Aoba

Multi-protocol debugging and simulation CLI/TUI tool for Modbus RTU

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Multi-protocol debugging and simulation tool for Modbus RTU, suitable for both physical serial ports and network-forwarded ports. Provides both CLI and TUI interfaces.

Features

• Modbus RTU (master/slave) debugging and simulation; supports four register types: holding, input, coils, and discrete.
• Full-featured CLI: port discovery and checks (--list-ports / --check-port), master/slave operations (--master-provide / --slave-listen) and persistent modes (--*-persist). Outputs can be JSON/JSONL, which is script/CI-friendly.
• Interactive TUI: configure ports, stations, and registers via terminal UI; supports save/load (Ctrl+S saves and auto-enables ports) and IPC integration with CLI for testing and automation.
• Multiple data sources and protocols: physical/virtual serial ports (managed via socat), HTTP, MQTT, IPC (Unix domain sockets / named pipes), files, and FIFOs.
• Port Forwarding: configure source and target ports within the TUI for data replication, monitoring, or bridging.
• Daemon mode: run headless using a saved TUI configuration to start all configured ports/stations (suitable for embedded/CI deployments).
• Virtual port and test tooling: includes scripts/socat_init.sh for virtual serial ports and example tests in examples/cli_e2e and examples/tui_e2e for local/CI testing.
• Extensible integrations: forward or receive port data via HTTP/MQTT/IPC for (remote) integrations.

Note: use --no-config-cache to disable TUI save/load; --config-file <FILE> and --no-config-cache are mutually exclusive.

Quick start

1. Install the Rust toolchain

2. Clone the repo and enter the directory

3. Install:

   • Build from source: cargo install aoba

   • Or install a CI-built release (if available) with cargo-binstall:

     • Example: cargo binstall --manifest-path ./Cargo.toml --version <version>

     • Use --target <triple> to pick a platform-specific artifact (e.g. x86_64-unknown-linux-gnu).

4. Run aoba to start the TUI by default; use TUI to configure ports and save the configuration as needed.

Persistent configuration (config file)

--config-file <FILE> explicitly selects a TUI config file (daemon mode uses --daemon-config <FILE>). This conflicts with --no-config-cache, which disables loading/saving of TUI config.

Example:

# Start TUI with a specific config file; load/save enabled
aoba --tui --config-file /path/to/config.json

# Start TUI with no config caching (default) — no load/save
aoba --tui --no-config-cache

Run headless with a saved configuration:

aoba --daemon --config-file /path/to/config.json

Systemd example:

[Unit]
Description=Aoba Modbus RTU Daemon
Wants=network.target
After=network.target network-service
StartLimitIntervalSec=0

[Service]
Type=simple
WorkingDirectory=/home/youruser
ExecStart=/usr/local/bin/aoba --daemon --config-file /home/youruser/config.json
Restart=always
RestartSec=1s

[Install]
WantedBy=multi-user.target

Common use cases

• Automated testing: auto-start Modbus simulators in CI/CD
• Embedded systems: run Aoba as a daemon on embedded devices (e.g., Raspberry Pi) with USB-serial adapters

Programmatic API

Aoba provides a trait-based Rust API for embedding Modbus functionality in your applications. The API supports both master (client) and slave (server) roles with customizable hooks and data sources.

Quick API Examples

Modbus Master (polling a slave):

use aoba::api::modbus::{ModbusBuilder, RegisterMode};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    // Create and start a master that polls a slave
    let master = ModbusBuilder::new_master(1)
        .with_port("/dev/ttyUSB0")
        .with_register(RegisterMode::Holding, 0, 10)
        .build_master()?;

    // Receive responses via iterator interface
    while let Some(response) = master.recv_timeout(std::time::Duration::from_secs(2)) {
        println!("Received: {:?}", response.values);
    }
    Ok(())
}

Modbus Slave (responding to requests):

use aoba::api::modbus::{ModbusBuilder, RegisterMode};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    // Create and start a slave that responds to master requests
    let slave = ModbusBuilder::new_slave(1)
        .with_port("/dev/ttyUSB0")
        .with_register(RegisterMode::Holding, 0, 10)
        .build_slave()?;

    // Receive request notifications via iterator interface
    while let Some(notification) = slave.recv_timeout(std::time::Duration::from_secs(10)) {
        println!("Processed request: {:?}", notification.values);
    }
    Ok(())
}

Manual Mode (write operations + single-shot polling):

use aoba::api::modbus::{ModbusBuilder, RegisterMode};

fn main() -> anyhow::Result<()> {
    let master = ModbusBuilder::new_master(1)
        .with_port("/dev/ttyUSB0")
        .with_timeout(5000)
        .build_master_manual()?;

    // Single-shot poll
    let resp = master.poll_once(RegisterMode::Holding, 0, 10)?;
    println!("Values: {:?}", resp.values);

    // Write single holding register (fc 0x06)
    master.write_holding(0x00, 0x1234)?;

    // Write multiple holding registers (fc 0x10)
    master.write_registers(0x00, &[0x1234, 0x5678])?;

    // Write coils (fc 0x0F)
    master.write_coils(0x00, &[true, false, true])?;

    Ok(())
}

Running the API Examples

Method 1: Using the test script (recommended)

A Python test script is provided to run both master and slave examples simultaneously with colored, prefixed output:

# Run for 30 seconds
python3 scripts/run_api_test.py --duration 30

# Run indefinitely (Ctrl+C to stop)
python3 scripts/run_api_test.py

# Custom ports
python3 scripts/run_api_test.py --master-port /dev/ttyUSB0 --slave-port /dev/ttyUSB1

# Skip auto-build (use existing binaries)
python3 scripts/run_api_test.py --no-build

Note: You may see "Operation timed out" warnings in the logs. This is normal behavior:

• The slave times out while waiting for master requests (1s timeout)
• The master times out while waiting for slave responses (2s timeout)
• Both automatically retry and continue operation
• Communication succeeds despite these warnings

Method 2: Manual execution

Run in separate terminals:

# Terminal 1: Start slave first
cargo run --package api_slave -- /tmp/vcom2

# Terminal 2: Start master
cargo run --package api_master -- /tmp/vcom1

Note: On Linux/WSL, initialize virtual serial ports first:

./scripts/socat_init.sh

Complete Examples

For full examples with middleware hooks and data sources, see:

• examples/api_master - Master with logging hooks
• examples/api_slave - Slave with request monitoring and statistics

License

Licensed under the Synthetic Source License (SySL), Version 1.0.