如何使用Python驱动程序获取Cassandra集群的名称？

Question

When I connect to Cassandra using cqlsh , it tells me the name of the Cassandra cluster I'm connected to.

$ cqlsh
Connected to Test Cluster at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 3.11.2 | CQL spec 3.4.4 | Native protocol v4]
Use HELP for help.
cqlsh>

(In this example the cluster name is Test Cluster , and it appears in blue on my screen.)

How do I get the cluster name from within my Python code, using the Python Cassandra driver? I expected to be able to get this information from the Session object, but I cannot see anything in the documentation .

(My use case is part of a belt-and-braces approach to prevent tests from being run against production Cassandras. The idea is that if the server name indicates that the tests have connected to a production Cassandra somehow, they can abort ASAP.)

Answer 1

cassandra.metadata-架构和环形拓扑

Answer 2

You can also find the cluster name (and other information) by querying the system.local table:

from cassandra.cluster import Cluster
from cassandra.auth import PlainTextAuthProvider
import sys

hostname=sys.argv[1]
username=sys.argv[2]
password=sys.argv[3]

nodes = []
nodes.append(hostname)
auth_provider = PlainTextAuthProvider(username=username, password=password)
ssl_opts = {'ca_certs':'/home/aaron/.cassandra/mycert.pem'}
cluster = Cluster(nodes,auth_provider=auth_provider,ssl_options=ssl_opts)
session = cluster.connect()

strCQL = "SELECT cluster_name FROM system.local"
pStatement = session.prepare(strCQL)
rows = session.execute(pStatement)

for row in rows:
    print row[0]

session.shutdown()

Save that as getCluster.py and run it to see:

$ python getCluster.py 192.168.0.101 aaron flynnLives
AaronsHomeCluster