Java Spring Boot MVC and CLI API in the same project - java

Java Spring Boot MVC and CLI API in the same project
I have implemented a web app using Spring Boot MVC and I now I need to add an API whose functions can be called from a cronjob.
I would like to use Entity and Repository classes implemented in my Web app. I was thinking about creating a new main class which implements
CommandLineRunner interface and then create separate JARS for Web and CLI applications and run them independently. Is this a good approach?
Do you have any suggestion about the architecture?
Thanks

Concur with comment from #jb-nizet - cron is really just another client of your application, and using a (bash,etc.) script wrapping curl, httpie, or wget to call the controller is a good solution.
Advantages include:
can be called remotely
doesn't add complexity to the application
application boundary/interface remains the same
doesn't add a new application (except a relatively trivial script)
not tied to cron - could be almost any other application
Considerations:
authentication (if needed) and the management of credentials in the script/cron
if all methods/actions needed for cron are new and different to existing functions in the web app, do they make sense to be encoded in the webapp?

Related

Is it possible to start up an external spring-boot application programmatically

I have created a rest application using spring-boot 2.0.3. From an other maven module (in a different multi module pom), I have an integration test that tests that data sent to the running rest application is processed.
Is it possible to run this spring-boot application programatically? I cannot use the simple #SpringBootTest-annotation as the spring-boot application is not in the same maven multi module.
I would recommend using mockito to mock a request to your rest endpoint with some data, and testing that your other application tries to send the correct data to the endpoint.
This way both applications are tested independently and do not have dependencies at each other. This provides the benefit of being able to substitute one of these applications with another if necessary. Also it provides a good separation. This is important because when you (or someone else) wants to use your REST application they do not use your other application so it is very important that the REST application is tested with static data written in your tests and is not dependent on the output of another application. Since REST applications are meant to be independent.
However, when you do want to test it this way you could try to include your other application in the classpath.
The thing is "loose coupling". It is technical possible, but not recommended. The build itself has numerous tests using where mocking with Mockito is essential.
An integration test module, ala cucumber.io, should be created which will cover the functionality of the running module.
This is the main-point of the accepted answer.

How to use Spring Boot Activity Rest api in Activity App Ui

I am new to Activity process. I want to used the Activity with spring boot application. So, I want to used the rest api in spring boot and that rest api will be used by activiti-admin.war and activiti-app.war.
So, when I have deployed process from spring boot that will be available in UI and add some Listener while assigning task will be called in my spring boot app.
Can any one help.
Thanks in advance.
It sounds like you are using the version 6 Activiti build.
Both the activiti-app and admin-app already use "a" REST API to communicate to the backend, however it is not the community REST API that will be deployed with your Spring boot application (I assume you are using the Activiti spring boot starter rest).
It is not actually going to be trivial to separate the activiti-app and admin-app UI from the service layer as they are quite tightly coupled, but it is certainly possible.
While I haven't actually attempted it, it may be easiest to take the activiti-app build module (activiti-ui/activiti-app) and separate the client and server portions since the client is now a regular AngularJS application.
Is this what you are looking for?
Thanks,
Greg
I hope you are looking for something like this. It seems they are planning to support activiti app with your own spring boot application in Activiti 7.
If you are able to solve the case, please help with the sample structure. I am bit stuck with same usecase.

Adding spring mvc to a spring java "desktop" application

I have a Java desktop application which uses spring framework and I need to replace the Swing UI with a web front end. I understand that I will need to adapt many things to make things work with the MVC architecture.
My concrete question is the following:
Will my application now have to run entirely in the application server?
I would appreciate if anyone could point me to some documentation that goes through a similar process.
Thanks!
Technically yes, but Spring Boot makes it trivial to set up an embedded servlet container and package your entire application as a runnable jar. This is how we're deploying our applications to production; the only thing we need is a JRE on the server VM, and java -jar takes care of all of it.
I recommend using Maven with the Spring Boot plugin (there's also a Gradle plugin) with the repackage goal, and using the lightweight Undertow servlet engine instead of the default Tomcat.

