PoW Quotes Server

The PoW Quotes Server is a Go-based microservice that serves quotes while employing a Proof of Work (PoW) system to prevent abuse. It uses the Gin framework for routing HTTP requests.

Features

• Proof of Work (PoW) Challenge: Clients must solve a PoW challenge to retrieve quotes, preventing spam by requiring computational work for each request.
• Adaptive Difficulty: The PoW challenge difficulty adjusts based on request volume within a set timeframe.
• Quotes Database Management: Capable of loading quotes from a JSON file into a persistent database.

Endpoints

• GET /api/v1/pow/: Returns data for the PoW challenge, including a random number, a token, and the leading zeros count.
• GET /api/v1/quotes/: Retrieves quotes from the database, requiring a valid PoW token.

Running the Server

Without Docker

Ensure Go is installed and perform the following:

1. Change to the server's directory.
2. Install dependencies with go mod tidy.
3. Launch the server with go run main.go and the necessary flags.

With Docker

Just run command:

docker compose up --build

in a root directory of the project.

Configuration Flags

-leadingZerosUpdateInterval int  # Update interval for leading zeros (default 1)
-port string                     # Server port (default "8080")
-quotesJsonPath string           # Path to quotes JSON file
-requestsThreshold int           # Request threshold for PoW calculation (default 1)
-timeFrame int                   # Time frame for requests count (default 20)

PoW Quotes Client

The client interacts with the PoW Quotes Server, solving the PoW challenge and fetching quotes using the obtained token.

Configuration Flag

-baseUrl string  # Base URL of the quotes server (default "http://localhost:8080")

Running the Client

Without Docker

With Go installed:

1. Change to the client's directory.
2. Install dependencies.
3. Execute go run main.go with the server's base URL as a flag.

With Docker

Just run command:

docker compose up --build

In a root directory of the project.

Than you can use the client inside the container.

docker exec -it <container_id> /bin/sh

Or you still can build the client and run it on your local machine, because server port is exposed.

Docker Compose Example

Below is a docker-compose.yml snippet for running the server:

version: '3'

services:
  quotes-server:
    build: ./quotes-server # path to server Dockerfile
    ports:
      - "8080:8080"
    volumes:
      - ./quotes-server/quotes.json:/app/quotes.json # Volume for quotes.json file
    command: >
      sh -c "go run main.go
      -leadingZerosUpdateInterval 1
      -port 8080
      -quotesJsonPath /app/quotes.json
      -requestsThreshold 1
      -timeFrame 20"
    depends_on:
      - quotes-client

  quotes-client:
    depends_on:
      - quotes-server
    build: ./quotes-client # path to client Dockerfile
    command: >
      sh -c "go run main.go
      -baseUrl http://quotes-server:8080"

This docker-compose setup ensures that the server and client are deployed together and can communicate effectively.