bug(medcat-trainer): CU-869ctq789 Fix saving model packs

medcat-trainer/webapp/api/api/views.py

@@ -1,8 +1,9 @@
 import logging
 import os
 from smtplib import SMTPException
-from tempfile import NamedTemporaryFile
+from tempfile import NamedTemporaryFile, TemporaryDirectory
 from typing import Any
+import shutil
 
 from background_task.models import Task, CompletedTask
 from django.contrib.auth.views import PasswordResetView
@@ -579,11 +580,42 @@ def save_models(request):
     project = ProjectAnnotateEntities.objects.get(id=p_id)
     cat = get_medcat(project=project)
 
-    cat.cdb.save(project.concept_db.cdb_file.path)
+    if project.concept_db is not None:
+        # CDB / vocab based
+        cat.cdb.save(project.concept_db.cdb_file.path, overwrite=True)
+    else:
+        # ModelPack based project
+        _overwrite_model_pack(cat, project.model_pack.path)
 
     return Response({'message': 'Models saved'})
 
 
+def _overwrite_model_pack(cat, model_path: str):
+    # NOTE: cannot overwrite, so working around
+    #       currently CAT.save_model_pack does not provide a method to
+    #       allow overwriting an existing model pack
+    with TemporaryDirectory() as tmp_dir:
+        # making new folder name so that it's copied
+        # to the specific path rather than into the folder
+        temp_folder = os.path.join(tmp_dir, "model_copy")
+        shutil.move(model_path, temp_folder)
+        try:
+            cat.save_model_pack(
+                os.path.dirname(model_path),
+                pack_name=os.path.basename(model_path),
+                add_hash_to_pack_name=False)
+        except Exception as e:
+            logger.warning("Unable to save model pack. Restoring previous state. Issue while saving model:", exc_info=e)
+            if os.path.exists(model_path):
+                shutil.rmtree(model_path)  # remove partial/corrupt output
+            # restore original
+            try:
+                shutil.move(temp_folder, model_path)
+            except Exception as restore_err:
+                logger.error("Failed to restore model pack:", exc_info=restore_err)
+            raise
+
+
 @api_view(http_method_names=['POST'])
 def get_create_entity(request):
     label = request.data['label']