Create delivery-data-to-sf

design-documents/storefront/delivery-data-to-sf

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+The goal of this document is to describe how to deliver data from the Magento Monolith to the StoreFront service.
+
+The desired state is to have Storage(s) on the SF side which should have all needed data to perform data for requested fields. (see https://github.com/magento/architecture/blob/master/design-documents/graph-ql/storefront-api.md)
+
+We will use Catalog SF as an example.
+
+1. How can data be added to the Storage?
+
+Storage (in the first iteration - just an MySQL table/mongodb db) will be fullfilled by Data Providers that can fetch information by "entity_id" and "scope_id"
+Data Providers will "live" on monolith side, so they can use Service Contracts to fetch the data
+
+2. Who is repsonsible for "fullfill" storage?
+Let's name it "Indexer" for now. Indexer is responsible to call Data Providers and put data to Storage.
+
+3. How can "Indexer" know that need to add data to Storage.
+
+There are 2 approaches to do it.
+3.1. Queue framework. 
+Add message to queue {"products_ids": [...], "scopes", "attributes": []} 
+
+Pors. 
+- Easier to decouple from monolith in future (in case we stop using Service Contracts in Data Providers)
+- Message already contains all needed information to call Data Proivider (entity_id/scopes)
+
+Cons.
+- Need to mannualy take care about adding message to the Queue
+-- create plugins/event listeners
+-- "parse" default scope to several scopes (E.g. Save product in "Default" scope)
+Cons. Quedstions
+-- How to handler events, that not passed from "product_model_save"? E.g. product import, catalog rule,...
+-- Price for composite product. How to update configuralbe price after simple price changed?
+
+
+3.2. MView mechanism
+We can create intermediate Magento Indexer and add listeners to all tables, that we want to take care
+
+Pors. 
+- Easier to implement
+
+Cons.
+- Message do not contains scopes. Need to call DataProviders with all scopes in system (just store?)
+- How to handler "create new store"
+
+
+4. Open questions
+How to display price? (configuration issue)
+ - we have configuiration "include tax"/"exclude tax"
+Init storage. 
+Do we need full reindex for specific cases?
+
+How Storage schema should looks like?
+E.g. For Catalog service. How can we handle staging ?
+... TBD
+
+![Storage filling diagram](https://github.com/magento-performance/architecture/blob/master/design-documents/storefront/storefront-api/fill-sf-storage.png?raw=true)