tinypubsub

tinypubsub is a minimal, in-memory TCP-based publish–subscribe server written in Go. This is a toy project built to explore Go concurrency, channels, and event-driven design.

There is no persistence and no durability. Restarting the server resets all state.

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Features

• TCP server using Go’s net package
• Simple text-based protocol
• In-memory topic subscriptions
• Fan-out message delivery using Go channels
• Single event loop for state mutation

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Build

make build

This builds the binary at:

./bin/tinypubsub

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Run

./bin/tinypubsub

The server listens on port 9000.

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Usage

Connect using nc (netcat):

nc localhost 9000

Commands

SUB <topic>          Subscribe to a topic
UNSUB <topic>        Unsubscribe from a topic
PUB <topic> <msg>    Publish a message to a topic
LIST                 List subscribed topics
EXIT                 Close the connection

Example

SUB sports
PUB sports hello world
LIST
UNSUB sports
EXIT

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Notes

• All state is in-memory
• No authentication
• No persistence
• Not safe for production use

This project exists purely for learning and experimentation.