Demo
This folder contains examples for the connectors to the different stream processing systems that are currently provided in the Scotty open source project.
The connectors that can be found in the different modules implement the interface of the WindowOperator and depend on the stream processing system. They are essential to use Scotty as a window aggregator within the API of the respective system.
Each subfolder within this directory provides the resources necessary to run an example of a stream processing pipeline on one of the stream processing systems with Scotty as a window operator.
The subfolders provide the following components:
Demo files
The demo files contain the stream processing pipelines that use Scotty as a window operator within the stream processing system.
Demo Source
Each subfolder provides an implementation for a demo source that continuously generates tuples with arbitrary values to resemble a data stream. In these demos the tuples consist of two attributes, a key and a value. However, the records could have multiple attributes of different data types.
Window Functions
For each of the connectors window aggregation functions such as sum, min, max, quantile are given. The window functions have to implement one of the interfaces of the windowFunction folder in the core module. They depend on the tuples and their attributes. Thus, they have to be adjusted based on the stream. The user can extend Scotty with window functions beyond these examples as needed.
Window types
Scotty provides different implementations for window types such as the tumbling window, sliding window, session window and fixed-band window. Scotty enables to add multiple window types to the window operator, so that multiple different concurrent windows are applies onto the stream. When assigning these window types, one can choose different window configurations. It is possible to change the measure (time measure or count measure), the window size, window slide for sliding windows or session gap for session windows. Window types are provided in the core module of Scotty. It is possible to extend Scotty with user-defined window types as needed.
Flink Demo
The Flink subfolder presents three different examples that utilize Scotty as a window operator within the Flink API. The demo files provide Flink pipelines that are almost identical, but with minor modifications. This exemplifies how to change the window types and window functions. The FlinkSumWindowDemo uses a sum aggregation as the window function. This example shows how to assign three different window types to the window operator. Here, the tumbling window, sliding window and session window are used. To change this up, the FlinkQuantileDemo applies the quantile window function onto the stream. A third demo adjusts the tumbling window to be of count-based measure.
Similarly, one can adjust the other demo files to try out different window functions, window types or window configurations.
Demo Requirements for Samza, Kafka, Spark
- Apache Zookeeper host:localhost , port:2181
- Apache Kafka Server host:localhost , port:9092
Demo Usage:
- Start Zookeeper
- Start Kafka Server
- Start SparkSumDemo.java
Note: There are separate modules for each system within this folder to prevent incompatibilties between the different system versions. For instance, dependencies on the connectors to Flink and Spark together in one module could cause errors due to different scala versions.