weather

Weather Server Example

An MCP server that demonstrates HTTP client usage, caching, and metrics tracking.

What This Example Demonstrates

• Enabling cache for responses
• Cache key management
• Cache hit/miss tracking
• Multiple tools
• Metrics collection and reporting
• Graceful shutdown with metrics logging

Features

• get_weather: Get current weather for a city (cached for 5 minutes)
• get_forecast: Get 3-day forecast for a city

Note: This example returns mock data. In a real implementation, you would use srv.HTTPClient() to call an actual weather API.

Running the Example

go run main.go

Testing

Call the same city twice to see caching in action:

// First call - cache miss
{"city": "San Francisco"}

// Second call within 5 minutes - cache hit
{"city": "San Francisco"}

Metrics

The server tracks and reports:

• Tool invocations
• Cache hits and misses
• Cache hit rate
• Uptime

Metrics are logged on shutdown.

Real Implementation

To integrate with a real weather API:

// Use the HTTP client
type WeatherResponse struct {
    Temperature float64 `json:"temp"`
    Condition   string  `json:"condition"`
}

var result WeatherResponse
err := srv.HTTPClient().Get(ctx, 
    "https://api.weather.com/v1/current?city="+input.City,
    &result)
if err != nil {
    return nil, nil, fmt.Errorf("weather API error: %w", err)
}

Next Steps

• Add more weather-related tools (alerts, historical data)
• Implement actual API integration
• Add error handling for API failures
• Use different cache TTLs for different data types

See the fileserver example for resource usage.