Draft notes to be formed into a white paper
Define the problem:
Course-grained access to fine-grained resources (“chattiness”)
Network latency
Getting rid of composites
Alternate security protocols
Solution: create a specialized backend API, which sits “close” to the Ed-Fi API (for low network latency).
Central Aggregating Gateway: more generic design than a BFF, can support multiple user interfaces
“A central-purpose aggregating gateway sits between external user interfaces and downstream microservices and performs call filtering and aggregation for all user interfaces. Without aggregation, a user interface may have to make multiple calls to fetch required information, often throwing away data that was retrieved but not needed.”
BFF: designed for a single front-end
“The main distinction between a BFF and a central aggregating gateway is that a BFF is single purpose in nature—it is developed for a specific user interface.”
https://learning.oreilly.com/library/view/building-microservices-2nd/9781492034018/ch14.html by Sam Newman, ch 14, O’Reilly Media, Inc.
Solves the impedance mismatch between systems.
Similar to the Facade pattern in OO systems
Alternatives
GraphQL - why not? Well-defined need is easier to express and reason about. Create a simple single definition of an API.
Design
BEF app needs a key and secret to an ODS/API. Maybe to many of them.
Analyze your authorization strategy and needs.
Cache local data for higher performance.
Possible implication: ETL
Change Queries (ETL!)
Show basic interaction
Definitely(?) implies caching.
Storing multiple tenants' data? Decide on a multi-tenancy pattern for segregating the data in the caching layer.
Evolutionary diagrams:
FE to BFF to BEF to ODS/API
Add caching layer and ETL
Resiliency patterns and more