How to establish connection with kafka server in Rust - tcp

Question

I'm trying to establish connection with kafka server without third party libraries in Rust.
This is the description of kafka server TCP protocol
This is my code:
fn connect() -> Result<(), std::io::Error> {
let stream = TcpStream::connect("localhost:9092").expect("Could not connect");
let mut input_stream = stream.try_clone().unwrap();
input_stream.set_read_timeout(Some(Duration::new(5, 0)));
input_stream.set_write_timeout(Some(Duration::new(5, 0)));
/// HERE IS MY PROBLEM. I DON'T KNOW HOW TO ENCODE KAFKA MESSAGE
let mut data = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
/// api key 0, 0, 0, 0, 0, 0
/// request_api_version 0, 0, 0, 0, 0, 0
/// correlation_id 0, 0, 0, 0, 0, 0,
let mut buffer: Vec<u8> = Vec::with_capacity(1400);
buffer.extend_from_slice(&[0; 100]);
input_stream.write(&mut data)?;
match input_stream.read(&mut buffer) {
Ok(b) => {
println!("read ok - {:?}", String::from_utf8_lossy(&buffer));
}
Err(e) => println!("Error {}", e),
}
Ok(())
}
fn main() {
connect();
}
How to encode this kafka message to byte array ?
Variable data should be an array of bytes

Answer 1

Naive code for creating kafka message of next interface
request_api_key => INT16
request_api_version => INT16
correlation_id => INT32
const int16 = (prevBuffer: Buffer, value: number) => {
const newBuffer = Buffer.alloc(2)
newBuffer.writeInt16BE(value)
return Buffer.concat([prevBuffer, newBuffer]);
}
const int32 = (prevBuffer: Buffer, value: number) => {
const newBuffer = Buffer.alloc(4)
newBuffer.writeInt32BE(value)
return Buffer.concat([prevBuffer, newBuffer]);
}
const payload = int31(int16(int16(Buffer.alloc(0), 3), 0),1);
The code is shamelessly taken from kafkajs