Quote System - a stock-quote streaming system

Two applications for generating and receiving stock quotes in real time:

• quote_server - generates quotes and broadcasts them to clients over UDP
• quote_client - connects to the server and receives quotes

Project structure

quote_system/
├── Cargo.toml              # Workspace
├── common/                 # Shared library (StockQuote, StreamCommand, constants)
│   ├── src/lib.rs
│   └── tests/
│       └── integration_test.rs
├── server/                 # quote_server binary crate
│   └── src/
│       ├── main.rs         # TCP server, dispatcher, PING monitor
│       └── generator.rs    # Quote generator (random walk)
├── client/                 # quote_client binary crate
│   └── src/main.rs         # TCP client, UDP receive, PING send
├── tickers.txt             # Example tickers file
└── README.md

Build

cargo build --release

Running the tests

cargo test --workspace

Running

1. Start the server

RUST_LOG=info cargo run --release -p quote_server

Or with parameters:

RUST_LOG=info cargo run --release -p quote_server -- \
    --bind-addr 0.0.0.0:7878 \
    --generation-interval-ms 100 \
    --ping-timeout-secs 5

2. Start the client

RUST_LOG=info cargo run --release -p quote_client -- \
    --server-addr 127.0.0.1:7878 \
    --udp-port 34254 \
    --tickers-file tickers.txt

Server arguments

Argument	Default	Description
--bind-addr	0.0.0.0:7878	TCP server address and port
--generation-interval-ms	100	Quote generation interval (ms)
--ping-timeout-secs	5	Timeout for waiting on a client PING (s)

Client arguments

Argument	Default	Description
--server-addr	127.0.0.1:7878	TCP server address
--udp-port	34254	Local port for receiving UDP
--tickers-file	tickers.txt	Path to the file with the ticker list

Protocol

The STREAM command (TCP)

STREAM udp://<ip>:<port> <TICKER1>,<TICKER2>,...

Example: STREAM udp://127.0.0.1:34254 AAPL,TSLA,GOOGL

Server response:

• OK - the stream has started
• ERR <message> - an error (invalid command, malformed address, etc.)

Quote data (UDP)

JSON format:

{"ticker":"AAPL","price":175.23,"volume":3456,"timestamp":1234567890}

Keep-Alive (UDP)

• The client sends PING every 2 seconds to the server's UDP socket
• If the server does not receive a PING within 5 seconds (configurable), the stream is stopped

Architecture

Server (threads)

• Generator thread - produces quotes for all 100+ tickers and sends them into a channel
• Dispatcher thread - receives quotes from the channel and distributes them to subscribed clients
• PING monitor thread - checks client timeouts and removes inactive ones
• TCP handler thread - one per incoming TCP connection
• UDP sender thread - one per active client

crossbeam-channel (mpmc) is used for inter-thread communication.

Client (threads)

• Main thread - receives UDP data and prints quotes to the console
• PING thread - periodically sends PING to the server

Ticker file format

One ticker per line. Empty lines and whitespace are ignored.

AAPL
GOOGL
TSLA