is it possible to prevent alembic upgrade from working unless the database has been initialized with alembic stamp?
#1716
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is it possible to prevent I adopted Alembic on a project with multiple deployments. Some nodes received an emergency manual hotfix of sql code, and don't need the first alembic migration. These fail and need a manual cleanup if the new Alembic code gets deployed to them. I'd just like to fail |
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Replies: 2 comments 6 replies
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Hi, I don't think you want stamp, since that will write the head migration(s) to the version tables, so that afterward no other migration will be run, since alembic sees them as already fully applied |
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well stamp can apply any version you want to the table |
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by default it doesn't sound it stamp head though? |
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Probably sure |
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The initialization script invokes “stamp head” the underlying ask though, is to ensure the alembic integration has been properly onboarded. Some nodes will require a revision, others will require no revision. writing that makes me think I could have approached this differently- is there a way to require an explicit “no base revision”? |
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you can look for alembic version table in env.py using |
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Brilliant! Thank you so much. The ‘inspect’ in I just want to ensure the DB has been initialized for alembic before upgrade can run. Stamp initalizes to a specific version and seemed to be invoked implicitly by the other functions so I focused on it, |
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Just cross referencing this post with #1705 |
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you can look for alembic version table in env.py using
inspect(connection).has_table("alembic_version"). for stamp you'd need to check if some version that you expect is in the table, we dont exactly have an "is_version_applied" method, you'd need to look at what version is present and then walk the revision tree to see if it's a descendant of the version you expect, if that's what you really want here. look in the source for the ";history" command to see how to get this data