Python Sample Code
Function
Submit Flink Kafka read and write jobs to Yarn through Python APIs.
Sample Code
The main logic code in pyflink-kafka.py is provided. Before submitting the code, ensure that file_path is the path where the SQL statement to be executed. You are advised to use a full path.
import os import logging import sys from pyflink.common import JsonRowDeserializationSchema, JsonRowSerializationSchema from pyflink.common.typeinfo import Types from pyflink.datastream.connectors import FlinkKafkaProducer, FlinkKafkaConsumer from pyflink.datastream import StreamExecutionEnvironment from pyflink.table import TableEnvironment, EnvironmentSettings def read_sql(file_path): if not os.path.isfile(file_path): raise TypeError(file_path + " does not exist") all_the_text = open(file_path).read() return all_the_text def exec_sql(): # Change the SQL path before job submission. # file_path = "/opt/client/Flink/flink/insertData2kafka.sql" # file_path = os.getcwd() + "/../../../../yarnship/insertData2kafka.sql" # file_path = "/opt/client/Flink/flink/conf/ssl/insertData2kafka.sql" file_path = "insertData2kafka.sql" sql = read_sql(file_path) t_env = TableEnvironment.create(EnvironmentSettings.in_streaming_mode()) statement_set = t_env.create_statement_set() sqlArr = sql.split(";") for sqlStr in sqlArr: sqlStr = sqlStr.strip() if sqlStr.lower().startswith("create"): print("---------create---------------") print(sqlStr) t_env.execute_sql(sqlStr) if sqlStr.lower().startswith("insert"): print("---------insert---------------") print(sqlStr) statement_set.add_insert_sql(sqlStr) statement_set.execute() def read_write_kafka(): # find kafka connector jars env = StreamExecutionEnvironment.get_execution_environment() env.set_parallelism(1) specific_jars = "file:///opt/client/Flink/flink/lib/flink-connector-kafka-xxx.jar" # specific_jars = "file://" + os.getcwd() + "/../../../../yarnship/flink-connector-kafka-xxx.jar" # specific_jars = "file:///opt/client/Flink/flink/conf/ssl/flink-connector-kafka-xxx.jar" # the sql connector for kafka is used here as it's a fat jar and could avoid dependency issues env.add_jars(specific_jars) kafka_properties = {'bootstrap.servers': '192.168.20.162:21005', 'group.id': 'test_group'} deserialization_schema = JsonRowDeserializationSchema.builder() \ .type_info(type_info=Types.ROW([Types.INT(), Types.STRING()])).build() kafka_consumer = FlinkKafkaConsumer( topics='test_source_topic', deserialization_schema=deserialization_schema, properties=kafka_properties) print("---------read ---------------") ds = env.add_source(kafka_consumer) serialization_schema = JsonRowSerializationSchema.builder().with_type_info( type_info=Types.ROW([Types.INT(), Types.STRING()])).build() kafka_producer = FlinkKafkaProducer( topic='test_sink_topic', serialization_schema=serialization_schema, producer_config=kafka_properties) print("--------write------------------") ds.add_sink(kafka_producer) env.execute("pyflink kafka test") if __name__ == '__main__': logging.basicConfig(stream=sys.stdout, level=logging.INFO, format="%(message)s") print("------------------insert data to kafka----------------") exec_sql() print("------------------read_write_kafka----------------") read_write_kafka()
Parameter |
Description |
Example |
---|---|---|
bootstrap.servers |
Service IP address and port number of the Broker instance of Kafka |
192.168.12.25:21005 |
specific_jars |
Package path: Client installation directory/Flink/flink/lib/flink-connector-kafka-*.jar. You are advised to use a full path.
NOTE:
If a job needs to be submitted as yarn-application, replace the following path. Replace the JAR package version with the actual one. specific_jars="file://"+os.getcwd()+"/../../../../yarnship/flink-connector-kafka-1.15.0-h0.cbu.mrs.330.r13.jar" |
specific_jars = file:///Client installation directory/Flink/flink/lib/flink-connector-kafka-1.15.0-h0.cbu.mrs.330.r13.jar |
file_path |
Path of the insertData2kafka.sql file. You are advised to use a full path. Obtain the package from the secondary development sample code and upload it to the specified directory on the client.
NOTE:
If a job needs to be submitted as yarn-application, replace the following path: file_path = os.getcwd() + "/../../../../yarnship/insertData2kafka.sql" |
file_path = /Client installation directory/Flink/flink/insertData2kafka.sql |
create table kafka_sink_table ( age int, name varchar(10) ) with ( 'connector' = 'kafka', 'topic' = 'test_source_topic', --Name of the topic written to Kafka. Ensure that the topic name is the same as that in the Python file. 'properties.bootstrap.servers' = 'IP address of the Kafka broker instance:Kafka port number', 'properties.group.id' = 'test_group', 'format' = 'json' ); create TABLE datagen_source_table ( age int, name varchar(10) ) WITH ( 'connector' = 'datagen', 'rows-per-second' = '1' ); INSERT INTO kafka_sink_table SELECT * FROM datagen_source_table;
Feedback
Was this page helpful?
Provide feedbackThank you very much for your feedback. We will continue working to improve the documentation.See the reply and handling status in My Cloud VOC.
For any further questions, feel free to contact us through the chatbot.
Chatbot