vowpal_wabbit_in_daemon.go

package main

import (
	"bufio"
	"fmt"
	"log"
	"net"
)

// mac: brew install vowpal-wabbit
// start daemon:
// vw --daemon --foreground --port 58009 --num_children 1 --oaa 2 --loss_function=logistic
func main() {
	conn, err := net.Dial("tcp", "127.0.0.1:58009")
	if err != nil {
		log.Fatal(err)
	}
	r := bufio.NewReader(conn)

	for i := 0; i < 5; i++ {
		fmt.Println("-----")
		s := ""
		if i%2 == 0 {
			s = "1 | anal\n"
		} else {
			s = "2 | oral\n"

		}
		_, err := conn.Write([]byte(s))
		if err != nil {
			log.Fatal(err)
		}

		bin, err := r.ReadBytes(byte(10))
		if err != nil {
			log.Fatal(err)
		}
		if len(bin) > 0 {
			bin = bin[:len(bin)-1]
		}

		fmt.Println("send", s, "recv", string(bin))
	}

	result, err := predict(conn, r, "| anal\n")
	fmt.Println("predict anal", result)

	result, err = predict(conn, r, "| oral\n")
	fmt.Println("predict oral", result)

	err = saveModel(conn, r)
	if err != nil {
		log.Fatal(err)
	}

	err = conn.Close()
	if err != nil {
		log.Fatal(err)
	}
}

func saveModel(conn net.Conn, r *bufio.Reader) error {
	_, err := conn.Write([]byte("save_filemodel.vw"))
	if err != nil {
		return err
	}

	return err
}

func predict(conn net.Conn, r *bufio.Reader, line string) (string, error) {
	_, err := conn.Write([]byte(line))
	if err != nil {
		return "", err
	}
	bin, err := r.ReadBytes(byte(10))
	if err != nil {
		return "", err
	}
	if len(bin) > 0 {
		bin = bin[:len(bin)-1]
	}
	return string(bin), nil
}