Quickstart: LangChainGo with OpenAI

Get started by running your first program with LangChainGo and OpenAI. OpenAI's GPT models are renowned for their proficiency and expansive capabilities.

Prerequisites

1. OpenAI API Key: Sign up on OpenAI and retrieve your API key.
2. Go: Download and install Go.

Setup

Before interacting with the OpenAI API, you need to set up your API key as an environment variable.

Linux/macOS (bash/zsh)

export OPENAI_API_KEY="your_openai_api_key_here"

Windows (Command Prompt)

set OPENAI_API_KEY=your_openai_api_key_here

Windows (PowerShell)

$env:OPENAI_API_KEY="your_openai_api_key_here"

For permanent setup, add the environment variable to your shell's profile file (~/.bashrc, ~/.zshrc, etc.) or system environment variables on Windows.

Steps

1. Set up your OpenAI API Key: Follow the setup instructions above to configure your API key.

2. Run the example: Execute the following command:

go run github.com/tmc/langchaingo/examples/openai-completion-example@main

You should see output similar to the following:

The first man to walk on the moon was Neil

Congratulations! You have successfully built and executed your first LangChainGo LLM-backed program using OpenAI's cloud-based inference.

Here is the entire program (from openai-completion-example):

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/tmc/langchaingo/llms"
	"github.com/tmc/langchaingo/llms/openai"
)

func main() {
	llm, err := openai.New()
	if err != nil {
		log.Fatal(err)
	}
	ctx := context.Background()
	completion, err := llms.GenerateFromSinglePrompt(ctx,
		llm,
		"The first man to walk on the moon",
		llms.WithTemperature(0.8),
		llms.WithStopWords([]string{"Armstrong"}),
	)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println("The first man to walk on the moon:")
	fmt.Println(completion)
}