Adding more protections for 502's during imports (#2220)

* Be more defensive on asset loading during imports
* On primary databases only import backups when we are actually able to make it to the target migration

CTFd/utils/exports/__init__.py

@@ -30,6 +30,7 @@ from CTFd.utils.exports.freeze import freeze_export
 from CTFd.utils.migrations import (
     create_database,
     drop_database,
+    get_available_revisions,
     get_current_revision,
     stamp_latest_revision,
 )
@@ -195,6 +196,15 @@ def import_ctf(backup, erase=True):
     mysql = get_app_config("SQLALCHEMY_DATABASE_URI").startswith("mysql")
     mariadb = is_database_mariadb()
 
+    # Only import if we can actually make it to the target migration
+    if sqlite is False and alembic_version not in get_available_revisions():
+        set_import_error(
+            "Exception: The target migration in this backup is not available in this version of CTFd."
+        )
+        raise Exception(
+            "The target migration in this backup is not available in this version of CTFd."
+        )
+
     if erase:
         set_import_status("erasing")
         # Clear out existing connections to release any locks

CTFd/utils/initialization/__init__.py

@@ -192,6 +192,11 @@ def init_request_processors(app):
 
     @app.before_request
     def needs_setup():
+        if import_in_progress():
+            if request.endpoint == "admin.import_ctf":
+                return
+            else:
+                return "Import currently in progress", 403
         if is_setup() is False:
             if request.endpoint in (
                 "views.setup",
@@ -213,7 +218,7 @@ def init_request_processors(app):
             if request.endpoint == "admin.import_ctf":
                 return
             else:
-                abort(403, description="Import currently in progress")
+                return "Import currently in progress", 403
 
         if authed():
             user_ips = get_current_user_recent_ips()

CTFd/utils/migrations/__init__.py

@@ -1,4 +1,6 @@
 import os
+import re
+from pathlib import Path
 
 from alembic.migration import MigrationContext
 from flask import current_app as app
@@ -48,3 +50,13 @@ def stamp_latest_revision():
     # Get proper migrations directory regardless of cwd
     directory = os.path.join(os.path.dirname(app.root_path), "migrations")
     stamp(directory=directory)
+
+
+def get_available_revisions():
+    revisions = []
+    directory = Path(os.path.dirname(app.root_path), "migrations", "versions")
+    for f in directory.glob("*.py"):
+        with f.open() as migration:
+            revision = re.search(r'revision = "(.*?)"', migration.read()).group(1)
+            revisions.append(revision)
+    return revisions