Artwork by Ashley McNamara - Inspired by Renee French - Taken from https://gopherize.me by Mat Ryer

A native Go implementation of the OPC/UA Binary Protocol.

# install library
go get -u github.com/gopcua/opcua

# get current date and time 'ns=0;i=2258'
go run examples/datetime/datetime.go -endpoint opc.tcp://localhost:4840

# read the server version
go run examples/read/read.go -endpoint opc.tcp://localhost:4840 -node 'ns=0;i=2261'

# get the current date time using different security and authentication modes
go run examples/crypto/*.go -endpoint opc.tcp://localhost:4840 -cert path/to/cert.pem -key path/to/key.pem -sec-policy Basic256 -sec-mode SignAndEncrypt

# checkout examples/ for more examples...

We are still actively working on this project and the APIs will change.

However, you can safely assume that we are aiming to make the APIs as stable as possible. :)

• ERR messages are bubbled up to the caller
• security protocol support. See https://github.com/gopcua/opcua/wiki/Supported-Devices to get a list of devices/applications we have tested various crypto and authentication methods. Please add your own. See examples/crypto for an example.
• Debug messages are now disabled by default.

We are getting closer to use this for our first production use cases. Subscription support is certainly high on the list for the client as is a Server implementation. Let us know what is missing right now to make this library useful for you and we can focus on this first.

Our goal is to make this the native Go library for OPC/UA.

This code is not ready for production but we intend to get it there.

We are testing the code against real-world PLCs and other OPC/UA implementations but this needs to be more formalized. The goal is to have the examples working with real PLCs. Please let us know if they don't.

We are working on the library and some things are working but others are not.

Here is what currently works:

• client connection handshake, create secure channel and session
• async request/response dispatching on the secure channel
• support for chunking when receiving (not sending)
• all structures and enums are generated from official OPC Foundation defintions
• basic uasc listener available but no server implementation
• start of a high-level Client implementation. See client.go and examples/datetime for a usage example.
• decent tests of the binary protocol codec

Here is what is not yet working:

• ERR messages are not yet bubbled up to the caller (not hard but need to do it)
• service calls need to check ServiceStatus and bubble that error up (also not hard)
• no security protocol support. @dwhutchinson provided the crypto code but it needs to be integrated into the network layer.
• no high-level server implementation, address space, etc.

If you are looking for ways to contribute you can

• test the high-level client against real OPC/UA servers
• add functions to the client or tell us which functions you need for gopcua to be useful
• work on the security layer, server and other components
• and last but not least, file issues, review code and write/update documentation

Also, if the library is already useful please spread the word as a motivation.

The Gopcua Team.

The current focus is on the OPC UA Binary protocol over TCP. No other protocols are supported at this point.

The current set of supported services is only for the high-level client.

MIT