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Python library for building stream processing applications with Apache Kafka

Project description

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Quix Streams

Quix Streams is a cloud native library for processing data in Kafka using pure Python. It’s designed to give you the power of a distributed system in a lightweight library by combining the low-level scalability and resiliency features of Kafka with an easy to use Python interface (to ease newcomers to stream processing).

Quix Streams has the following benefits:

  • Pure Python (no JVM, no wrappers, no cross-language debugging).
  • No orchestrator, no server-side engine.
  • Streaming DataFrame API (similar to pandas DataFrame) for tabular data transformations.
  • Easily integrates with the entire Python ecosystem (pandas, scikit-learn, TensorFlow, PyTorch etc).
  • Support for many serialization formats, including JSON (and Quix-specific).
  • Support for stateful operations using RocksDB.
  • Support for aggregations over tumbling and hopping time windows.
  • "At-least-once" and "exactly-once" Kafka processing guarantees.
  • Designed to run and scale resiliently via container orchestration (like Kubernetes).
  • Easily runs locally and in Jupyter Notebook for convenient development and debugging.
  • Seamless integration with the fully managed Quix Cloud platform.

Use Quix Streams to build event-driven, machine learning/AI or physics-based applications that depend on real-time data from Kafka.

Getting started 🏄

Install Quix Streams

python -m pip install quixstreams


Python 3.8+, Apache Kafka 0.10+

See requirements.txt for the full list of requirements


Quix Streams Docs

Example Application

Here's an example of how to process data from a Kafka Topic with Quix Streams:

from quixstreams import Application, State

# Define an application
app = Application(
    broker_address="localhost:9092",  # Kafka broker address
    consumer_group="consumer-group-name",  # Kafka consumer group

# Define the input and output topics. By default, "json" serialization will be used
input_topic = app.topic("my_input_topic")
output_topic = app.topic("my_output_topic")

def count(data: dict, state: State):
    # Get a value from state for the current Kafka message key
    total = state.get('total', default=0)
    total += 1
    # Set a value back to the state
    state.set('total', total)
    # Update your message data with a value from the state
    data['total'] = total

# Create a StreamingDataFrame instance
# StreamingDataFrame is a primary interface to define the message processing pipeline
sdf = app.dataframe(topic=input_topic)

# Print the incoming messages
sdf = sdf.update(lambda value: print('Received a message:', value))

# Select fields from incoming messages
sdf = sdf[["field_1", "field_2", "field_3"]]

# Filter only messages with "field_0" > 10 and "field_2" != "test"
sdf = sdf[(sdf["field_1"] > 10) & (sdf["field_2"] != "test")]

# Filter messages using custom functions
sdf = sdf[sdf.apply(lambda value: 0 < (value['field_1'] + value['field_3']) < 1000)]

# Generate a new value based on the current one
sdf = sdf.apply(lambda value: {**value, 'new_field': 'new_value'})

# Update a value based on the entire message content
sdf['field_4'] = sdf.apply(lambda value: value['field_1'] + value['field_3'])

# Use a stateful function to persist data to the state store and update the value in place
sdf = sdf.update(count, stateful=True)

# Print the result before producing it
sdf = sdf.update(lambda value, ctx: print('Producing a message:', value))

# Produce the result to the output topic 
sdf = sdf.to_topic(output_topic)

if __name__ == "__main__":
    # Run the streaming application

How It Works

There are two primary components:

  • StreamingDataFrame - a predefined declarative pipeline to process and transform incoming messages.
  • Application - to manage the Kafka-related setup & teardown and message lifecycle (consuming, committing). It processes each message with the dataframe you provide it.

Under the hood, the Application will:

  • Consume a message.
  • Deserialize it.
  • Process it with your StreamingDataFrame.
  • Produce it to the output topic.
  • Automatically commit the topic offset and state updates after the message is processed.
  • React to Kafka rebalancing updates and manage the topic partitions.
  • Manage the State store.
  • Handle OS signals and gracefully exit the application.


To see Quix Streams in action, check out the Quickstart and Tutorials in the docs:

Using the Quix Cloud

This library doesn't have any dependency on any commercial products, but if you use it together with Quix Cloud you will get some advantages out of the box during your development process such as:

  • Auto-configuration.
  • Monitoring.
  • Data explorer.
  • Data persistence.
  • Pipeline visualization.
  • Metrics.

and more.

Quix Streams provides a seamless integration with Quix Cloud, and it can automatically configure the Application using Quix SDK Token.

Please see the Connecting to Quix Cloud page to learn how to use Quix Streams and Quix Cloud together.

What's Next

This library is being actively developed.

Here are some of the planned improvements:

To find out when the next version is ready, make sure you watch this repo and join our Quix Community on Slack!

Contribution Guide

Contributing is a great way to learn and we especially welcome those who haven't contributed to an OSS project before.
We're very open to any feedback or code contributions to this OSS project ❤️.

Before contributing, please read our Contributing file for how you can best give feedback and contribute.

Need help?

If you run into any problems, please create an issue or ask in #quix-help in our Quix Community on Slack.

Community 👭

Join the Quix Community on Slack, a vibrant group of Python developers, data enthusiasts and newcomers to Apache Kafka, who are learning and leveraging Quix Streams for real-time data processing.


Quix Streams is licensed under the Apache 2.0 license. View a copy of the License file here.

Stay in touch 👋

You can follow us on Twitter and Linkedin where we share our latest tutorials, forthcoming community events and the occasional meme.

If you have any questions or feedback - write to us at!

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