Chatbot that works on the top of Ollama

chatbot.go

package main

import (
	"bufio"
	"bytes"
	"encoding/json"
	"flag"
	"fmt"
	"net/http"
	"os"
	"strings"
)

type Message struct {
	Role string `json:"role"`
	Content string `json:"content"`
}

// RequestToModel is what we send to the model
type RequestToModel struct {
	Model string `json:"model"`
	Message []Message `json:"messages"`
}

type ReplyFromModel struct {
	Choices []Choice `json:"choices"`
}

type Choice struct {
	Message Message `json:"message"`
}

func main() {
	model := flag.String("model", "qwen2.5:0.5b", "model name to chat with")
	flag.Parse()

	conversation := []Message{
		{
			Role: "system",
			Content: "You are a concise, friendly assistant",
		},
	}

	reader := bufio.NewReader(os.Stdin)
	fmt.Printf("Chatting with %s. Type 'quit' to exit.\n", *model)

	for {
		fmt.Print("\nyou > ")
		line, _ := reader.ReadString('\n')
		line = strings.TrimSpace(line)
		if line == "quit" || line == "" {
			return
		}

		// add the message to the converation
		conversation = append(conversation, Message{Role: "user", Content: line})
		
		// send the conversation to the model
		reply, err := ask(*model, conversation)
		if err != nil {
			fmt.Println("error:", err)
			continue
		}

		conversation = append(conversation, reply)
		fmt.Printf("bot > %s\n", reply.Content)
	}
}

// ask sends the conversation to the model and returns the models' reply message
func ask(model string, conversation []Message) (Message, error) {
	request := RequestToModel{
		Model: model,
		Message: conversation,
	}

	body, _ := json.Marshal(request)

	resp, err := http.Post("http://localhost:11434/v1/chat/completions", "application/json", bytes.NewReader(body))
	if err != nil {
		return Message{}, err
	}
	defer resp.Body.Close()

	// Decode the JSON that comes back into our ReplyFromModel shape.
	var incoming ReplyFromModel
	if err := json.NewDecoder(resp.Body).Decode(&incoming); err != nil {
		return Message{}, err
	}
	if len(incoming.Choices) == 0 {
		return Message{}, fmt.Errorf("no reply from model")
	}
 
	// Hand back the first (and usually only) answer.
	return incoming.Choices[0].Message, nil
}