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A Python wrapper for the KSQL REST API

Project description

A python wrapper for the KSQL REST API. Easily interact with the KSQL REST API using this library.

Supported KSQL version: 5.x

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Installation

pip install ksql

Or

git clone https://github.com/bryanyang0528/ksql-python
cd ksql-python
python setup.py install

Getting Started

Setup for KSQL

This is the GITHUB page of KSQL. https://github.com/confluentinc/ksql

If you have installed open source Confluent CLI (e.g. by installing Confluent Open Source or Enterprise Platform), you can start KSQL and its dependencies with one single command:

confluent start ksql-server

Setup for ksql-python API

  • Setup for the KSQL API:
from ksql import KSQLAPI
client = KSQLAPI('http://ksql-server:8088')
  • Setup for KSQl API with logging enabled:
import logging
from ksql import KSQLAPI
logging.basicConfig(level=logging.DEBUG)
client = KSQLAPI('http://ksql-server:8088')

Options

Option Type Required Description
url string yes Your ksql-server url. Example: http://ksql-server:8080
timeout integer no Timout for Requests. Default: 5

Main Methods

ksql

This method can be used for some KSQL features which are not supported via other specific methods like query, create_stream or create_stream_as. The following example shows how to execute the show tables statement:

client.ksql('show tables')
  • Example Response [{'tables': {'statementText': 'show tables;', 'tables': []}}]

query

It will execute sql query and keep listening streaming data.

client.query('select * from table1')

This command returns a generator. It can be printed e.g. by reading its values via next(query) or a for loop. Here is a complete example:

from ksql import KSQLAPI
client = KSQLAPI('http://localhost:8088')
query = client.query('select * from table1')
for item in query: print(item)
  • Example Response

    {"row":{"columns":[1512787743388,"key1",1,2,3]},"errorMessage":null}
    {"row":{"columns":[1512787753200,"key1",1,2,3]},"errorMessage":null}
    {"row":{"columns":[1512787753488,"key1",1,2,3]},"errorMessage":null}
    {"row":{"columns":[1512787753888,"key1",1,2,3]},"errorMessage":null}
    

Simplified API

create_stream/ create_table

client.create_stream(table_name=table_name,
                     columns_type=columns_type,
                     topic=topic,
                     value_format=value_format)

Options

Option Type Required Description
table_name string yes name of stream/table
columns_type list yes ex:['viewtime bigint','userid varchar','pageid varchar']
topic string yes Kafka topic
value_format string no JSON (Default) or DELIMITED or AVRO
key string for Table Key (used for JOINs)
  • Responses
If create table/stream succeed:
 return True
If failed:raise a CreateError(respose_from_ksql_server)

create_stream_as

a simplified api for creating stream as select

client.create_stream_as(table_name=table_name,
                        select_columns=select_columns,
                        src_table=src_table,
                        kafka_topic=kafka_topic,
                        value_format=value_format,
                        conditions=conditions,
                        partition_by=partition_by,
                        **kwargs)
CREATE STREAM <table_name>
[WITH ( kafka_topic=<kafka_topic>, value_format=<value_format>, property_name=expression ... )]
AS SELECT  <select_columns>
FROM <src_table>
[WHERE <conditions>]
PARTITION BY <partition_by>];

Options

Option Type Required Description
table_name string yes name of stream/table
select_columns list yes you can select [*] or ['columnA', 'columnB']
src_table string yes name of source table
kafka_topic string no The name of the Kafka topic of this new stream(table).
value_format string no DELIMITED, JSON``(Default) or ``AVRO
conditions string no The conditions in the where clause.
partition_by string no Data will be distributed across partitions by this column.
kwargs pair no please provide key=value pairs. Please see more options.

KSQL JOINs

KSQL JOINs between Streams and Tables are not supported yet via explicit methods, but you can use the ksql method for this like the following:

client.ksql("CREATE STREAM join_per_user WITH (VALUE_FORMAT='AVRO', KAFKA_TOPIC='join_per_user') AS SELECT Time, Amount FROM source c INNER JOIN users u on c.user = u.userid WHERE u.USERID = 1")

FileUpload

upload

Run commands from a .ksql file. Can only support ksql commands and not streaming queries.

from ksql import FileUpload
pointer = FileUpload('http://ksql-server:8080')
pointer.upload('rules.ksql')

Options

Option Type Required Description
ksqlfile string yes name of file containing the rules
  • Responses
If ksql-commands succesfully executed:
 return (List of server response for all commands)
If failed:raise the appropriate error

More Options

There are more properties (partitions, replicas, etc…) in the official document.

KSQL Syntax Reference

  • Responses
If create table/stream succeed:
 return True
If failed:raise a CreatError(respose_from_ksql_server)

Project details


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