dump big cassandra table

cassandra_dump.py

# -*- coding:utf-8 -*- #

import sys
reload(sys)
sys.setdefaultencoding("utf-8")

import codecs

try:
    import cassandra
    import cassandra.concurrent
except ImportError:
    sys.exit('Python Cassandra driver not installed. You might try \"pip install cassandra-driver\".')

from cassandra.auth import PlainTextAuthProvider #For protocol_version 2
from cassandra.cluster import Cluster

class CassandraHelper:

  def __init__(self, host="127.0.0.1", keyspace="", fetch_size=100):
    self.cluster = Cluster([host])
    self.session = self.cluster.connect(keyspace)
    self.session.default_fetch_size = fetch_size
    self.session.row_factory = cassandra.query.ordered_dict_factory

  def cleanup_cluster(self):
    self.session.cluster.shutdown()
    self.session.shutdown()

  def dump(self, tablename):
    query = "SELECT * FROM %s" % tablename
    rows = self.session.execute(query)
    for row in rows:
      yield row

def main():
  if len(sys.argv) < 2:
    print "Usage: %s <tablename> (keyspace) (host)" % sys.argv[0]
    return

  tablename = sys.argv[1]

  if len(sys.argv) >= 3:
    keyspace = sys.argv[2]
  else:
    keyspace = "test"

  if len(sys.argv) >= 4:
    host = sys.argv[3]
  else:
    host = "192.168.1.100"

  cass = CassandraHelper(host=host, keyspace=keyspace)

  for row in cass.dump(tablename):
    try:
      uid = row['uid']
      ts = long(row['ts'])
      data = row['data']

      print "%s,%s,%s" % (uid, ts, data)

    except:
      pass

  cass.cleanup_cluster()

main()