Running opennsa on debian 12 fails due to error on twistar library: re.error global flags not at the start

[italovalcy]

Hi,

After fixing other building errors like the one reported in #44, the following error happens after starting opennsa in Debian 12 I get the following error:

2024-05-08 20:57:30Z [-] Unhandled error in Deferred:
2024-05-08 20:57:30Z [-] Unhandled Error
	Traceback (most recent call last):
	  File "/usr/local/lib/python3.11/dist-packages/twisted/internet/defer.py", line 662, in _runCallbacks
	    current.result = callback(current.result, *args, **kw)
	  File "/usr/local/lib/python3.11/dist-packages/twisted/internet/base.py", line 515, in _continueFiring
	    callable(*args, **kwargs)
	  File "/usr/local/lib/python3.11/dist-packages/twisted/internet/defer.py", line 1656, in unwindGenerator
	    return _cancellableInlineCallbacks(gen)
	  File "/usr/local/lib/python3.11/dist-packages/twisted/internet/defer.py", line 1571, in _cancellableInlineCallbacks
	    _inlineCallbacks(None, g, status)
	--- <exception caught here> ---
	  File "/usr/local/lib/python3.11/dist-packages/twisted/internet/defer.py", line 1445, in _inlineCallbacks
	    result = current_context.run(g.send, result)
	  File "/home/opennsa/opennsa/opennsa/backends/common/genericbackend.py", line 89, in buildSchedule
	    conns = yield GenericBackendConnections.find(where=['source_network = ? AND dest_network = ? AND lifecycle_state <> ?', self.network, self.network, state.TERMINATED])
	  File "/usr/local/lib/python3.11/dist-packages/twistar/dbobject.py", line 427, in find
	    d = config.select(klass.tablename(), id, where, group, limit, orderby)
	  File "/usr/local/lib/python3.11/dist-packages/twistar/dbobject.py", line 364, in tablename
	    klass.TABLENAME = inf.tableize(klass.__name__)
	  File "/usr/local/lib/python3.11/dist-packages/BermiInflector/Inflector.py", line 78, in tableize
	    return self.Inflector.tableize(class_name)
	  File "/usr/local/lib/python3.11/dist-packages/BermiInflector/Rules/Base.py", line 80, in tableize
	    return self.pluralize(self.underscore(class_name))
	  File "/usr/local/lib/python3.11/dist-packages/BermiInflector/Rules/English.py", line 66, in pluralize
	    match = re.search(rules[rule][0], word, re.IGNORECASE)
	  File "/usr/lib/python3.11/re/__init__.py", line 176, in search
	    return _compile(pattern, flags).search(string)
	  File "/usr/lib/python3.11/re/__init__.py", line 294, in _compile
	    p = _compiler.compile(pattern, flags)
	  File "/usr/lib/python3.11/re/_compiler.py", line 743, in compile
	    p = _parser.parse(p, flags)
	  File "/usr/lib/python3.11/re/_parser.py", line 980, in parse
	    p = _parse_sub(source, state, flags & SRE_FLAG_VERBOSE, 0)
	  File "/usr/lib/python3.11/re/_parser.py", line 455, in _parse_sub
	    itemsappend(_parse(source, state, verbose, nested + 1,
	  File "/usr/lib/python3.11/re/_parser.py", line 841, in _parse
	    raise source.error('global flags not at the start '
	re.error: global flags not at the start of the expression at position 1

[Joshua-M-CANARIE]

Having delved further into this. Here's the source of the error:
Debian image stable-slim has moved to Bookworm which uses python version 3.11, whereas the original OpenNSA build used Bullseye, using python version 3.9, and the package twistar does not support version 3.11

In python 3.11, they require using a tag at the beginning of regex, like (?s) or (?i), which the twistar library does not do.

As it stands, the latest version of twistar is version 2.0.0, which is the version used by OpenNSA, and it was released back in 2018 and the git hub repo has been archived by the owner back in 2021. It appears very, very unlikely that Twistar will be updated to use Python 3.11 on its own, so there's 3 options at this point.

• Build the image using explicitly Bullseye from debian:bullseye-slim
• Refactor the OpenNSA library to not make use of Twistar
• Create a fork of Twistar and update it to support version 3.11

In my development, migrating back to Bullseye has proven successful, however this solution won't support all requirements, particularly once Bullseye reaches EOL in 2026.

[italovalcy]

Hi @Joshua-M-CANARIE thanks a lot for checking this. I've a running version of opennsa and BerlinInflector lib running on debian 12 with the following change:

sed -i 's/\^(?i)(ox)/(?i)^(ox)/g' /usr/local/lib/python3.11/dist-packages/BermiInflector/Rules/English.py

I think the best option would be Refactor the OpenNSA library to not make use of Twistar. However, since I this. seems to be a long path, maybe maintaining a fork of BermiInflector or Twistar. I can help on that if you guys are interested.