open62541 VS pymgclient

Zip trees are great!

For a project I made a version that uses the memory location of the entries to construct the (random) rank on the fly.

So it’s a binary tree structure that requires the same memory as a linked list (two pointers) only!

https://github.com/open62541/open62541/blob/master/deps/zipt...

Here is a bug report I submitted to open62541, over a year ago. Figuring out how that library works... I don't even understand the terminology; it's all very generic (everything is called 'nodes', 'objects', etc.), there are loads of ways to do anything, type safety is not a concept the library approves of so that doesn't help either, and most functions you cannot even find in the source as they are generated by macros. It doesn't help that OPC UA is a big standard (thousands of pages) either. It boggles the mind that the reference implementation for something used in so many critical places is so badly documented, and at the same time allows so many ways to get things subtly wrong.

There's quite a bit of OPC UA bashing across this project. So let me chime in to keep the "balance in the universe".

OPC UA is a protocol to interact with an object-oriented information model. Basically CORBA done right to use object-oriented principles and reuse software components in industrial automation.

Since OPC UA is a protocol, its performance depends mostly on the implementation. Some PLCs may be crappy. But that doesn't translate into bad performance overall. My experience goes to the exact contrary.

Full disclosure, I lead-develop and maintain an open source OPC UA implementation that sees quite a bit of use by the big guys in the automation domain. We use C for performance. And we do have funding from the industry.

https://github.com/open62541/open62541

But yes, it is hard to break into this world. Especially since solutions have to be maintained for 20+ years. A solo developer usually cannot ensure that this will still be usable some years down the line.

Earlier this year I was trying to use open62541, and ended up writing this bugreport. The developers are, so far, ignoring it, and it's a crying shame because it makes the library so much less useful than it could otherwise be.

Why don't you use a standardized industrial protocol, that support these requirements? Would perhaps OPC UA meet your needs? There are a number of open source implementations and the standard itself is open, too.

FROM python:3.8 # Install CMake RUN apt-get update && \ apt-get --yes install cmake # Install mgclient RUN apt-get install -y git cmake make gcc g++ libssl-dev && \ git clone https://github.com/memgraph/mgclient.git /mgclient && \ cd mgclient && \ git checkout dd5dcaaed5d7c8b275fbfd5d2ecbfc5006fa5826 && \ mkdir build && \ cd build && \ cmake .. && \ make && \ make install # Install pymgclient RUN git clone https://github.com/memgraph/pymgclient /pymgclient && \ cd pymgclient && \ python3 setup.py build && \ python3 setup.py install # Install packages COPY requirements.txt ./ RUN pip3 install -r requirements.txt COPY card_fraud.py /app/card_fraud.py WORKDIR /app ENV FLASK_ENV=development ENV LC_ALL=C.UTF-8 ENV LANG=C.UTF-8 ENTRYPOINT ["python3", "card_fraud.py"]

As expected, Flask is there, so it will be installed in our container. Next, we have pymgclient, Memgraph database adapter for Python language on top of which gqlalchemy is built. We will connect to the database with gqlalchemy and it will assist us in writing and running queries on Memgraph.