[python][examples] Add Python streaming word count examples

flink-python/docs/examples/datastream/word_count.rst

@@ -20,4 +20,12 @@
 Word Count
 ==========
 
+Word Count
+==========
+
 .. literalinclude:: ../../../pyflink/examples/datastream/word_count.py
+
+Streaming Word Count
+====================
+
+.. literalinclude:: ../../../pyflink/examples/datastream/streaming_word_count.py

flink-python/docs/examples/table/word_count.rst

@@ -20,4 +20,12 @@
 Word Count
 ==========
 
+Word Count
+==========
+
 .. literalinclude:: ../../../pyflink/examples/table/word_count.py
+
+Streaming Word Count
+====================
+
+.. literalinclude:: ../../../pyflink/examples/table/streaming_word_count.py

flink-python/pyflink/examples/datastream/streaming_word_count.py

@@ -0,0 +1,100 @@
+################################################################################
+# 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:https://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.
+################################################################################
+import argparse
+import logging
+import sys
+
+from pyflink.common import Encoder, Types
+from pyflink.datastream import StreamExecutionEnvironment
+from pyflink.datastream.connectors.file_system import (FileSink, OutputFileConfig, RollingPolicy)
+from pyflink.table import StreamTableEnvironment, TableDescriptor, Schema, DataTypes
+
+words = ["flink", "window", "timer", "event_time", "processing_time", "state",
+ "connector", "pyflink", "checkpoint", "watermark", "sideoutput", "sql",
+ "datastream", "broadcast", "asyncio", "catalog", "batch", "streaming"]
+
+max_word_id = len(words) - 1
+
+
+def word_count(output_path):
+ env = StreamExecutionEnvironment.get_execution_environment()
+ t_env = StreamTableEnvironment.create(stream_execution_environment=env)
+
+ # define the source
+ # randomly select 5 words per second from a predefined list
+ t_env.create_temporary_table(
+ 'source',
+ TableDescriptor.for_connector('datagen')
+ .schema(Schema.new_builder()
+ .column('word_id', DataTypes.INT())
+ .build())
+ .option('fields.word_id.kind', 'random')
+ .option('fields.word_id.min', '0')
+ .option('fields.word_id.max', str(max_word_id))
+ .option('rows-per-second', '5')
+ .build())
+
+ table = t_env.from_path('source')
+ ds = t_env.to_data_stream(table)
+
+ def id_to_word(r):
+ # word_id is the first column of the input row
+ return words[r[0]]
+
+ # compute word count
+ ds = ds.map(id_to_word) \
+ .map(lambda i: (i, 1), output_type=Types.TUPLE([Types.STRING(), Types.INT()])) \
+ .key_by(lambda i: i[0]) \
+ .reduce(lambda i, j: (i[0], i[1] + j[1]))
+
+ # define the sink
+ if output_path is not None:
+ ds.sink_to(
+ sink=FileSink.for_row_format(
+ base_path=output_path,
+ encoder=Encoder.simple_string_encoder())
+ .with_output_file_config(
+ OutputFileConfig.builder()
+ .with_part_prefix("prefix")
+ .with_part_suffix(".ext")
+ .build())
+ .with_rolling_policy(RollingPolicy.default_rolling_policy())
+ .build()
+ )
+ else:
+ print("Printing result to stdout. Use --output to specify output path.")
+ ds.print()
+
+ # submit for execution
+ env.execute()
+
+
+if __name__ == '__main__':
+ logging.basicConfig(stream=sys.stdout, level=logging.INFO, format="%(message)s")
+
+ parser = argparse.ArgumentParser()
+ parser.add_argument(
+ '--output',
+ dest='output',
+ required=False,
+ help='Output file to write results to.')
+
+ argv = sys.argv[1:]
+ known_args, _ = parser.parse_known_args(argv)
+
+ word_count(known_args.output)

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

@@ -0,0 +1,104 @@
+################################################################################
+# 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:https://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.
+################################################################################
+import argparse
+import logging
+import sys
+
+from pyflink.table import TableEnvironment, EnvironmentSettings, TableDescriptor, Schema,\
+ DataTypes, FormatDescriptor
+from pyflink.table.expressions import col, lit
+from pyflink.table.udf import udf
+
+words = ["flink", "window", "timer", "event_time", "processing_time", "state",
+ "connector", "pyflink", "checkpoint", "watermark", "sideoutput", "sql",
+ "datastream", "broadcast", "asyncio", "catalog", "batch", "streaming"]
+
+max_word_id = len(words) - 1
+
+
+def streaming_word_count(output_path):
+ t_env = TableEnvironment.create(EnvironmentSettings.in_streaming_mode())
+
+ # define the source
+ # randomly select 5 words per second from a predefined list
+ t_env.create_temporary_table(
+ 'source',
+ TableDescriptor.for_connector('datagen')
+ .schema(Schema.new_builder()
+ .column('word_id', DataTypes.INT())
+ .build())
+ .option('fields.word_id.kind', 'random')
+ .option('fields.word_id.min', '0')
+ .option('fields.word_id.max', str(max_word_id))
+ .option('rows-per-second', '5')
+ .build())
+ tab = t_env.from_path('source')
+
+ # define the sink
+ if output_path is not None:
+ t_env.create_temporary_table(
+ 'sink',
+ TableDescriptor.for_connector('filesystem')
+ .schema(Schema.new_builder()
+ .column('word', DataTypes.STRING())
+ .column('count', DataTypes.BIGINT())
+ .build())
+ .option('path', output_path)
+ .format(FormatDescriptor.for_format('canal-json')
+ .build())
+ .build())
+ else:
+ print("Printing result to stdout. Use --output to specify output path.")
+ t_env.create_temporary_table(
+ 'sink',
+ TableDescriptor.for_connector('print')
+ .schema(Schema.new_builder()
+ .column('word', DataTypes.STRING())
+ .column('count', DataTypes.BIGINT())
+ .build())
+ .build())
+
+ @udf(result_type='string')
+ def id_to_word(word_id):
+ return words[word_id]
+
+ # compute word count
+ tab.select(id_to_word(col('word_id'))).alias('word') \
+ .group_by(col('word')) \
+ .select(col('word'), lit(1).count) \
+ .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")
+
+ parser = argparse.ArgumentParser()
+ parser.add_argument(
+ '--output',
+ dest='output',
+ required=False,
+ help='Output file to write results to.')
+
+ argv = sys.argv[1:]
+ known_args, _ = parser.parse_known_args(argv)
+
+ streaming_word_count(known_args.output)