VacationPlanner

A small Go API that generates vacation itineraries through langchaingo using OpenAI-compatible providers (OpenAI and OpenRouter).

The app exposes two endpoints:

• POST /Vacation/create to start generating a vacation idea.
• GET /Vacation/:id to fetch generation status and result.

Generation runs asynchronously in a goroutine, so you create first and then poll by ID.

Tech Stack

• Go
• Gin (github.com/gin-gonic/gin) for HTTP routing
• LangChainGo (github.com/tmc/langchaingo) with OpenAI provider
• UUIDs via github.com/google/uuid

Project Structure

VacationPlanner/
|-- main.go
|-- go.mod
|-- go.sum
|-- .gitignore
|-- chains/
|   |-- structs.go
|   `-- vacations.go
`-- routes/
    |-- structs.go
    `-- vacations.go

How It Works

1. Client sends vacation preferences to POST /Vacation/create.
2. API returns a generated UUID immediately with completed: false.
3. Background goroutine calls an OpenAI-compatible provider using langchaingo.
4. Generated itinerary is saved in memory and marked completed: true.
5. Client polls GET /Vacation/:id until completed.

Prerequisites

• Go installed (project go.mod declares go 1.25.0)
• A valid API key with available quota:
  • OpenAI key, or
  • OpenRouter key

Run Locally

From project directory:

cd C:\Users\ujjan\Music\Go\VacationPlanner
set "OPENAI_API_KEY=YOUR_OPENAI_KEY"
go run main.go

OpenRouter test example:

cd C:\Users\ujjan\Music\Go\VacationPlanner
set "OPENROUTER_API_KEY=YOUR_OPENROUTER_KEY"
set "OPENROUTER_MODEL=openai/gpt-4o-mini"
go run main.go

Server starts at:

http://localhost:8080

API Usage

1. Create Vacation Idea

Request:

POST /Vacation/create
Content-Type: application/json

Body:

{
  "favourite_season": "summer",
  "hobbies": ["hiking", "photography"],
  "budget": 1500
}

curl (cmd.exe):

curl -X POST http://localhost:8080/Vacation/create -H "Content-Type: application/json" -d "{\"favourite_season\":\"summer\",\"hobbies\":[\"hiking\",\"photography\"],\"budget\":1500}"

Example response:

{
  "id": "c1e0f8d0-48a3-4b2e-a4ee-25dcf58c69d0",
  "completed": false
}

2. Poll Result by ID

Request:

GET /Vacation/:id

curl:

curl http://localhost:8080/Vacation/c1e0f8d0-48a3-4b2e-a4ee-25dcf58c69d0

Possible responses:

• While processing:

{
  "id": "c1e0f8d0-48a3-4b2e-a4ee-25dcf58c69d0",
  "completed": false,
  "idea": ""
}

• After completion:

{
  "id": "c1e0f8d0-48a3-4b2e-a4ee-25dcf58c69d0",
  "completed": true,
  "idea": "..."
}

Environment Variables

• OPENROUTER_API_KEY (optional, preferred for OpenRouter): if set, the app routes requests through OpenRouter.
• OPENROUTER_MODEL (optional): defaults to openai/gpt-4o-mini.
• OPENROUTER_BASE_URL (optional): defaults to https://openrouter.ai/api/v1.
• OPENAI_API_KEY (optional fallback): used when OPENROUTER_API_KEY is not set.
• OPENAI_MODEL (optional): defaults to gpt-4o-mini.
• PORT (optional): Gin defaults to 8080 when not set.

Security Notes

• Never commit API keys.
• Keep keys in environment variables or untracked local files like .env.
• If a key is exposed, rotate/revoke it immediately.
• .gitignore is configured to exclude common secret and local artifact files.

Troubleshooting

• OPENROUTER_API_KEY or OPENAI_API_KEY is not set
  • Set one of those variables in the same terminal session before go run.
• OpenAI generation error: ... 429 ... exceeded your current quota
  • Billing/quota issue in OpenAI account or project.
  • Add credits/payment method, confirm project budget, then use a valid key.
• completed stays false
  • Check server logs right after POST /Vacation/create for the real generation error.

Current Limitations

• Data is stored in memory (Vacations slice) and is lost on restart.
• No persistence/database layer.
• No synchronization for concurrent writes to shared in-memory slice.
• No auth/rate limiting for public endpoints.

Suggested Next Improvements

1. Add persistent storage (PostgreSQL or SQLite).
2. Add mutex protection around shared in-memory data if kept.
3. Add structured error field in API response for failed generation jobs.
4. Add tests for routes and chain logic.
5. Add Dockerfile and .env.example for easier setup.