⬆️ UPGRADE: sqlalchemy v1.4 (v2 API)

[chrisjsewell]

Currently based on top of #113, supersedes #108

Following migration: https://docs.sqlalchemy.org/en/14/changelog/migration_20.html

• Added SQLALCHEMY_WARN_20 environmental variable
• Use future=True for engine and session creation (V1 -> v2 API)
• query -> select (V1 -> v2 API)
• Rename models.py -> database.py (models is too generic does not describe the module's purpose)
• Moved get_session -> database.py (this method can be independent of the container)
• Added mypy extension: https://docs.sqlalchemy.org/en/14/orm/extensions/mypy.html

I noted the count() method is now a bit more complex, but this is explained in: sqlalchemy/sqlalchemy#6794

A few things to double-check:

• A number of queries used with_entities, but I was unclear why this was necessary,
  i.e. I changed query(Obj)...with_entities(Obj.hashkey) to select(Obj.hashkey).. @giovannipizzi any reason why this would be an issue?

• Vacuum now fails, since it is in a transaction. I've added a workaround, but checked on this in: How to perform a vacuum? sqlalchemy/sqlalchemy#6959 (comment)

[codecov]

Codecov Report

Merging #114 (848a95b) into develop (c0a67a3) will decrease coverage by 0.12%.
The diff coverage is 97.50%.

@@             Coverage Diff             @@
##           develop     #114      +/-   ##
===========================================
- Coverage    99.68%   99.56%   -0.13%     
===========================================
  Files            7        7              
  Lines         1585     1601      +16     
===========================================
+ Hits          1580     1594      +14     
- Misses           5        7       +2     

Impacted Files	Coverage Δ
disk_objectstore/container.py	99.39% <95.34%> (-0.25%)	⬇️
disk_objectstore/database.py	100.00% <100.00%> (ø)
disk_objectstore/utils.py	99.60% <100.00%> (-0.01%)	⬇️

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[ramirezfranciscof]

Everything great here 👍🏽 I just have one question out of curiosity but this is ready to merge for me.

[ramirezfranciscof]

What is the difference between session.execute(text("COMMIT")) and session.commit() and why is it necessary to make it differently here? (I imagine it has to do with the comment of different transactions but why)

[chrisjsewell]

The difference is that this direct execution bypasses sqlalchemy’s auto-transaction mechanics, and stops it from starting a new transaction before executing the vacuum (which cannot be executed within a transaction)

[chrisjsewell]

Cheers!