uaView

A lightweight, terminal-based OPC-UA client for seamless server interaction.

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Introduction

uaView is a lightweight, terminal-based user interface (TUI) designed for efficient interaction with OPC-UA servers. It allows users to connect, browse nodes, and monitor live data in real-time — all within an intuitive command-line environment.

Features

• Easy Connection Management: Quickly connect to OPC-UA servers via a simple selection interface.
• Project Organization: Save server configurations for better project management.
• Address Space Browser: Navigate the server's address space in a tree-like structure.
• Node Details: View comprehensive node attributes in a structured table format.
• Real-time Monitoring: Subscribe to nodes to see live value updates with timestamps.
• Activity Logging: Monitor operations and events in real-time.
• Dark Mode Support: Eye-friendly interface for long sessions.
• Keyboard Shortcuts: Navigate efficiently using keyboard-driven controls.
• Cross-Platform: Compatible with Linux, macOS, and Windows.

Why uaView?

uaView addresses the need for a lightweight, terminal-based OPC-UA client, especially useful for:

• Terminal-focused workflows (SSH, headless servers, containers)
• Quick access to server information without GUI overhead
• Keyboard-driven navigation for faster operation
• Managing multiple server connections across projects
• Resource-constrained environments

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Installation

uaView can be run via Docker or Docker Compose. By default, the application looks for settings.json inside the container at /app/config/settings.json. Using the UAVIEW_SETTINGS environment variable is optional and only needed if you want to load the settings from a different path.

1. Docker Run (Default Way)

Run the container using the default internal settings path:

docker run -it \
  --name uaview \
  -v <HOST_PATH_TO_SETTINGS_JSON>:/app/config/settings.json \
  uaview_local:0.0.1 \
  bash

• The app automatically loads /app/config/settings.json inside the container.
• No UAVIEW_SETTINGS environment variable is required.
• Replace <HOST_PATH_TO_SETTINGS_JSON> with the path to your local settings.json.

Optional: To use a custom path for the settings file, set the UAVIEW_SETTINGS environment variable:

docker run -it \
  --name uaview \
  -e UAVIEW_SETTINGS=/custom/path/settings.json \
  -v /home/user/custom_settings.json:/custom/path/settings.json \
  uaview_local:0.0.1 \
  bash

Common Error: Container Name Conflict

If you see the following error:

docker: Error response from daemon: Conflict. The container name "/uaview" is already in use by container "<container_id>". You have to remove (or rename) that container to be able to reuse that name.

Solution:

• Remove the old container:

docker rm uaview

• Or use a different container name:

docker run -it --name uaview_test ...

• Alternatively, use the --rm option to automatically remove the container when it exits, avoiding conflicts:

docker run --rm -it \
  -e UAVIEW_SETTINGS=/app/config/settings.json \
  -v /home/user/uaview_test/settings.json:/app/config/settings.json \
  uaview_local:0.0.1 \
  bash

This is recommended for temporary or interactive use.

2. Docker Compose (Default Way)

version: "3.9"
services:
  uaview:
    image: uaview_local:0.0.1
    container_name: uaview
    volumes:
      - <HOST_PATH_TO_SETTINGS_JSON>:/app/config/settings.json
    tty: true
    stdin_open: true

Optional: To override with a custom settings path, add:

    environment:
      - UAVIEW_SETTINGS=/custom/path/settings.json

Usage:

1. Save as docker-compose.yml.
2. Run docker-compose up.
3. Enter the container shell with docker exec -it uaview bash.

Notes

• Ensure the host path to settings.json is absolute, e.g., /home/user/uaview/settings.json.
• The default internal path inside the container is /app/config/settings.json.
• Using Docker Compose is recommended for reproducible deployments or multi-container setups.
• Using --rm with docker run avoids container name conflicts for interactive sessions.

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Configuration

Server connections are configured in uaView/config/settings.json.

Example Configuration

{
  "Local Test Server": {
    "endpoint_url": "opc.tcp://localhost:4840/freeopcua/server/",
    "security_policy": "None",
    "security_mode": "None",
    "user_name": "",
    "password": ""
  },
  "Production Server": {
    "endpoint_url": "opc.tcp://192.168.1.100:4840/UA/ProductionServer",
    "security_policy": "Basic256Sha256",
    "security_mode": "SignAndEncrypt",
    "user_name": "admin",
    "password": "secure_password"
  },
  "Cloud Server": {
    "endpoint_url": "opc.tcp://cloud.example.com:4840/",
    "security_policy": "Basic256Sha256",
    "security_mode": "Sign",
    "user_name": "readonly_user",
    "password": "view_only_pass"
  }
}

Parameters:

• endpoint_url: OPC-UA server endpoint URL.
• security_policy: Security policy (None, Basic256, Basic256Sha256).
• security_mode: Security mode (None, Sign, SignAndEncrypt).
• user_name / password: Optional credentials; leave empty for anonymous access.

Security Tips:

• Store sensitive credentials securely.
• Use environment variables or Docker secrets for production.

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Usage

Key Bindings

Key	Action	Description
Tab	Next view	Cycle through interface panels
↑/↓	Navigate	Move through tree/list items
←/→	Collapse/Expand	Toggle tree nodes
Enter	Select	Select highlighted item
s	Subscribe	Subscribe to node for live updates
d	Toggle dark mode	Switch light/dark theme
q	Quit	Exit the application
?	Help	Show command palette

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Limitations

• Historical Data: Not yet supported.
• Methods: Cannot invoke server methods.
• Write Operations: Read-only mode.
• Event Monitoring: Event subscriptions not implemented.
• Certificate Management: Limited support.
• Batch Operations: No bulk subscribe/unsubscribe.
• Export: Data export not yet available.

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Contributing

Contributions are welcome! Submit a Pull Request or open an issue for discussion. See CONTRIBUTING for details.

License

Licensed under the MIT License. See LICENSE for details.

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Made with ❤️ for the OPC UA community.