Posted on Jul 12

Azure Function App

Robust function characteristics

Avoid long-running functions
Plan cross-function communication
Write functions to be stateless
Write defensive functions
Security
Concurrency

Scaling

Event driven scaling
Concurrency in Function App Concurrency refers to the ability of a service to handle multiple requests or operations simultaneously. This can be achieved by
Parallelism Executing multiple tasks at the same time on different cpu/machine
Overlapping Execution Perform operation in a way that they dont block each other

Concurreny is achived by

-Thread pools
Assigning threads to handle incoming requests
-Async Operation
Async communication patterns to decouple tasks.
-Concurrency control mechanism

Pessimistic locking
Locking entire row to prevent users from modifying data that affects the current user
Optimistic Concurrency
Versioning
event driven architecture
Static Concurrency
Dynamic Concurrency

Fuction App Design Pattern

Database per Service - each service has its own private database
Shared database - services share a database
Saga - use sagas, which a sequences of local transactions, to maintain data consistency across services
Command-side replica - maintain a queryable replica of data in a service that implements a command
API Composition - implement queries by invoking the services that own the data and performing an in-memory join
CQRS - implement queries by maintaining one or more materialized views that can be efficiently queried
Domain event - publish an event whenever data changes
Event sourcing - persist aggregates as a sequence of events
Event based pattern In this way it can improve the speed, endurance and resilience of the process.
Async Pattern
With Async approachit eliminates blocking call

Consider async/await misuses anti patterns
Concurrency settings in host.json

"extensions": {
"http": {
"routePrefix": "api",
"maxOutstandingRequests": 200,
"maxConcurrentRequests": 100,
"dynamicThrottlesEnabled": true,
"hsts": {
"isEnabled": true,
"maxAge": "10"
},
"customHeaders": {
"X-Content-Type-Options": "nosniff"
}
}
}