sequence-firestore-facade.txt

@startuml

title "Firestore Facade in Apigee X/hybrid"

actor User as u
entity "Client App" as b
entity "Cloud\nFirestore database" as gfd
box "Apigee API Platform" #LightBlue
entity "API Proxy\nfirestore-data-proxy-v1" as fdp
entity "SharedFlow\nsf-firestore-facade-lookup-v1" as ffl
entity "SharedFlow\nsf-firestore-facade-populate-v1" as ffp
end box
participant "Backend" as backend

u -> b: User interaction
b -> b: App activity
b -> fdp: Access the firestore facade api

note over gfd,ffp: "Apigee API proxy and shared flows acting as a facade in front of Cloud Firestore db" 

fdp -> ffl: Lookup data from the Cloud Firestore db based on base path, path suffix and encoding type (base64 only)
ffl -> ffl: calculate the document key (cache key)\ncacheKey = encodingType( basePath + pathSuffix)
ffl -> gfd: Lookup shared flow acting as a facade with Cloud Firestore, using the cache key\ncall is executed using an ID token
gfd -> gfd: lookup in the Cloud Firestore db using cache key

opt Data retrieved from Cloud Firestore
    gfd -> ffl: data is retrieved from Cloud Firestore (lookup status)
    ffl -> ffl: set context variables:\nflow.lookup.hit = true \nflow.lookup.content = "<json content retrieved from cache>" \nflow.lookup.status.code = 200
    ffl -> fdp: shared flow response
end

opt Data is NOT retrieved from Cloud Firestore
    gfd -> ffl: data is not retrieved from Cloud Firestore (lookp status)
    ffl -> ffl: set context variables:\nflow.lookup.hit = false \nflow.lookup.content = "none" \nflow.lookup.status.code > 399
    ffl -> fdp: shared flow response
    fdp -> backend: request is forwarded to the backend API
    backend -> fdp: backend response
    fdp -> ffp: Populate data from the Cloud Firestore db based on base path, path suffix and encoding type (base64 only)
    ffp -> ffp: calculate the cache key\ncacheKey = encodingType( basePath + pathSuffix)
    ffp -> gfd: Populate shared flow acting as a facade with Cloud Firestore, using the cache key\ncall is executed using an ID token
    gfd -> gfd: populate backend response in the Firestore db using cache key
    gfd -> ffp: firestore populate status
    ffp -> ffp: set context variables:\nflow.populate.content = true \nflow.populate.status.code = 200 \nflow.populate.cachekey = <cacheKey> \nflow.populate.extcache.documentid = <firestore documentId> \nflow.populate.extcache.collectionid = <firestore collectionId>
    ffp -> fdp: shared flow response
    
end

fdp -> b: JSON response is sent back to the app (200 OK)

@enduml