circuit-breaker | Port of Akka 's CircuitBreaker pattern to Node.js

I coded a resilience strategy based on retry, and a circuit-breaker policies. Now working, but with a issue in its behavior.

I noticed when the circuit-breaker is on half-open, and the onBreak() event is being executed again to close the circuit, one additional retry is triggered for the retry policy (this one aside of the health verification for the half-open status).

Let me explain step by step:

I've defined two strongly-typed policies for retry, and circuit-breaker:

Conditionally I want to switch the circuit breaker switch off/on by setting spring.cloud.circuitbreaker.resilience4j.enabled=false. My logic should stay intact from circuit-breaker logic.

I tried using the below demo example to extend to my requirements, I am trying to bind circuit breaker call on target method based on circuit breaker flag spring.cloud.circuitbreaker.resilience4j.enabled=true in application.property, true and false case. There could be a simpler way to achieve this, help me if any other solution than what I tried.

Example: spring cloud circuit-breaker-resiliency4j example

Tried calling happy path - Work fine when there is no exception [response comes within 3 seconds as time limiter set to 3seconds in bean creation]

application.properties:

There is a ActiveMQ queue (QueueA). A service (MyService) subscribes to messages, processes it and sends the message to another ActiveMQ queue (QueueB).

I am currently using Vertx CircuitBreaker to attempt retry on requesting event bus. Based on the ReplyException.ReplyFailure I want to skip or avoid retries.

For example I don't want retry when the event bus responds with ReplyFailure.RECIPIENT_FAILURE, because this kind of error are not application error instead logic validation failure.

Below is my code,

In order to achieve High Availability we have created two blob containers under different storage accounts at different Azure regions.

So that, if application find issues while WRITING to primary blob container, application will perform circuit-breaker logic and if issue persists even after threshold number of attempts, application will start WRITING to stand-by blob storage account which is located in different Azure location & this architecture works fine.

Code used to switch from primary to secondary:

I'm trying to figure out what is the best wait to implement a circuit breaker based of the number of requests been served in a Typescript/express application instead of fails percentage.

Since the application is meant to be executed by large number of users and under a heavy load, I'm trying to customize the response code in order to trigger a horizontal scaling event with k8s/istio.

The first thing I want to start with is to get is the number of requests in nodejs eventloop event if there is some async work in progress, because a big part of my request are executed asynchronously using async/await.

BTW:
I have seen these Libs

• https://github.com/bennadel/Node-Circuit-Breaker
• https://github.com/nodeshift/opossum

Is there any good Idea/path I can start with in order to make this possible ?

I want to use Polly to implement a Circuit Breaker pattern.

In the docs, there is a description of the Half Open state, and there it says:

• If a handled exception is received, that exception is rethrown, and the circuit transitions immediately back to open, and remains open again for the configured timespan.
• If an unhandled exception is received, the circuit remains in half-open.

I'm not sure I understand the difference here between handled and unhandled exception. We are describing a case where an action is run by the policy and is throwing an exception.

When they say the exception is handled, where do they mean it's being handled? because as we said, the action threw it so doesn't it mean it's unhandled?

It makes me not understand completely when the half open state remains half open and when does it transition to open.

I get above error when I'm trying to create a persisting actor with SQL server persistence.

EDIT: what's weird when I clone repositories akka and akka persistence sql server and attach then instead using nuget packages is working as expected. I'm using followinf versions: "Akka" Version="1.4.11" "Akka.Persistence.SqlServer" Version="1.4.10"

I got alert stating elasticsearch has 2 unassigned shards. I made below api calls to gather more details.