Lot of migration work (better normalization), and more visibility work

utils/migrations.py

@@ -0,0 +1,56 @@
+"""Automatic migration tools for the da:ta stored in MongoDB."""
+import logging
+from abc import ABC
+from abc import abstractmethod
+from typing import List
+from typing import Type
+
+from config import DB
+
+logger = logging.getLogger(__name__)
+
+# Used to keep track of all the defined migrations
+_MIGRATIONS: List[Type["Migration"]] = []
+
+
+def perform() -> None:
+    """Perform all the defined migration."""
+    for migration in _MIGRATIONS:
+        migration().perform()
+
+
+class Migration(ABC):
+    """Abstract class for migrations."""
+
+    def __init__(self) -> None:
+        self.name = self.__class__.__qualname__
+        self._col = DB.migrations
+
+    def __init_subclass__(cls, **kwargs):
+        super().__init_subclass__(**kwargs)
+        _MIGRATIONS.append(cls)
+
+    def _apply(self) -> None:
+        self._col.insert_one({"name": self.name})
+
+    def _reset(self) -> None:
+        self._col.delete_one({"name": self.name})
+
+    def _is_applied(self) -> bool:
+        return bool(self._col.find_one({"name": self.name}))
+
+    @abstractmethod
+    def migrate(self) -> None:
+        """Expected to be implemented by actual migrations."""
+        pass
+
+    def perform(self) -> None:
+        if self._is_applied():
+            logger.info(f"Skipping migration {self.name} (already applied)")
+            return
+
+        logger.info(f"Performing migration {self.name}...")
+        self.migrate()
+
+        self._apply()
+        logger.info("Done")