': 'Erlang/OTP 21.2.6', 'product': 'RabbitMQ', 'version': '3.7.13'}, mechanisms: [b'AMQPLAIN', b'PLAIN'], locales: ['en_US']
WARNING Cluster.__init__ called with contact_points specified, but no load_balancing_policy. In the next major version, this will raise an error; please specify a load-balancing policy. (contact_points = ['uscstardev01', 'uscstardev02', 'uscstardev03'], lbp = None)
INFO <class 'cassandra.io.eventletreactor.EventletConnection'>
DEBUG Connecting to cluster, contact points: ['uscstardev01', 'uscstardev02', 'uscstardev03']; protocol version: 4
DEBUG Host 172.16.9.29:9042 is now marked up
DEBUG Host 172.16.9.30:9042 is now marked up
DEBUG Host 172.16.9.31:9042 is now marked up
DEBUG [control connection] Opening new connection to 172.16.9.31:9042
DEBUG Sending initial options message for new connection (140349806704400) to 172.16.9.31:9042
DEBUG Received options response on new connection (140349806704400) from 172.16.9.31:9042
DEBUG Sending StartupMessage on <EventletConnection(140349806704400) 172.16.9.31:9042>
DEBUG Sent StartupMessage on <EventletConnection(140349806704400) 172.16.9.31:9042>
DEBUG Got ReadyMessage on new connection (140349806704400) from 172.16.9.31:9042
DEBUG [control connection] Established new connection <EventletConnection(140349806704400) 172.16.9.31:9042>, registering watchers and refreshing schema and topology
DEBUG [control connection] Refreshing node list and token map using preloaded results
INFO Using datacenter 'devus01' for DCAwareRoundRobinPolicy (via host '172.16.9.31:9042'); if incorrect, please specify a local_dc to the constructor, or limit contact points to local cluster nodes
DEBUG [control connection] Finished fetching ring info
DEBUG [control connection] Rebuilding token map due to topology changes
DEBUG Control connection created
DEBUG Initializing connection for host 172.16.9.29:9042
DEBUG Sending initial options message for new connection (140349806806968) to 172.16.9.29:9042
DEBUG Initializing connection for host 172.16.9.30:9042
DEBUG Sending initial options message for new connection (140349805903544) to 172.16.9.30:9042
DEBUG Received options response on new connection (140349806806968) from 172.16.9.29:9042
DEBUG Sending StartupMessage on <EventletConnection(140349806806968) 172.16.9.29:9042>
DEBUG Sent StartupMessage on <EventletConnection(140349806806968) 172.16.9.29:9042>
DEBUG Received options response on new connection (140349805903544) from 172.16.9.30:9042
DEBUG Sending StartupMessage on <EventletConnection(140349805903544) 172.16.9.30:9042>
DEBUG Sent StartupMessage on <EventletConnection(140349805903544) 172.16.9.30:9042>
DEBUG Got ReadyMessage on new connection (140349806806968) from 172.16.9.29:9042
DEBUG Finished initializing connection for host 172.16.9.29:9042
DEBUG Added pool for host 172.16.9.29:9042 to session
DEBUG Initializing connection for host 172.16.9.31:9042
DEBUG Got ReadyMessage on new connection (140349805903544) from 172.16.9.30:9042
DEBUG Finished initializing connection for host 172.16.9.30:9042
DEBUG Added pool for host 172.16.9.30:9042 to session
最后一条消息是在进程挂起之前出现的最后一条消息。
这是我的环境：
adyne_services_common 0.1 py37_0
alphasuite 1.79a1 py37_0
amqp 2.3.2 py_1
appdirs 1.4.3 py37h28b3542_0
arrow 0.12.1 py37_1
asn1crypto 0.24.0 py37_0
attrs 18.2.0 py37h28b3542_0
backcall 0.1.0 py37_0
backports 1 py37_1
backports.os 0.1.1 py37_0
bcrypt 3.1.5 py37h7b6447c_0
beautifulsoup4 4.6.3 py37_0
billiard 3.6.0.0 py37h516909a_0
blas 1 mkl
