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#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
from __future__ import print_function
import sys
from pyspark import SparkContext
"""
Create data in Cassandra fist
(following: https://wiki.apache.org/cassandra/GettingStarted)
cqlsh> CREATE KEYSPACE test
... WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };
cqlsh> use test;
cqlsh:test> CREATE TABLE users (
... user_id int PRIMARY KEY,
... fname text,
... lname text
... );
cqlsh:test> INSERT INTO users (user_id, fname, lname)
... VALUES (1745, 'john', 'smith');
cqlsh:test> INSERT INTO users (user_id, fname, lname)
... VALUES (1744, 'john', 'doe');
cqlsh:test> INSERT INTO users (user_id, fname, lname)
... VALUES (1746, 'john', 'smith');
cqlsh:test> SELECT * FROM users;
user_id | fname | lname
---------+-------+-------
1745 | john | smith
1744 | john | doe
1746 | john | smith
"""
if __name__ == "__main__":
if len(sys.argv) != 4:
print("""
Usage: cassandra_inputformat <host> <keyspace> <cf>
Run with example jar:
./bin/spark-submit --driver-class-path /path/to/example/jar \
/path/to/examples/cassandra_inputformat.py <host> <keyspace> <cf>
Assumes you have some data in Cassandra already, running on <host>, in <keyspace> and <cf>
""", file=sys.stderr)
exit(-1)
host = sys.argv[1]
keyspace = sys.argv[2]
cf = sys.argv[3]
sc = SparkContext(appName="CassandraInputFormat")
conf = {"cassandra.input.thrift.address": host,
"cassandra.input.thrift.port": "9160",
"cassandra.input.keyspace": keyspace,
"cassandra.input.columnfamily": cf,
"cassandra.input.partitioner.class": "Murmur3Partitioner",
"cassandra.input.page.row.size": "3"}
cass_rdd = sc.newAPIHadoopRDD(
"org.apache.cassandra.hadoop.cql3.CqlPagingInputFormat",
"java.util.Map",
"java.util.Map",
keyConverter="org.apache.spark.examples.pythonconverters.CassandraCQLKeyConverter",
valueConverter="org.apache.spark.examples.pythonconverters.CassandraCQLValueConverter",
conf=conf)
output = cass_rdd.collect()
for (k, v) in output:
print((k, v))
sc.stop()
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