Java SDK for Numaflow

This SDK provides the interface for writing UDFs and UDSinks in Java.

Usage

For usage, see examples.

You will see a warning in the log on startup, which you can safely ignore:

Oct 25, 2022 12:26:30 PM io.netty.bootstrap.AbstractBootstrap setChannelOption
WARNING: Unknown channel option 'SO_KEEPALIVE' for channel '[id: 0x6e9c19c7]'

This is due to grpc-netty trying to set SO_KEEPALIVE when it shouldn't (https://github.com/grpc/grpc-java/blob/47ddfa4f205d4672e035c37349dfd3036c74efb6/netty/src/main/java/io/grpc/netty/NettyClientTransport.java#L237) .

Runtime Requirements

• java 11+
• x86_64 linux

OS other than x86_64 linux can be supported with minor changes, ref: https://netty.io/wiki/native-transports.html. Consider building for multiple OS if needed. Once grpc-netty depends on netty 5+, consider requiring newer java ( ref: netty/netty#10991).

Build Requirements

• java 11+
• maven 3.6+

Build

mvn clean install

Updating proto definition files

To keep up-to-date, do the following before building:

• copy the *.proto files from numaflow-go into /src/main/proto
• replace the go_package lines with the following java_package:

option java_package = "io.numaproj.numaflow.function.v1";

option java_package = "io.numaproj.numaflow.sink.v1";

Code Style

Use Editor Config.