feat: The migration script reads from slaves mongo instance (#232)

migration/infrastructure/mongo_database.py

@@ -6,30 +6,30 @@
 
 from migration.domain.connection import Connection
 from tapiriik.database import db
-
+from pymongo import ReadPreference
 
 def get_all_connections() -> List[Connection]:
-    return [Connection.to_connection(conn) for conn in db.connections.find()]
+    return [Connection.to_connection(conn) for conn in db.connections.with_options(read_preference=ReadPreference.SECONDARY).find()]
 
 
 def get_connections_by_partner_name(partner_name: str) -> List[Connection]:
-    return [Connection.to_connection(conn) for conn in db.connections.find({"Service": partner_name})]
+    return [Connection.to_connection(conn) for conn in db.connections.with_options(read_preference=ReadPreference.SECONDARY).find({"Service": partner_name})]
 
 
 def get_connection_by_id(connection_id: ObjectId) -> Connection | None:
-    connection_dict = db.connections.find_one({"_id": connection_id})
+    connection_dict = db.connections.with_options(read_preference=ReadPreference.SECONDARY).find_one({"_id": connection_id})
     if connection_dict is not None:
         return Connection.to_connection(connection_dict)
     else:
         return None
 
 
 def get_all_users() -> list:
-    return list(db.users.find())
+    return list(db.users.with_options(read_preference=ReadPreference.SECONDARY).find())
 
 
 def get_user_by_connection_id(connection_id: ObjectId) -> List[dict]:
-    return list(db.users.aggregate(
+    return list(db.users.with_options(read_preference=ReadPreference.SECONDARY).aggregate(
         [
             {
                 '$match': {
@@ -45,7 +45,7 @@ def get_user_by_connection_id(connection_id: ObjectId) -> List[dict]:
 
 
 def get_user_connected_to_decathlon() -> List[dict]:
-    return list(db.users.aggregate(
+    return list(db.users.with_options(read_preference=ReadPreference.SECONDARY).aggregate(
         [
             {
                 '$match': {