flink-python/docs/getting_started/quickstart.rst

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Quickstart
==========

This quickstart guide will help you get up and running with PyFlink in just a few minutes. You'll learn how to:

1. Set up a PyFlink environment
2. Create a simple streaming job
3. Run your first PyFlink application

Prerequisites
-------------

Before you begin, make sure you have:

- Python 3.9, 3.10, 3.11, or 3.12 installed
- PyFlink installed (see :doc:`installation`)

Your First PyFlink Application
------------------------------

Let's create a simple streaming application that reads from a socket and counts words in real-time.

Create a file named ``word_count.py`` with the following content:

.. code-block:: python

   from pyflink.datastream import StreamExecutionEnvironment
   from pyflink.table import StreamTableEnvironment, EnvironmentSettings

   def word_count_streaming():
       # Create a streaming execution environment
       env = StreamExecutionEnvironment.get_execution_environment()

       # Create a table environment
       settings = EnvironmentSettings.new_instance().in_streaming_mode().build()
       table_env = StreamTableEnvironment.create(env, settings)

       # Create a source table from socket
       source_ddl = """
           CREATE TABLE source (
               word STRING
           ) WITH (
               'connector' = 'socket',
               'hostname' = 'localhost',
               'port' = '9999',
               'format' = 'csv'
           )
       """

       # Create a sink table to print results
       sink_ddl = """
           CREATE TABLE sink (
               word STRING,
               count BIGINT
           ) WITH (
               'connector' = 'print'
           )
       """

       # Execute DDL statements
       table_env.execute_sql(source_ddl)
       table_env.execute_sql(sink_ddl)

       # Create a query
       table_env.sql_query("""
           SELECT word, COUNT(*) as count
           FROM source
           GROUP BY word
       """).execute_insert('sink')

   if __name__ == '__main__':
       word_count_streaming()

Running the Application
-----------------------

1. **Start a socket server** (in a separate terminal):

   .. code-block:: bash

      nc -lk 9999

2. **Run your PyFlink application**:

   .. code-block:: bash

      python word_count.py

3. **Send some text** to the socket (in the nc terminal):

   .. code-block:: text

      hello world
      hello flink
      world of streaming

You should see the word count results printed in your PyFlink application output.

What's Next?
------------

Now that you've run your first PyFlink application, you can explore:

- :doc:`../user_guide/datastream_tutorial` - Learn about the DataStream API
- :doc:`../user_guide/table_api_tutorial` - Learn about the Table API & SQL
- :doc:`../examples/index` - Browse complete examples
- :doc:`../cookbook/index` - Find practical recipes for common tasks

For more complex examples and tutorials, check out the :doc:`../examples/index` section.