blpapi 3.12.2 py37_blpapicpp3.12.2.1_1
ca-certificates 2018.03.07 0
cached-property 1.5.1 py37_0
cachetools 3.0.0 py_0
cassandra-driver 3.18.0 py37_0
celery 4.3.0 py_1
certifi 2018.11.29 py37_0
cffi 1.11.5 py37he75722e_1
chardet 3.0.4 py37_1
conda 4.5.12 py37_0
conda-env 2.6.0 1
cryptography 2.4.2 py37h1ba5d50_0
cycler 0.10.0 py37_0
cython 0.28.5 py37hf484d3e_0
dbus 1.13.2 h714fa37_1
decorator 4.3.0 py37_0
defusedxml 0.5.0 py37_1
distro 1.4.0 py_0
elasticsearch 5.4.0 py37_0
et_xmlfile 1.0.1 py37_0
eventlet 0.23.0 py37_1000
expat 2.2.6 he6710b0_0
fontconfig 2.13.0 h9420a91_0
freetype 2.9.1 h8a8886c_1
glib 2.56.2 hd408876_0
greenlet 0.4.15 py37h7b6447c_0
gst-plugins-base 1.14.0 hbbd80ab_1
gstreamer 1.14.0 hb453b48_1
icu 58.2 h211956c_0
idna 2.8 py37_0
importlib_metadata 0.6 py37_0
intel-openmp 2019.1 144
ipython 7.2.0 py37h39e3cac_0
ipython_genutils 0.2.0 py37_0
isodate 0.6.0 py37_0
jdcal 1.4 py37_0
jedi 0.13.2 py37_0
jinja2 2.1 py37_0
jpeg 9b habf39ab_1
jsonschema 2.6.0 py37_0
kiwisolver 1.0.1 py37hf484d3e_0
kombu 4.6.1 py_0
krb5 1.16.1 h173b8e3_7
libedit 3.1.20170329 h6b74fdf_2
libffi 3.2.1 h4deb6c0_3
libgcc-ng 8.2.0 hdf63c60_1
libgfortran-ng 7.3.0 hdf63c60_0
libpng 1.6.35 hbc83047_0
libsodium 1.0.16 h1bed415_0
libstdcxx-ng 8.2.0 hdf63c60_1
libuuid 1.0.3 h1bed415_2
libxcb 1.13 h1bed415_1
libxml2 2.9.8 h26e45fe_1
libxslt 1.1.32 h1312cb7_0
lxml 4.2.5 py37hefd8a0e_0
lz4 2.1.6 py37h7b6447c_0
lz4-c 1.8.1.2 h14c3975_0
markupsafe 1.1.0 py37h7b6447c_0
matplotlib 3.0.2 py37h5429711_0
mkl 2019.1 144
mkl_fft 1.0.6 py37hd81dba3_0
mkl_random 1.0.2 py37hd81dba3_0
mock 2.0.0 py37_0
mysqlclient 1.3.14 ubuntu1404
nameko 2.11.0 py37_3
ncurses 6.1 he6710b0_1
numpy 1.15.4 py37h7e9f1db_0
numpy-base 1.15.4 py37hde5b4d6_0
openjdk 8.0.121 1
openpyxl 2.5.12 py37_0
openssl 1.1.1 h7b6447c_0
pandas 0.23.4 py37h04863e7_0
paramiko 2.4.2 py37_0
parso 0.3.1 py37_0
path.py 11.5.0 py37_0
patsy 0.5.1 py37_0
pbr 5.1.1 py37_0
pcre 8.42 h439df22_0
pexpect 4.6.0 py37_0
pickleshare 0.7.5 py37_0
pika 0.12.0 py_1
pip 18.1 py37_0
pipeline 0.68a1 py37_1
prompt_toolkit 2.0.7 py37_0
ptyprocess 0.6.0 py37_0
pyasn1 0.4.5 py_0
pycosat 0.6.3 py37h14c3975_0
pycparser 2.19 py37_0
pygments 2.3.1 py37_0
pykerberos 1.2.1 py37h14c3975_0
pynacl 1.2.1 py37h14c3975_0
pyodbc 4.0.25 py37he6710b0_0
pyopenssl 18.0.0 py37_0
pyparsing 2.3.0 py37_0
pyqt 5.9.2 py37h05f1152_2
pysocks 1.6.8 py37_0
python 3.7.1 h0371630_7
python-dateutil 2.7.5 py37_0
pytz 2018.7 py37_0
pyvolar 3.10.8 py37_1
pyyaml 3.13 py37h14c3975_0
qt 5.9.7 h5867ecd_1
readline 7 h7b6447c_5
redis-py 3.2.0 py_0
requests 2.21.0 py37_0
requests-kerberos 0.12.0 py37_0
requests-toolbelt 0.8.0 py37_0
ruamel_yaml 0.15.46 py37h14c3975_0
scipy 1.1.0 py37h7c811a0_2
seaborn 0.9.0 py37_0
setuptools 40.6.3 py37_0
simplejson 3.16.0 py37h14c3975_0
sip 4.19.8 py37hf484d3e_0
six 1.12.0 py37_0
sqlalchemy 1.2.15 py37h7b6447c_0
sqlite 3.26.0 h7b6447c_0
statsmodels 0.9.0 py37h035aef0_0
tabula-py 1.1.1 py37_1000
tk 8.6.8 hbc83047_0
tornado 5.1.1 py37h7b6447c_0
traitlets 4.3.2 py37_0
ujson 1.35 py37h14c3975_0
unixodbc 2.3.7 h14c3975_0
urllib3 1.24.1 py37_0
vine 1.3.0 py_0
wcwidth 0.1.7 py37_0
werkzeug 0.14.1 py37_0
wheel 0.32.3 py37_0
wrapt 1.10.11 py37h14c3975_2
xlrd 1.2.0 py37_0
xlwt 1.3.0 py37_0
xz 5.2.4 h14c3975_4
yaml 0.1.7 h96e3832_1
zeep 3.2.0 py_1000
zlib 1.2.11 h7b6447c_3
答案 0 :(得分：2)
这是我们在最新的cassandra驱动程序版本（3.19.0）中修复的问题。但是，您将需要安装“ futurist”软件包才能使eventlet与Python 3.7一起使用。有关更多详细信息，请参见https://github.com/eventlet/eventlet/issues/508