fix(images): reconcile the image inventory with filesystem changes

gns3server/db_migrations/versions/d9e8a2b7c401_image_inventory_reconciliation.py

@@ -0,0 +1,50 @@
+"""Track image availability and persistent synchronization jobs.
+
+Revision ID: d9e8a2b7c401
+Revises: c7e4a9f1d2b6
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = "d9e8a2b7c401"
+down_revision = "c7e4a9f1d2b6"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # Startup also uses this for unversioned databases previously created from
+    # metadata, which may already contain some/all of these additive fields.
+    inspector = sa.inspect(op.get_bind())
+    existing = {column["name"] for column in inspector.get_columns("images")}
+    for column in (
+        sa.Column("availability", sa.String(), nullable=False, server_default="unknown"),
+        sa.Column("file_fingerprint", sa.String()),
+        sa.Column("last_seen_at", sa.DateTime()),
+        sa.Column("last_verified_at", sa.DateTime()),
+        sa.Column("last_error", sa.String()),
+    ):
+        if column.name not in existing:
+            op.add_column("images", column)
+    if inspector.has_table("image_sync_jobs"):
+        return
+    op.create_table(
+        "image_sync_jobs",
+        sa.Column("job_id", sa.String(), primary_key=True),
+        sa.Column("status", sa.String(), nullable=False),
+        sa.Column("dry_run", sa.Boolean(), nullable=False),
+        sa.Column("force_checksum", sa.Boolean(), nullable=False),
+        sa.Column("finished_at", sa.DateTime()),
+        sa.Column("counts", sa.JSON(), nullable=False),
+        sa.Column("errors", sa.JSON(), nullable=False),
+        sa.Column("created_at", sa.DateTime(), server_default=sa.func.current_timestamp()),
+        sa.Column("updated_at", sa.DateTime(), server_default=sa.func.current_timestamp()),
+    )
+
+
+def downgrade():
+    op.drop_table("image_sync_jobs")
+    # Do not rebuild images: dropping the old table during a SQLite batch
+    # rebuild would cascade-delete image_template_map entries with FK enabled.
+    for name in ("last_error", "last_verified_at", "last_seen_at", "file_fingerprint", "availability"):
+        op.drop_column("images", name)