msgscript

README

Table of Contents

• Features
• Installation
  • Outside NixOS
• Dependencies
• Usage
  • Adding Scripts
  • Writing Lua Scripts
• Contributing
• Support

msgscript is primarily a Go server that runs Lua functions internally based on NATS subjects.

Features

• Single binary
• Nearly no overheads
• Good enough performances (RTT of around 10ms for the hello example)
• Runs Lua functions based on NATS subjects
• Integrates with etcd for script storage

Installation

msgscript is primarily designed to be used with Nix and NixOS (this is my personal use case). You can enable it in your NixOS configuration using the provided module:

services.msgscript.enable = true;

The options are defined in the nix/modules/default.nix file.

Outside NixOS

Being a standalone Go binary, you can build each of the binaries like so:

go build ./cmd/server # Generates the server binary
go build ./cmd/cli    # Generates the cli binary

Dependencies

The server requires:

• etcd
• NATS

Ensure these services are running and accessible to the msgscript server. The server and cli can see the NATS_URL and ETCD_ENDPOINTS environment variables on top of the flags -etcdurl and -natsurl.

Usage

Adding Scripts

You can add Lua scripts to etcd using the msgscriptcli command. Here's an example:

msgscriptcli -subject funcs.pushover -name pushover ./examples/pushover.lua

This command adds the pushover.lua script from the examples directory, associating it with the subject funcs.pushover and the name pushover.

Writing Lua Scripts

When writing Lua scripts for msgscript, you have access to additional modules:

• db: SQL access to MySQL, Sqlite3 and PostgreSQL
• http: For making HTTP requests
• json: For JSON parsing and generation
• lfs: LuaFilesystem implementation
• nats: For publishing messages back to NATS
• re: Regular expression library
• Various modules from the gopher-lua-libs

Some examples scripts are provided in the examples folder.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Support

If you encounter any problems or have any questions, please open an issue on the GitHub repository.