I have:
multiple ApplicationRunners
and multiple #Scheduled jobs that run immediately after the app starts, and periodically after that.
I want to write a message to the log when the app is ready to handle HTTP requests; so that I verify all necessary jobs have been executed before the app can accept HTTP requests.
Q1: How/Where to write this log message?
Q2: How to run code before accepting HTTP requests?
Note: my app extends SpringBootServletInitializer
As answered by #m-deinum, The app won't accept HTTP traffic until all ApplicationRunner beans have finished running.
I have verified this.
I am closing this question.
Related
My application is simple 3-tier Spring Boot rest web-service with usual synchronous endpoints.
But since the period of getting response from downstream system where my service sends requests is quite long (kind of 60 seconds), I need to add support of asynchronous REST calls to my service to save upstream systems from a response awaiting. In other words, if a response to a downstream system is going to take more than 60 seconds (timeout), then the upstream system break the connection with my service and keeps its doing...
But when the response come, my service using "reply-to" header from the upstream system will send the response to the upstream system.
All the things above are kind of call back or webhook.
But I didn't find any examples of implementation.
How to implement this mechanism?
How can I find more information?
Does Spring Boot have something to implement it out-of-box?
Thank you for attention!
You can use the #Async annotation from Spring. You will also need to enable in your application this by setting #EnableAsync.
An important note is that your method with the #Async annotation should be on a different class from where it is being called. This will let the Spring proxy intercept the call and effectively do it asynchronous.
Please find here the official tutorial.
I have an spring boot application that pulls message from an cloud message queue and put it back to a cloud db. I realize that my program is single thread(I am not using request mapping, just pull,process,put to db). I want Spring handle concurrency things. So can I make a dispatcher function, which calls controller in the application with #RequestMapping?
#RestController
#RequestMapping("/test")
public class GatewayController {
#RequestMapping("/service")
public void InvokeService(...) {...}
}
I need mutithread to call other service for response, which I don't want it to block others. If I recieve 10 messages, I want it to call /test/service... which have 10 threads processing them.
My question is:
Will Spring make the controller multithread?
How to call its own controller? Send request to the url? (I don't need response from controller, just let controller call a service to put response in a db on could)
RequestMapping is MVC thing - intended to issue http requests. And yes, it uses tomcat under the hood.
If you'll inject RestController into your class it won't issue any HTTP requests, you'll only call the controller as a regular bean. If you consume messages in one thread, it won't become multithreaded to answer your first question.
You can, of course, create HTTP request but frankly it's just wrong. So don't do it. This answers your second question to some extent :)
Now, there is nothing wrong conceptually if your microservice acts as a consumer and producer and deals with queues, not all microservices have to be accessible via HTTP.
In order to work in a multi threaded environment:
Check whether you can consume messages in a multi-threaded manner. Maybe the client of your "cloud message queue" offers multi-threaded configuration (thread pool or something).
If it's not possible, create a thread pool executor by yourself and upon each message submit the processing task to this thread pool. This will make the processing logic multithreaded with a parallelism level confined by the thread pool size and thread pool configurations.
I am developing a Spring boot application. From my application we are calling an external RestService and want to retry if RestCall fails for any reason.
I know that #Retryable within spring should take care of this. I am trying to implement something like below with parameters:
#Retryable(maxAttempts=3,value=RunTimeException.class,backoff = #Backoff(delay = 900000))
Now my problem is, there are multiple clients who will call this service. When client1 is calling this service, i want to retry when a failure occurs after 15min. When client2 is calling this service, i want to retry when a failure occurs after 1sec.
So i want to know if there is any way we can configure the delay in retryable based on client1 or client2.
Any suggestions are helpful.
You can use a ThreadLocal<Long> #Bean to store the delay and then use delayExpression="#threadLocalBean.get().
However, suspending a thread for 15 minutes is a bit severe.
You would be better using a scheduler for the retries in that case.
I am working on a on Spring web service which calls a thread for a long running task, as I don't want to keep the user busy because the task can be really long.
I want to notify the user through web socket when the task on the thread has completed. What is the best procedure to do so in spring??
Spring websocket can be used for this purpose.
I beleive this would help you initially at least. https://spring.io/guides/gs/messaging-stomp-websocket/
I am new to spring and so not sure if what I intend to do is possible.
I need to create an asynchronous webservice and a worker server (broker), both using the model & controller aspects of spring.
The webservice needs to send it's client's requests on to the broker via JMS and then instantly send a response back to the client indicating the request has been queued.
The broker is intended to remain live, processing messages from multiple webservice instances and sending back the results via an output JMS queue. The reason the broker needs to remain live is because the work to process each webservice message involves calling other webservices, some of which may be asynchronous and which may take a lot of time to process.
Additionally I do not want to spawn multiple instances of the broker as it is designed to handle multiple concurrent messages.
Is it possible to create both the webservice and broker within the same spring project, with both running in a web container such as tomcat or do I need to code them in separate projects, with perhaps the broker as a traditional standalone server rather than a web container servlet?
If so could someone point me in the right direction to creating a stay-alive broker within spring/tomcat.
I understand the webservice and JMS side of things, so do not need any help with that.