python driver psycopg3

[mhmaguire]

Updated python driver code to psycopg 3 for my own purposes and figured you all might like to do the same sometime.

[aked21]

Hi @mhmaguire, can you specify what have been changed and/or added for your needs?
Thank you for contributing! AK

[dehowef]

Wow! Thank you so much this is great.

[mhmaguire]

@aked21 I attempted to change as little as possible and swap psycopg2 for v3. That being said some changes were necessary as psycopg3 introduces a new type adaptation system, no longer has an ext module, and doesn't have a replacement implementation for execute_values:

• drivers/python/age/age.py
  • Loader subclass to cast ag_type. AgeLoader decodes bytes and passes the string to parseAgeValue.
  • It's unclear if it is necessary to implement a Dumper as well?
  • Additionally we can rely on TypeInfo.fetch(typename) to fetch type details from pg.
  • cursor_factotry=ClientCursor in Age constructor so that we have access to .mogrify().
  • unsure why previous implementation did this: cypher = cypher[2:len(cypher)-1] For me this was mangling the produced cypher statements so replaced with cypher = cypher.strip()
• drivers/python/networkx/lib.py
  • execute_values in networkx/lib.py replaced with executemany
• Misc
  • updated all type hints
  • ensure tests pass
  • updated tests so parsed args actually get passed to Age constructor
  • ensure notebooks work

[dehowef]

@mhmaguire I pulled down your changes to take a look, and the test files are complaining with the line:

AttributeError: 'TestAgeBasic' object has no attribute 'args'

Granted I just took a cursory glance, but I wanted to ask, do the tests work on your machine? Thanks for your time.

[dehowef]

@mhmaguire scratch my previous comment-- User error on my part! I'll continue reviewing this when I find a moment

[dehowef]

@mhmaguire scratch my previous comment-- User error on my part! I'll continue reviewing this when I find a moment

Lol okay actually sorry to walk back my comment again, but when I run the unittests via "python -m unittest -v test_age_.py" and python -m unittest -v test_networkx.py as stated in the documentation, they throw an attribute error as follows:

Traceback (most recent call last): File "/home/user/age/drivers/python/test_age_py.py", line 36, in setUp host=self.args.host, ^^^^^^^^^ AttributeError: 'TestAgeBasic' object has no attribute 'args'

The unit tests still run fine if I call them directly, but I think it'd be a relatively easy fix to get this error to disappear. Would you mind amending your commit so that they work with these unit test commands? Otherwise it looks great and I appreciate what you've done here. I think after that change, I'll give it another once over and probably good to go. @mhmaguire

[mhmaguire]

@dehowef I set a default prefilled namespace so tests won't fail when bypassing argparse.

python test_age_py.py would have a similar effect...

[dehowef]

@dehowef I set a default prefilled namespace so tests won't fail when bypassing argparse.

python test_age_py.py would have a similar effect...

@mhmaguire Yeah, that way of testing was written by the original author of the python driver, been thinking of updating/removing that section of the documentation. I just looked over everything, and it looks great! We usually want to bring all updates to the main branch down to previous versions, from PG16 down til PG13. If you want to create the PRs for those branches as well, feel free to, otherwise I might just go ahead and do that within the next few days!! Thank you so much for your contribution :slightly_smiling_face: