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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 KSQLDB version: 0.10.1+ Supported Python version: 3.5+

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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')
  • 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 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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