Everything I found on the internet about Spring Cloud Netflix is about running microservices from Boot applications using #EnableEurekaClients and so on.
Now I'm trying to connect my logging microservice within a traditional war application (springmvc, jaxws etc) - piece of legacy which can not be converted to Boot or modified in any way (by technical task).
I've created a new maven module "log-server-client" that knows nothing about upper web layer and intended to be used as a simple dependency in any maven project.
How should I configure access to Spring Cloud Netflix for this simple dependency? At least, how to configure Eureka and Ribbon?
I just extracted some lines of code from RestTemplate and created my custom JmsTemplate (microservice works with jms remoting with apache camel and activemq), exactly how it is done in RestTemplate, but this code stil lacks connection to infrastructure
afaik, we can create a global singleton bean, run a separate thread from this bean, and run Boot app from this thread, but don't you think that it is very ugly and can lead to problems? How it really should be used?
Great question!
One approach is to use a "sidecar". This seems to be a companion Spring Boot application that registers with the Eureka Server on behalf of your traditional web app.
See e.g.:
http://www.java-allandsundry.com/2015/09/spring-cloud-sidecar.html
http://cloud.spring.io/spring-cloud-netflix/spring-cloud-netflix.html#_polyglot_support_with_sidecar
Another approach is to use the following library:
"A small lib to allow registration of legacy applications in Eureka service discovery."
https://github.com/sawano/eureka-legacy-registrar
This library can be used outside of Spring Boot.
Related
I have been working for a while with Spring micro-services and have no come across Apache Camel as a tool for building micro-services. I'm unclear -- is Apache Camel a replacement for creating micro-sevices with Spring Boot or does it add functionality / short-cuts to developing such services with Spring Boot? It's already fairly simple to create microservices with Spring Boot so it's hard to imagine what Apache Camel would add but that is the essence of my question.
Apache Camel has nothing to do with microservices.
It's an implementation of the Enterprise Integration Patterns: https://www.enterpriseintegrationpatterns.com/
Apache Camel provides an implementation for most of the patterns from the book from Gregor Hohpe and Bobby Woolf. Plus a variety of inbound and outbound endpoints to integrate with systems like the file system, FTP, HTTP, Messaging, Facebook etc.
Find more information on the website: https://camel.apache.org/
There is a Spring Boot Starter project to run Camel in a Spring Boot application:
https://camel.apache.org/spring-boot.html
what Apache Camel would add, that is the essence of my question
In service of declaring REST based microservices, Camel's REST DSL provides a fluent API for declaring microservices. Take for example:
rest("/books").produces("application/json")
.get().outType(Book[].class)
.to("bean:bookService?method=getBooks(${header.bookCategory})")
Should tell you at a glance that requests to the path /books will get you a List of Book, as long as you send a request parameter named bookCategory. This is mapped to a POJO bean called bookService.
Spring Boot is a framework which simplifies application packing and startup while Spring is the actual framework which has libraries for performing various tasks.
Technically, we can use Camel for building micro-services as well and many aspects of camel depend on Spring. If you foresee many integration related functionality like sending email or communicating with other system, you can use also use Hexagonal architecture.
I know that Spring Boot, in contrast to Spring Framework, does not support WAR deployment for Spring WebFlux applications. My question is simple: will it ever in the future?
My use case is this: we have a lot of customers that still live in the traditional "we deploy everything on application server X" world. So although we would like to push standalone JARs, they are not ready (yet). We heavily use Spring Boot, and would really like to continue to do so, so abandoning that is not an option.
We are building reactive applications and would like to use Spring WebFlux for that, but we still need to deploy to application servers, so that is not an option. In the meantime we avoid Spring WebFlux and simply use Controllers, which works, but is not as elegant. Hence my question.
There are no plans to support Spring WebFlux with war deployments. However, you can use reactive return types, Reactor's Mono and Flux and those from RxJava, with Spring MVC packaged and deployed as war. That will allow you to build an entire reactive pipeline as you would with WebFlux, but deployed to an application server. It doesn't give you all of the benefits of full-blown reactive (no event loop-based concurrency, for example), but it can be a good middle ground for those in your situation.
I have just built a RESTful web service with Spring Boot.
I now want to utilise the RESTful web service and start making calls to it by building a java console application (eventually adding GUI and security).
I was wondering if I can use any of the Spring functionality outside of the Spring (Boot) environment and use it in my java console application? For example, can I use Spring's RestTemplate in my non-Spring java application to make the REST api calls? I am new to Spring and I want to stick as close to Spring as possible. I think you can't, but I just want to make sure.
If not possible, I know you can create non-web application with Spring. Is it possible to integrate a GUI? Might not be best practice, just exploring what is possible and conventional.
Spring Boot is not coupled, in any way, to an application type. You can run command-line only apps, batch apps, web apps or any other kind of apps with it. You can even benefit from Spring Boot's auto-configuration.
In the case of the RestTemplate you may want to import spring-web directly rather than spring-boot-starter-web. Or you could add the starter and exclude the embedded container (spring-boot-starter-tomcat). Spring Boot will auto-adapt and not start an embedded web server in that case.
we are evaluating Eureka as central SD environment for our Spring Boot applications. Here we are using Spring Cloud. We figured out, that due to the fact, that we make use of RestEasy quite a lot and Eureka is based on Jersey, we run into bigger conflicts. Our rest-easy based APIs are throwing a lot of errors. It's basically no good idea to mix Jersey with Resteasy in the same application.
Question: Is there a way to change the jersey dependency or remove the lib somehow in order to avoid lib problems with RestEasy?
Best
fri
Not currently, it's how the eureka client is built. An alternative might be spring-cloud-consul, which doesn't use eureka, but provides integration with Ribbon and Zuul. Hystrix also works fine.
I've developed a spring integration component that is to sit on a server and process messages coming in over an inbound RMI channel do some processing/filtering and then send out some messages over a different RMI channel.
Currently, for testing, I've been running it using a Main class that just loads the context, which sets up the inbound RMI gateway and it's working fine. But I don't think that this is appropriate for a production environment.
What is the best way to deploy this type of project to a server?
If I were working in a .Net I'd be deploying this type of application as a windows service, is that what I should be doing here?
The application that is sending me data is hosted in Tomcat, would it be a good idea to also run this application within the same Tomcat container (Current requirements are for both components to be on the same machine this may change)? And if so how?
I'm currently looking into Spring Boot, am I on the right path?
I think the best would be Spring Boot, as it's made to easily allow running different types of applications. Also, you don't need Tomcat if you can run the same component with a simple Main and not using UI. Spring Boot, also, has a sample using Spring Integration here, so you should be up and running in no time.