MQTT370

MQTT370 is an MQTT client, broker, and CLI for IBM MVS 3.8j, originally created by Michael Dean Rayborn. It provides MQTT 5.0 messaging capabilities for applications running on Hercules-emulated MVS systems.

This project is maintained as part of the mvslovers community.

Components

• client/ — MQTT client library (connect, publish, subscribe)
• broker/ — MQTT message broker with Lua-based configuration
• cli/ — Command-line interface for MQTT operations
• utility/ — Shared utility functions (encoding, networking, etc.)

Building

Prerequisites

• Cross-compilation environment for MVS 3.8j
• c2asm370 compiler (GCC-based, targeting S/370)
• mvsasm assembler script
• CRENT370 libraries by Mike Rayborn

Clone

git clone --recursive https://github.com/mvslovers/mqtt370.git
cd mqtt370

Configuration

Copy .env.example to .env and set your MVS host credentials and dataset names:

cp .env.example .env
# edit .env with your values

Compile

make            # build all components
make clean      # clean all components

To build a single component:

make -C client
make -C broker
make -C cli
make -C utility

The build pipeline is: C source → c2asm370 → S/370 Assembly (.s) → mvsasm → Object decks (.o) → MVS datasets.

Project Structure

client/src/     MQTT client library source files
broker/src/     MQTT broker source files
cli/src/        CLI tool source files
utility/src/    Shared utility source files
include/        Header files (shared across all components)
contrib/        Git submodules (SDK headers for dependencies)
scripts/        Build helper scripts
doc/            Documentation

Acknowledgments

This project was created by Michael Dean Rayborn, whose extensive work on MVS 3.8j tooling forms the foundation of the entire MVS open-source ecosystem.

License

This project is licensed under the MIT License.