fanout | Kernel-based publish-subscribe system

I was recently hired as a junior dev as my first job for a bigger company which uses NetSuite. An old dev wrote a python script which handles pictures made by designers, that uploads pictures to NetSuite when they are uploaded to a specific folder.

Since the Script uses SHA1 I need to change the TBA to SHA256 because NetSuite does not support SHA1 anymore.

I have a hard time understanding the old dev's code, and find documentation on how to change the TBA from SHA1 to SHA256..

These are snippets from the code.

I am implementing ApiGateway-MicroService communication protocol in my app with MassTransit and RabbitMQ. That protocol is meant to replace "traditional" REST API communication between ApiGateway and Microservices (I am talking about simple request-response here and not about any kind of events, sagas, etc). So on microservice(s) side I have consumers (which respond to requests) and on ApiGateway side I have request clients. Usually microservice has let's say ~10 consumers (for example OrderingMicroservice has consumers for following requests: CreateOrder, UpdateOrder, GetOrderById, ListUserOrders etc). I am trying to figure out best topology (Masstransit + RabbitMQ) for this scenario.

Here are my goals, at least I think it should work like this:

A. Request messages (that are routed to consumer queue) should be durable for short time only (for example 20s) and then removed from the consumer queue (and request client should receive timeout error) and not routed to any other queue. So when microservice is temporary down or it is temporary too busy to receive next request from queue then request messages should be kept in the queue for 20s and then disappear.

B. Since RequestClient should timeout after ~20s, Response messages (that are routed to client "response-queue") should also be durable for short amount of time (~20s). Then they can disappear. If ApiGW is offline / too busy to receive response then response(s) should be discarded.

So basically I want to use MassTransit/RabbitMQ as a short-lived buffer between ApiGW and microservice(s).

I have two services, one acts as a consumer, the other as a producer. Following are my configurations for each of them.

Producer config

I have one queue-publisher and one hundred queue-subscribers. Subscribers bind to one queue. The Rabbit`s guide said that to each queue Rabbit creates single thread. I want to send all messages to subscribers through one queue and save all unsended messages in the same queue if destination subscriber is offline. I have two solutions:

1. I can send all messages through one queue to all subscribers by declaring exchange type "Direct" and bind to one QueueName. But if routingKey in publishing message not equals queue name, it doesnt save in queue, if direct consumer is offline.

suscriber`s code

I am implementing application in microservices architecture. I would like to attach some kind of event store to my solution. I am new to messaging with RabbitMQ, and probably i've configured something improperly. Let's simplify my solution, so imagine i have a simple common service which has to broadcast some messages to the bus. To register broker dependencies i use the following code:

I am struggling with typeScript syntax used in the snippet below. Can someone kindly clear it out for me.

I have a queue in RabbitMQ. I can't configurate this queue, I have to consume messages from it. Publisher don't use Masstransit for publishing. I am using Masstransit to consume messages from the queue.

When I am trying to configurate connection to the queue, I am receiving this error:

I have gone through the fundamentals of RabbitMQ. One thing I figured out that a publisher does not directly publish on a queue. The exchange decides on which queue the message should be published based on routing-key and type of exchange (code below is using default exchange). I have also found an example code of publisher.

I am new to AWS/Database. Since i am completely beginner to this, any suggestions will be appreciated.
Currently in the project it has been planned like data from AWS database will be pushed using SNS HTTP fanout to external MySql Database.
NOTE :
1.The data will be pushed by the Client using AWS SNS
2. We have no access to the AWS account nor we are planning to have a AWS account.
3. External MySql database is a private database running on Linux Server
I have gone through the Official documentation of AWS SNS, and also some websites. This is all i found :

1. Use external applications like Zapier to map the data.

2. Develop some application to map the data.

   Is it like using a Servlet application in the receiver side to update the table, or is there any other methods?
   

   AWS DB -----> SNS -----> _________ -----> External MySql DB

Thanks