Sharing of a view among microservies - spring

I'm splitting up a monolith web service into several microservices using spring boot. To reduce duplicated code I extracted shared parts in a maven module that is used in the different microservices.
The monolith application had a healthcheck page that showed various information about the state of the service and some debbuging infos. It is implemented with Spring MVC and jsp.
I'd like to use this view in each of the microservices. Whats the best way to do this without duplicating the view/controller?
I was thinking of adding a web module to the shared maven project that contains the controller, view, spring mvc settings,...
But I'm not sure if it is good to have two web modules in one microservice.

Have you considered using spring boot actuator to retrieve health (and more) application information?
http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#production-ready
You could then have another microservice that retrieves that information from each of your services, or just simply check it on then hitting the different endpoints (/health, /env, etc.).
UPDATE:
If you have you custom health logic you can even implement your own actuator endpoint for it. Furthermore, you can create your own library to reuse it in all your microservices:
http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#production-ready-customizing-endpoints-programmatically
46.4 Adding custom endpoints
If you add a #Bean of type Endpoint then it will automatically be exposed over JMX and HTTP (if there is an
server available). An HTTP endpoints can be customized further by
creating a bean of type MvcEndpoint. Your MvcEndpoint is not a
#Controller but it can use #RequestMapping (and #Managed*) to expose
resources.
[Tip]
If you are doing this as a library feature consider adding a
configuration class annotated with #ManagementContextConfiguration to
/META-INF/spring.factories under the key
org.springframework.boot.actuate.autoconfigure.ManagementContextConfiguration.
If you do that then the endpoint will move to a child context with all
the other MVC endpoints if your users ask for a separate management
port or address. A configuration declared this way can be a
WebConfigurerAdapter if it wants to add static resources (for
instance) to the management endpoints.

Related

How to prefix all controller paths but not management endpoints?

I have a Spring Boot application with a lot of controllers, and I want to run the service on a sub-path of an existing domain. So I've figured it would be nicer to have this configurable than to hardcode the path into all the request mappings.
I've considered all the approaches mentioned here https://www.baeldung.com/spring-boot-controllers-add-prefix, but they either also change the prefix of the actuator endpoints or are not globally enforced, so I'd prefer a different approach.
I want the actuator endpoints on /_system/ (changed by management.endpoints.web.base-path=/_system) and have only the /prefix as a load balancer target, so the management endpoints won't ever be reachable from the internet (in case I miss-configure the application and start leaking some sensitive info from the management endpoints).
I've also tried configuring management.server.base-path=/, but that seems to also be affected by the server.servlet.context-path and spring.mvc.servlet.path as the actuator seems to be registered "under" the main servlet dispatcher.
I was looking into registering a separate servlet dispatcher just for the actuator endpoints, but I've given up on researching it after some time because I feel like I'd have to override half of Spring Boot.
Any other ideas? Thanks

Custom Spring Actuator Endpoint which has subsystem and can be added dynamically

I'm looking for a way to implement custom endpoints for a reactive application using Spring Boot 2.2.
The endpoints have some subsystems and perform specific resource operations on the subsystems. The URL paths look like:
/actuator/system1/subsystem_a
/actuator/system1/subsystem_b
/actuator/system2/subsystem_c
Furthermore, system1 and system2 are not both always deployed, so I'd like to add dynamically the endpoints of the deployed system only.
I know I can use ReactiveHealthContributorRegistry to add custom health check endpoints dynamically. Is there a similar way for a fully custom endpoint?
Thanks in advance.
It seems there is no way to construct such complex endpoints like what I asked in Spring Boot Actuator.
I finally decided to use RouterFunction and HandlerFunction referring to the following websites.
https://www.baeldung.com/spring-5-functional-web
https://spring.io/blog/2016/09/22/new-in-spring-5-functional-web-framework

How to enable cross-origin in spring -boot for micro-services

I have nearly 5 spring boot applications which are connected to discovery service to communicate with each other. and also I want to expose some controllers to the public, so how can I enable cross-origin? should I do it in all controller level or from discovery? Any other suggestion Please!
Use the #CrossOrigin annotation either on your controller classes or on each of your controller methods that you want to permit.
You can also create a WebMvcConfigurer Bean in one of your configuration classes where you can establish cross origin configuration at a global level.
Edit: I like #peekay suggestion as well.
I have used Kong Api Gateway in front of all services. To enable cross origin.its very easy to do it in single place rather than in every single controller

Dynamically register hystrix commands without javanica annotations in spring boot

We have developed a software proxy based on spring boot and zuul, that is meant to govern services within our integration layer. We do not own the systems consuming the various services, nor do we own the actual services themselves. The services are SOAP based webservices at present. We make use of pre, post , error and route filters. Validations are database driven, including which client is allowed to call what webservice. All service definitions reside in the database (request endpoint, request xsd, response xsd, which clients are allowed to invoke, etc.).
The aim now is to add hystrix commands to handle service failures, as well as a hystrix dashboard.
The standard way to use hystrix commands involves annotating service methods with javanica. Is there a way to dynamically declare/register hystrix commands for these webservices at runtime after reading the configurations from the database? The hystrix interception will need to happen based on the multiple webservice endpoints being invoked from a single point.
Hoping this is achievable ...if not, I would really appreciate any alternative proposals for how hystrix commands could be declared in this way.
Thanks!
You're saying that you are already using Spring Boot and Zuul. How are you mapping the routes? Through the url param? Then you'll have to enroll your own. But if you define the routes as ribbon services and pass the routes as ribbon servers as described in the documentation you will get Hystrix for free.

Spring Enterprise Application Best Practices

After read the Gordon's article about Best Practices to build Enterprise Application using Spring Framework, I would like to share some ideas about the Service layer.
My architecture represents exactly what Gordon described in this image http://gordondickens.com/wordpress/wp-content/uploads/2012/07/Spring-App-Layers.png
The application is complex, has a heavy business rule and demands to use different resources like Database, SOAP, REST and file handle sometimes in the same use case.
For this scenery that I have described above, I have a Service class that needs to perform SOAP and REST requests and handle some database data. So, I have autowired in my Service class a SOAP and a REST component and the Repository to handle the database stuff.
I'm concerned about if this is the best approach do handle the integration between my Services and the resources like SOAP, REST, Database and etc.
Thanks
So, I have autowired in my Service class a SOAP and a REST component
and the Repository to handle the database stuff.
Sounds problematic even though it will work.
Think about the dependency between layers. Service layer will depend on Repository layer (Business logic layer will depend on data layer). Service integration layer (or service communication layer) for incoming requests will depend on the Service layer. But the data layer does not depend on the service layer. Nor the service layer depend on the inbound service invocation layer.
So, remove the SOAP and REST components from the Service class. To the SOAP and REST components, wire the Service instance (i.e. avoid SOAP and REST components wired into the Service, do it in the reverse direction).
This way, when you want to support another integration protocol (say JMS), you do all such work not by modifying your service.
Your data access seems to be fine. I hope your Service accesses the repository via DAOs.
So, I have autowired in my Service class a SOAP and a REST component
and the Repository to handle the database stuff.
Sounds fine. You are using dependency injection, this means they can be easily tested or altered.

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