s03.go•3.5 kB
// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// SPDX-License-Identifier: Apache-2.0
package main
import (
"context"
"slices"
"github.com/firebase/genkit/go/ai"
"github.com/firebase/genkit/go/genkit"
"google.golang.org/genai"
)
type chatSessionInput struct {
SessionID string `json:"sessionID"`
Question string `json:"question"`
}
type chatSessionOutput struct {
SessionID string `json:"sessionID"`
History []*ai.Message `json:"history"`
}
// Very simple local storage for chat history.
// Each conversation is identified by a sessionID generated by the application.
// The history has a preamble of message, which serves as a system prompt.
type chatHistory []*ai.Message
type chatHistoryStore struct {
preamble chatHistory
sessions map[string]chatHistory
}
func (ch *chatHistoryStore) Store(sessionID string, history chatHistory) {
ch.sessions[sessionID] = history
}
func (ch *chatHistoryStore) Retrieve(sessionID string) chatHistory {
if h, ok := ch.sessions[sessionID]; ok {
return h
}
return ch.preamble
}
func setup03(g *genkit.Genkit, m ai.Model) error {
chatPreamblePrompt := genkit.DefinePrompt(g, "s03_chatPreamble",
ai.WithMessages(
ai.NewUserTextMessage("Hi. What's on the menu today?"),
ai.NewModelTextMessage(`
I am Walt, a helpful AI assistant here at the restaurant.
I can answer questions about the food on the menu or any other questions
you have about food in general. I probably can't help you with anything else.
Here is today's menu:
{{#each menuData~}}
- {{this.title}} \${{this.price}}
{{this.description}}
{{~/each}}
Do you have any questions about the menu?`),
),
ai.WithModel(m),
ai.WithInputType(dataMenuQuestionInput{}),
ai.WithOutputFormat(ai.OutputFormatText),
ai.WithConfig(&genai.GenerateContentConfig{
Temperature: genai.Ptr[float32](0.3),
}),
)
menuData, err := menu(&ai.ToolContext{Context: context.Background()}, nil)
if err != nil {
return err
}
preamble, err := chatPreamblePrompt.Render(context.Background(), map[string]any{
"menuData": menuData,
"question": "",
})
if err != nil {
return err
}
storedHistory := &chatHistoryStore{
preamble: chatHistory(preamble.Messages),
sessions: make(map[string]chatHistory),
}
genkit.DefineFlow(g, "s03_multiTurnChat",
func(ctx context.Context, input *chatSessionInput) (*chatSessionOutput, error) {
history := storedHistory.Retrieve(input.SessionID)
msg := &ai.Message{
Content: []*ai.Part{
ai.NewTextPart(input.Question),
},
Role: ai.RoleUser,
}
messages := append(slices.Clip(history), msg)
resp, err := genkit.Generate(ctx, g, ai.WithModel(m), ai.WithMessages(messages...))
if err != nil {
return nil, err
}
messages = append(messages, resp.Message)
storedHistory.Store(input.SessionID, messages)
out := &chatSessionOutput{
SessionID: input.SessionID,
History: messages,
}
return out, nil
},
)
return nil
}