Queue | 本人的RabbitMQ和Kafka详细笔记以及示例代码 | Pub Sub library

How to manage access to shared resources using Project Reactor?

Given an imaginary critical component that can execute only operation at the time (file store, expensive remote service, etc), how could one orchestrate in reactive manner access to this component if there are multiple points of access to this component (multiple API methods, subscribers...)? If the resource is free to execute the operation it should execute it right away, if some other operation is already in progress, add my operation to the queue and complete my Mono once my operation is completed.

My idea is to add tasks to the flux queue which executes tasks one by one and return a Mono which will be complete once the task in the queue is completed, without blocking.

I am running a Spring Boot app that uses WebClient for both non-blocking and blocking HTTP requests. After the app has run for some time, all outgoing HTTP requests seem to get stuck.

WebClient is used to send requests to multiple hosts, but as an example, here is how it is initialized and used to send requests to Telegram:

WebClientConfig:

I am new to queue & threads kindly help with the below code , here I am trying to execute the function hd , I need to run the function multiple times but only after a single run has been completed

Ok, I'm totally lost on deadlock issue. I just don't know how to solve this.

I have these three tables (I have removed not important columns):

When the click event is fired from the mouse, it behaves as expected:

First the listener 1 is pushed into the stack where it queues promise 1 in Microtask Queue(or Job Queue). When listener 1 is popped off, the stack becomes empty. And the promise 1 callback is executed before the listener 2(which is waiting in the Task Queue(or Callback Queue). After promise 1 callback is popped off, the listener 2 is pushed into the stack. So the output is :

Listener 1 Microtask 1 Listener 2 Microtask 2

However when the click is triggered via JavaScript code, it behaves differently:

The callback is pushed into the stack even before the click() function is completed (i.e. call stack is not empty). The output here is :

Listener 1 Listener 2 Microtask 1 Microtask 2

Here's the code:

I am using the Google Tag Manager with a single tag referencing a default Google Analytics script. My solution is based on the information from these resources:

• https://www.iubenda.com/en/help/27137-google-consent-mode
• https://www.simoahava.com/analytics/consent-settings-google-tag-manager/
• https://www.simoahava.com/analytics/consent-mode-google-tags/

The code is simple (commit):

index.html: define gtag() and set denied as a default for all storages

React collects operations(like DOM operations such 'ADD','REPLACE','REMOVE' and more) so they could execute them in batch in one shot at the end of each render.

for example, setState call inside React component is scheduled to the end of the construction of this React tree by adding this operation to the operation queue. then react will go over this queue and will decide what changes need to be made to the DOM.

React will decide whether or not to call another render based on whether or not the operation queue is empty or not.

more info on this awesome tutorial which summarizes the basics of how React works internally.

I need access to this queue to decide whether or not the current render was the last for a very custom React component. (YES maybe I can avoid it but currently, this is my requirement)
the access must be from inside of this component.

my check will be called from the lastest useEffect which is after the render ends and the DOM was updated and is the latest lifecycle event, so if the operation queue is empty there will be no more renders for sure. (here nice article explains and demonstrates the order of hook calls)

couldn't find any public API, but a workaround would also be acceptable. (forking and editing React is not a workaround)

this src file is probably the main logic to this queue. and this is the type of the actual queue. however this is the source code and this queue is not exported in the built versions of react(neither development or production build)

so, is there a way to access the internal operation queue of React?

I have a django app running in production. Its database has main write instance and a few read replicas. I use DATABASE_ROUTERS to route between the write instance and the read replicas based on whether I need to read or write.

I encountered a situation where I have to do some async processing on an object due to a user request. The order of actions is:

1. User submits a request via HTTPS/REST.
2. The view creates an Object and saves it to the DB.
3. Trigger a celery job to process the object outside of the request-response cycle and passing the object ID to it.
4. Sending an OK response to the request.

Now, the celery job may kick in in 10 ms or 10 minutes depending on the queue. When it finally tuns, the celery job first tries to load the object based on the ID provided. Initially I had issues doing a my_obj = MyModel.objects.get(pk=given_id) because the read replica would be used at this point, if the queue is empty and the celery job runs immediately after being triggered, the object may have not propagated to the read-replicas yet.

I resolved that issue by replacing my_obj = MyModel.objects.get(pk=given_id) with my_obj = MyModel.objects.using('default').get(pk=given_id) -- this ensures the object is read from my write-db-instance and is always available.

however, now I have another issue I did not anticipate.

calling my_obj.certain_many_to_many_objects.all() triggers another call to the database as the ORM is lazy. That call IS being done on the read-replica. I was hoping it would stick to the database I defined with using but that's not the case. Is there a way to force all sub-element objects to use the same write-db-instance?