USB external import, and filter chips on health-dot cards

plugins/usb/migrations/versions/0003_checkout_scan_fields.py

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+"""Record whether a returned drive was virus-scanned.
+
+The external cmmc_usb checkinoutlog carries scanned_viruses and sanitized on
+every row. The self-hosted usbcheckouts table already has waswiped, which is
+the same fact as sanitized under a different name, but nothing corresponds to
+scanned_viruses. That gap was harmless while the two backends were
+alternatives, and becomes data loss the moment a site imports its history and
+cuts over: whether a returned drive was scanned is precisely what a
+removable-media audit asks.
+
+Nullable on purpose, and NOT defaulted to false. A checkout recorded before
+this column existed is not a checkout where the drive went unscanned; it is one
+where nobody wrote it down. False would assert something the data does not say.
+
+Idempotent, so a re-run on an already-migrated database is a no-op.
+
+Revision ID: usb0003scanfields
+Revises: usb0002dropmachineid
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = 'usb0003scanfields'
+down_revision = 'usb0002dropmachineid'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    if 'usbcheckouts' not in insp.get_table_names():
+        return
+    cols = {c['name'] for c in insp.get_columns('usbcheckouts')}
+    if 'scannedviruses' not in cols:
+        op.add_column('usbcheckouts',
+                      sa.Column('scannedviruses', sa.Boolean(), nullable=True))
+
+
+
+def downgrade():
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    if 'usbcheckouts' not in insp.get_table_names():
+        return
+    cols = {c['name'] for c in insp.get_columns('usbcheckouts')}
+    if 'scannedviruses' in cols:
+        op.drop_column('usbcheckouts', 'scannedviruses')