# README

Stomper

A message broker implementing the STOMP protocol written in Go.

Examples

I have written a simple chat client designed to use a generic STOMP pub-sub server called stomp-chat that can serve as an example of a client for this server.

Currently one simple point-to-point messaging example is included at examples/PointToPoint. Clone the repo, navigate to that folder, and run docker-compose up to see it in action.

Install and test latest build from GHCR

Pull Docker image from the GHCR:

$ docker pull ghcr.io/tydar/stomper:main

Run and publish the port from the example config:

$ docker run -d -p 32801:32801 ghcr.io/tydar/stomper:main

Connect with a STOMP client at port 32801 and test!

To overwrite Stomper's default settings, you can pass environment variables to the container:

$ docker run -d -p 32801:32801 --env STOMPER_TOPICS="/queue/env1 /queue/env2" ghcr.io/tydar/stomper:main

Nix build support

This project contains a minimal default.nix. To build the Stomper using Nix, you should follow these steps:

On NixOS, ensure you are working with Go installed: nix-shell -p go.
Run go mod vendor in the project directory.
Run nix build.

Configuration options

Parameter	ENV variable	Default Value	Description
Port	STOMPER_PORT	32801	TCP port server listens on
Hostname	STOMPER_HOSTNAME	localhost	hostname on which server accepts connections
TCPDeadline	STOMPER_TCPDEADLINE	0	TCP timeout (time in seconds allowed between msg from client, 0 means no timeout)
LogPath	STOMPER_LOGPATH	./stomper.log	path to log file
LogToFile	STOMPER_LOGTOFILE	true	should we stomper log to a file?
LogToStdout	STOMPER_LOGTOSTDOUT	false	should stomper log to stdout?
Topics	STOMPER_TOPICS	["/queue/main"]	list of pub-sub topics
SendWorkers	STOMPER_SENDWORKERS	1	Number of send worker goroutines to spawn
MetricsServer	STOMPER_METRICSSERVER	false	should we expose a JSON metrics endpoint?
MetricsAddress	STOMPER_METRICSADDRESS	":8080"	address string for Metrics Service ListenAndServe call

An example config file is provided: stomper_config.yaml. Stomper will look for a file with this name in either /etc/stomper or the directory from which it is called.

Notes beyond STOMP specification

Creating a topic with a message
- If a SUBSCRIBE frame includes a header with key create and value true, it will create the topic if it does not already exist.

Done

Frame parsing
Define interface for queueing
Implement memory queue backend
Frame handling
- CONNECT
- SUBSCRIBE
- UNSUBSCRIBE
- SEND
- MESSAGE
- RECEIPT
- ERROR
- DISCONNECT
- BEGIN
- COMMIT
- ABORt
Semantics
- Supports only pub-sub currently
runtime topic creation by clients
Configuration of worker pool for message forwarding