001-migration-ui-redesign (#3)

Reviewed-on: #3

backend/src/core/migration_engine.py

@@ -0,0 +1,81 @@
+# [DEF:backend.src.core.migration_engine:Module]
+#
+# @SEMANTICS: migration, engine, zip, yaml, transformation
+# @PURPOSE:   Handles the interception and transformation of Superset asset ZIP archives.
+# @LAYER:     Core
+# @RELATION:  DEPENDS_ON -> PyYAML
+#
+# @INVARIANT: ZIP structure must be preserved after transformation.
+
+# [SECTION: IMPORTS]
+import zipfile
+import yaml
+import os
+import shutil
+import tempfile
+from pathlib import Path
+from typing import Dict
+# [/SECTION]
+
+# [DEF:MigrationEngine:Class]
+# @PURPOSE: Engine for transforming Superset export ZIPs.
+class MigrationEngine:
+    
+    # [DEF:MigrationEngine.transform_zip:Function]
+    # @PURPOSE: Extracts ZIP, replaces database UUIDs in YAMLs, and re-packages.
+    # @PARAM:   zip_path (str) - Path to the source ZIP file.
+    # @PARAM:   output_path (str) - Path where the transformed ZIP will be saved.
+    # @PARAM:   db_mapping (Dict[str, str]) - Mapping of source UUID to target UUID.
+    # @RETURN:  bool - True if successful.
+    def transform_zip(self, zip_path: str, output_path: str, db_mapping: Dict[str, str]) -> bool:
+        """
+        Transform a Superset export ZIP by replacing database UUIDs.
+        """
+        with tempfile.TemporaryDirectory() as temp_dir_str:
+            temp_dir = Path(temp_dir_str)
+
+            try:
+                # 1. Extract
+                with zipfile.ZipFile(zip_path, 'r') as zf:
+                    zf.extractall(temp_dir)
+
+                # 2. Transform YAMLs
+                # Datasets are usually in datasets/*.yaml
+                dataset_files = list(temp_dir.glob("**/datasets/*.yaml"))
+                for ds_file in dataset_files:
+                    self._transform_yaml(ds_file, db_mapping)
+
+                # 3. Re-package
+                with zipfile.ZipFile(output_path, 'w', zipfile.ZIP_DEFLATED) as zf:
+                    for root, dirs, files in os.walk(temp_dir):
+                        for file in files:
+                            file_path = Path(root) / file
+                            arcname = file_path.relative_to(temp_dir)
+                            zf.write(file_path, arcname)
+                
+                return True
+            except Exception as e:
+                print(f"Error transforming ZIP: {e}")
+                return False
+
+    # [DEF:MigrationEngine._transform_yaml:Function]
+    # @PURPOSE: Replaces database_uuid in a single YAML file.
+    def _transform_yaml(self, file_path: Path, db_mapping: Dict[str, str]):
+        with open(file_path, 'r') as f:
+            data = yaml.safe_load(f)
+
+        if not data:
+            return
+
+        # Superset dataset YAML structure:
+        # database_uuid: ...
+        source_uuid = data.get('database_uuid')
+        if source_uuid in db_mapping:
+            data['database_uuid'] = db_mapping[source_uuid]
+            with open(file_path, 'w') as f:
+                yaml.dump(data, f)
+    # [/DEF:MigrationEngine._transform_yaml]
+
+# [/DEF:MigrationEngine]
+
+# [/DEF:backend.src.core.migration_engine]