ksql-python

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

Supported KSQLDB version: 0.10.1+ Supported Python version: 3.5+

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')

• Setup for KSQL API with Basic Authentication

from ksql import KSQLAPI
client = KSQLAPI('http://ksql-server:8088', api_key="your_key", secret="your_secret")

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
api_key	string	no	API Key to use on the requests
secret	string	no	Secret to use on the requests

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}
  

Query with HTTP/2

Execute queries with the new /query-stream endpoint. Documented here

To execute a sql query use the same syntax as the regular query, with the additional use_http2=True parameter.

client.query('select * from table1', use_http2=True)

A generator is returned with the following example response

{"queryId":"44d8413c-0018-423d-b58f-3f2064b9a312","columnNames":["ORDER_ID","TOTAL_AMOUNT","CUSTOMER_NAME"],"columnTypes":["INTEGER","DOUBLE","STRING"]}
[3,43.0,"Palo Alto"]
[3,43.0,"Palo Alto"]
[3,43.0,"Palo Alto"]

To terminate the query above use the close_query call. Provide the queryId returned from the query call.

client.close_query("44d8413c-0018-423d-b58f-3f2064b9a312")

Insert rows into a Stream with HTTP/2

Uses the new /inserts-stream endpoint. See documentation

rows = [
        {"ORDER_ID": 1, "TOTAL_AMOUNT": 23.5, "CUSTOMER_NAME": "abc"},
        {"ORDER_ID": 2, "TOTAL_AMOUNT": 3.7, "CUSTOMER_NAME": "xyz"}
    ]

results = self.api_client.inserts_stream("my_stream_name", rows)

An array of object will be returned on success, with the status of each row inserted.

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.upload 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)