magento2 stock movement module Requires Magento 2.2+ due to following bug magento/magento2#4857
observing following events
<event name="cataloginventory_stock_item_save_after">
<event name="checkout_submit_all_after">
<event name="cataloginventory_stock_revert_products_sale"> //todo
<event name="sales_order_item_cancel"> //todo
the module will store in a separate table information about product (id,sku), current value, variance and which event triggered it (order, admin change, api //todo) An admin grid is shown under Catalog menu
performance and improvents: actually it seems magento doesn't provide an unique event for the stock movement so we have to observer different events.
The event cataloginventory_stock_item_save_after is triggered only in the admin area. I believe the module would be simpler and faster if 1 single event could be observed.