Requirements

Functional Requirements:

• System should retrieve current weather data for specified locations.
• Users can specify a location and receive the latest weather data.
• Weather details should include temperature, humidity, weather conditions, etc.
• The user can specify units of measurement.
• The system has support for real-time updates of data.

Non-Functional Requirements:

• 99.9% uptime/availability
• <2s non-cached requests, <500ms cached requests
• 10k concurrent users, can accommodate demand spikes due to severe weather events.
• Weather data is consistent and updated regularly

API Design

• GET /weather/?location=<location>&units=<metric>

Response:

• POST /weather

Request:

• POST /subscribe

Request:

Response:

High-Level Design

WeatherService:

• Weather data per location
  • GET /weather?location=<location>&unit=<metric>
• Populates data with external APIs
  • See Weather Data Providers section
• Responsible for converting data into unified format
• Caches recent API calls for reduced latency based on location.
  • GET /weather?location=<location>&unit=<metric>
  • GET /forecast?location=<location>&unit=<metric>

Real-Time Update Engine:

• WebSockets in combination with publisher/subscriber pattern.
• Client's open a WebSocket connection and subscribe to updates for a given location.
• When the server receives weather updates for a given location, it pushes the update to all current subscribers of that location. (Weather updates can also be pushed on a scheduled basis.

Weather Data Providers:

• Third-Party Data Providers
  • AccuWeather
  • The Weather Company
• Data Ingestion
  • REST APIs
  • Batch File uploads
  • Real-time data feeds
• Data format

Detailed Component Design

RealTimeUpdateService

• Publisher/Subscriber pattern for real-time updates.

WeatherDataService

• API for returning detailed weather data per location.