44 lines
1.6 KiB
Python
44 lines
1.6 KiB
Python
"""backups: record when a configuration was last confirmed unchanged.
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Dedup means an unchanged config writes NO revision, so `collectedat` moves only
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when something changes. A machine whose settings have been stable for six months
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therefore has a six-month-old newest revision and is entirely healthy - and
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ShopDB had no way to tell it apart from a machine whose backup stopped running
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six months ago. The evidence that a check happened existed only in a log file on
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the PC.
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`lastseenat` records the check rather than the change. It is touched on every
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matching post, including the no-op that writes nothing else.
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Backfilled from `collectedat` (falling back to `createdat`) so existing rows
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start from the last moment we can actually prove the config was current, rather
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than from now - claiming a fresh check that never happened would be worse than
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saying nothing.
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"""
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from alembic import op
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import sqlalchemy as sa
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# revision identifiers, used by Alembic.
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revision = 'backups0002lastseenat'
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down_revision = 'backups0001baseline'
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branch_labels = None
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depends_on = None
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def upgrade():
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columns = {c['name'] for c in
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sa.inspect(op.get_bind()).get_columns('backuprevisions')}
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if 'lastseenat' not in columns:
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op.add_column('backuprevisions',
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sa.Column('lastseenat', sa.DateTime(), nullable=True))
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op.execute('UPDATE backuprevisions '
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'SET lastseenat = COALESCE(collectedat, createdat)')
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def downgrade():
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columns = {c['name'] for c in
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sa.inspect(op.get_bind()).get_columns('backuprevisions')}
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if 'lastseenat' in columns:
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op.drop_column('backuprevisions', 'lastseenat')
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