UA-Orchestrator

A command-line tool for automating OPC UA node interactions using a CSV action script. Built with Rust, it connects to an OPC UA server and executes a sequence of read, write, and wait operations defined by the selected CSV file.

Overview

This tool connects to an OPC UA server using credentials and security settings defined in a TOML configuration file. Once connected, it reads a CSV file of actions and executes them in order — reading node values, writing values, waiting for user input, or polling until a node reaches a target value.

Getting Started

Prerequisites

• Rust toolchain (cargo)
• Access to an OPC UA server

Build

cargo build --release

Configure

Copy the example configuration file and fill in your server details:

cp Config.example.toml Config.toml

Edit Config.toml:

server_url = "opc.tcp://your-server:4840"
server_security_policy = "Basic256Sha256"
server_security_mode = "SignAndEncrypt"
username = "your_username"
password = "your_password"

Supported security policies: None, Basic128Rsa15, Basic256, Basic256Sha256

Supported security modes: None, Sign, SignAndEncrypt

Prepare your CSV action file

Copy the example CSV and customise it:

cp actions.example.csv actions.csv

Usage

Run the binary and optionally pass the path to your CSV file as an argument:

./ua-orchestrator actions.csv

If no path is provided, the tool will prompt you to enter one interactively.

CSV Action Format

The CSV file must have the following columns:

action, tag, value, sleep

Column	Description
action	The operation to perform (see table below)
tag	The OPC UA node identifier string (namespace index 2)
value	Optional value used by write/wait actions
sleep	Milliseconds to wait after the action completes

Actions

Action	Description
read	Reads and prints the current value of the node
write	Writes value to the node
user_write	Prompts the user for input (uses value as a pre-fill if provided), then writes to the node
comment	Prints tag as a label/message in the terminal
wait	Pauses execution and waits for the user to press Enter
wait_until	Polls the node until its value equals value, then continues
# ...	Lines whose action begins with # are treated as in-script comments and skipped

Value Type Inference

Values in the CSV are automatically parsed into the appropriate OPC UA Variant type:

Input	Type
$*	String where $ is dropped
true / false (case-insensitive)	Boolean
Integer string (e.g. 42)	Int64
Floating-point string (e.g. 3.14)	Double
Anything else	String

Example CSV

action,     tag,               value, sleep
comment,    Starting sequence, ,      0
write,      MyNode.SetPoint,   100,   500
read,       MyNode.SetPoint,   ,      0
write,      MyNode.SSN,        $0100, 500
read,       MyNode.SetPoint,   ,      0
wait_until, MyNode.Status,     1,     250
comment,    Done,              ,      0

PKI / Certificates

On first run, a self-signed certificate and private key are automatically generated for the current OS user. They are stored at:

./pki/own/     ← user certificate
./pki/private/ ← private key

The server's certificate is automatically trusted (trust_server_certs = true). If your server requires manual trust configuration, add the generated certificate to the server's trusted store.

Project Structure

File	Description
main.rs	Entry point: loads config, parses args, starts OPC UA session, runs CSV
config.rs	Deserialises Config.toml; maps policy/mode strings to OPC UA types
actions.rs	CSV row definition, value parsing, per-row action dispatch, run_csv loop
opc_ua_client.rs	OpcUaClient trait, OpcUaSession with read/write batching, LiveSessionBackend
globals.rs	Centralised string messages, magic values, and path constants
reader.rs	InputReader trait and StdinReader implementation
Config.example.toml	Template configuration file - copy to Config.toml before use
actions.example.csv	Template action script - copy to actions.csv before use

Running Tests

Unit tests cover value parsing, action dispatch, and OPC UA session read/write behaviour using in-memory fakes (no live server required):

cargo test

Deployment Note

If the compiled binary is moved to a system or environment without OpenSSL 4 installed, the following OpenSSL DLLs must be present either in the same directory as the executable or somewhere on the system PATH:

• libcrypto-4-x64.dll
• libssl-4-x64.dll

Copyright

Copyright 2026 Merck KGaA, Darmstadt, Germany and/or its affiliates. All rights reserved.