flink-python/pyflink/examples/table/process_json_data_with_udf.py

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import json
import logging
import sys

from pyflink.table import (EnvironmentSettings, TableEnvironment, DataTypes, TableDescriptor,
                           Schema)
from pyflink.table.udf import udf


def process_json_data_with_udf():
    t_env = TableEnvironment.create(EnvironmentSettings.in_streaming_mode())

    # define the source
    table = t_env.from_elements(
        elements=[
            (1, '{"name": "Flink", "tel": 123, "addr": {"country": "Germany", "city": "Berlin"}}'),
            (2, '{"name": "hello", "tel": 135, "addr": {"country": "China", "city": "Shanghai"}}'),
            (3, '{"name": "world", "tel": 124, "addr": {"country": "USA", "city": "NewYork"}}'),
            (4, '{"name": "PyFlink", "tel": 32, "addr": {"country": "China", "city": "Hangzhou"}}')
        ],
        schema=['id', 'data'])

    # define the sink
    t_env.create_temporary_table(
        'sink',
        TableDescriptor.for_connector('print')
                       .schema(Schema.new_builder()
                               .column('id', DataTypes.BIGINT())
                               .column('data', DataTypes.STRING())
                               .build())
                       .build())

    # update json columns
    @udf(result_type=DataTypes.STRING())
    def update_tel(data):
        json_data = json.loads(data)
        json_data['tel'] += 1
        return json.dumps(json_data)

    table = table.select(table.id, update_tel(table.data))

    # execute
    table.execute_insert('sink') \
         .wait()
    # remove .wait if submitting to a remote cluster, refer to
    # https://nightlies.apache.org/flink/flink-docs-stable/docs/dev/python/faq/#wait-for-jobs-to-finish-when-executing-jobs-in-mini-cluster
    # for more details


if __name__ == '__main__':
    logging.basicConfig(stream=sys.stdout, level=logging.INFO, format="%(message)s")

    process_json_data_with_udf()