Initialize clean CSR inventory repository

scripts/export_sqlite.py

@@ -0,0 +1,57 @@
+"""Export a consistent SQLite snapshot without modifying the source database."""
+import argparse
+import os
+from pathlib import Path
+import sqlite3
+import sys
+import tempfile
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("source", type=Path)
+    parser.add_argument("output", type=Path)
+    args = parser.parse_args()
+    source = args.source.resolve(strict=True)
+    output = args.output.resolve()
+    if output.exists():
+        parser.error("Output already exists; choose a new filename.")
+    output.parent.mkdir(parents=True, exist_ok=True)
+    # Refuse to overwrite either the original database or an earlier export.
+    with tempfile.TemporaryDirectory(prefix="csr-sqlite-export-") as temporary:
+        snapshot = Path(temporary) / "snapshot.sqlite3"
+        origin = sqlite3.connect(source.as_uri() + "?mode=ro", uri=True)
+        destination = sqlite3.connect(snapshot)
+        try:
+            origin.backup(destination)
+        finally:
+            destination.close()
+            origin.close()
+        os.environ["SQLITE_MIGRATION_SNAPSHOT"] = str(snapshot)
+        os.environ["DJANGO_SETTINGS_MODULE"] = "csr_inventory.sqlite_migration_settings"
+        sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+        import django
+        django.setup()
+        from django.core.management import call_command
+        from django.db import connections
+        try:
+            call_command("migrate", interactive=False, verbosity=0)
+            with output.open("x", encoding="utf-8") as stream:
+                os.chmod(output, 0o600)
+                try:
+                    call_command(
+                        "dumpdata", natural_foreign=True,
+                        exclude=["contenttypes", "auth.permission", "sessions.session"],
+                        stdout=stream, verbosity=0,
+                    )
+                except BaseException:
+                    stream.close()
+                    output.unlink()
+                    raise
+        finally:
+            connections.close_all()
+    print(f"Export created: {output}. Original SQLite database unchanged.")
+
+
+if __name__ == "__main__":
+    main()