RankingService

Summary

RankingService is a Spring Boot-based microservice that acts as an aggregator for the user point management system. Its primary role is to provide a unified view of users and their accumulated points. It does not maintain its own database; instead, it orchestrates calls to the UserService and PointService to fetch user identities and point balances, respectively, and then merges this data into a single response.

Project Flow

The project follows an aggregator pattern to provide ranking data:

1. Request Handling Layer (RankController): Receives incoming REST requests with a minPoint threshold.
2. Service Layer (RankingService & UserPointService):
   • User Data Fetching: Calls the UserService to retrieve a complete list of registered users (IDs and Names).
   • Point Data Fetching: Calls the PointService to retrieve point data for users who meet the specified minPoint criteria.
   • Data Aggregation: Uses internal mapping logic to correlate the user IDs returned by the PointService with the user names fetched from the UserService.
3. Data Models: Uses Google Protocol Buffers (Protobuf) for internal messaging and for the API request/response structures.

API Endpoints

The API uses application/json as the media type and returns Protobuf-based structures.

Endpoint	Method	Description	Input	Output
/rank/users	POST	Retrieves a list of users and their points, filtered by a minimum threshold.	GetUserRankRequest	GetUserRankResponse

API Details

1. Get User Rank Data

• Path: /rank/users
• Method: POST
• Input (GetUserRankRequest):

  {
    "minPoint": integer
  }

• Output (GetUserRankResponse):

  {
    "userPointList": [
      {
        "name": "string",
        "point": integer
      }
    ]
  }

• Process:
  1. Fetch all users from UserService.
  2. Fetch all users meeting the minPoint criteria from PointService.
  3. Aggregate the results by matching IDs to Names.

Technology Stack

• Framework: Spring Boot 4.0.3
• Serialization: Google Protocol Buffers (Protobuf)
• Inter-service Communication: OkHttp 5
• Build Tool: Gradle (Kotlin DSL)
• Deployment: Kubernetes (YAML files included in k8s/ directory)
• Containerization: Docker (Dockerfile included)

Configuration

The service relies on external service configurations (injectable via environment variables):

• UserService:
  • USER_SERVICE_HOST: Hostname for the UserService (default: userservice.userservicenamespace)
  • userservice.path: Path for fetching all users (default: /users)
• PointService:
  • POINT_SERVICE_HOST: Hostname for the PointService (default: pointservice-svc.psn)
  • pointservice.path: Path for fetching point data (default: /point/users)

The application runs on port 8093 by default.

Inter-Service Dependencies

• UserService: Required to resolve user IDs into human-readable names.
• PointService: Required to retrieve the current point balances for users.