Request flows

The information is available in the HDL Flow diagrams and in the sequence diagrams:

1. Weather Data Update Flow (every 5 minutes)

Purpose

This flow describes how new weather data from the provider is ingested, processed, and stored in the system.

Actors and Systems

Weather Info Provider (WIP): The external source of weather data.
Kafka Current (KC): The message bus (Kafka topic) for current weather events.
Current Weather Processor MS (P): Microservice that processes new weather data.
S3 Bucket (S3): Storage for weather JSON files (the source of truth for served data).

Steps

Publish Event:
The Weather Info Provider publishes a new current weather event to the Kafka Current topic.
WIP ->> KC: Publish current weather event
Consume Event:
The Current Weather Processor Microservice consumes the event from Kafka.
P ->> KC: Consume weather event
Process Data:
The processor microservice processes and formats the new weather data.
P ->> P: Process & format weather data
Update Storage:
The processed weather data is written as an updated JSON file in the S3 bucket.
P ->> S3: Write updated weather JSON

2. Get Current Weather Flow (User request)

Purpose

This flow details how a user retrieves current weather information for a city/location, including how the system leverages CDN caching for performance.

Actors and Systems

User (U): The end-user searching for weather information.
Client App (C): Web or mobile application interface.
DNS: Resolves the service endpoint.
CDN: Content Delivery Network that caches and serves weather JSON files.
S3 Bucket (S3): Origin storage for weather JSON files.

Steps

User Search:
The user initiates a search for weather information for a specific city or location in the client application.
U ->> C: Search weather for city/location
DNS Resolution:
The client app requests DNS resolution for the weather service URL.
C ->> DNS: Resolve weather service URL
DNS -->> C: Return CDN endpoint
Weather Request:
The client app sends an HTTPS request to the CDN for the weather data.
C ->> CDN: GET /cities/{city_code}/current-weather.json
Cache Decision:
- If the CDN has the data cached:
- The CDN responds immediately with the cached weather JSON.
- CDN -->> C: Return cached weather JSON
- If the CDN does not have the data cached (cache miss):
  - The CDN fetches the JSON file from S3.
  - CDN ->> S3: Fetch JSON file
  - S3 -->> CDN: Return weather JSON
  - The CDN then responds to the client app with the fresh weather JSON.
  - CDN -->> C: Return fresh weather JSON
Show to User:
The client app displays the received weather information to the user.
C -->> U: Show current weather

Submissions

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Submissions

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