Self contained jar with Camel and Web Interface?

I have had lots of trobule trying to get my head around how to solve this scenario:
We have an integration application that uses Camel for integration. This application also has a REST Api that exposes some services providing information about the application, for instance listing the active routes etc.
I have created a user interface for this using AngularJS that connects to these rest services. My main problem is how can I package this application as a self contained jar-file that provides the user interface and all the camel integration.
My working theory: Use a separate Jetty server to serve the Angular JS files and let Camel expose the REST services. The problem with this is CORS since the REST services reside on another port than the jetty server serving the Web UI.
Some requirements for the solution:
Must be a single self contained jar-file.
The camel integration is the main purpose, the Web UI is secondary
and only used for trouble shooting. No need for a high performance
web container since the Web ui is used by only a handful of users.
I have been struggling with this for a couple of days now and it feels like I am over complicating the solution. Help on how to solve this is greatly appreciated.
You could take a look at hawtio
http://hawt.io/
as that is how we do that, hawtio is a web console for java, and has plugins for Camel. Its built using angularjs, and uses REST to communicate with the local or remote Java JVMs. To make the REST calls easier we use Jolokia.
Jolokia requires an agent to be embedded in the JVM, eg where Camel runs. Then that helps with CORS et all. http://jolokia.org/reference/html/security.html#d0e2490

Adding a web interface (Spring MVC) to existing Java application

I have an existing Java application (Spring based) that currently does NOT have a web interface, nor does it run in a web container. It packages up nicely with a start program and just works.
What I need to do is add an administrative web interface for some administrative type things, retrieving real time metrics, and perhaps some graphs to give the users a warm fuzzy feeling knowing that everything is working. As we are a Spring shop, and some of our web applications already use Spring MVC it only makes sense to us, however, I'm not happy with the suggestions I've had from our internal Spring folks on how I should procede.
What would be the ideal way to bolt on this web interface?
Convert my application to a web application and have a web container launch the application. I not too keen on this approach is the web tier is really secondary to the primary application.
Create a separate project that packages as a war, embed Jetty in my existing app and have it load the war. I think I can use the context loader listener to make the root context of my application the parent to the web application spring context. This would involve breaking up my Maven project into 2 projects I believe. I can't use an existing web technology for communication between the web tier and the primary application as my primary application is not web enabled.
Embed Jetty and put the Spring MVC stuff directly in my app. While I've done this approach before, it does involve some ugliness - for instance exploding the JSP tag libs into my jar.
Any thoughts on some clean separation here?
Also of note, my current jar contains some utility applications which some shell scripts launch. Going a pure WAR route would make this not so easy, since I can't juse point java at my war file and choose a class to execute.
Thanks.
If it's true that web is just a minor addition the application, migrating it to WAR and deploying in servlet container might be an overkill. Embedding web server/servlet container looks much simpler, although it doesn't have to be Jetty or Tomcat. You can use web server built into JDK or write one on top of netty or even raw sockets. But that's a hell to maintain.
Yet another solution to springs to mymind when reading:
web interface for some administrative type things, retrieving real time metrics, and perhaps some graphs
Maybe you don't need an interface, but monitoring infrastructure instead? Check out JMX (Spring has great support for JMX) - and write a second web application that simply connects to your standalone Java app via JMX and displays the metrics in fancy way. Another approach is to expose JMX via Jolokia, which translates JMX to REST services.
This approach has several advantages:
monitoring API is universal, and you get it for free
you don't have to use web client, monitoring application is completely decoupled,
finally changes to your original application are minimal. Check out this proof of concept: 1, 2.
It really depends on the structure of your existing Java/Spring app and how much of an API it provides. I've done something similar to this and I approached it by creating a separate Spring MVC project and then specified the existing Java app as a JAR dependency.
This is easy with Maven (or Ivy, etc) and provides nice decoupling. The trick is to be able to write service classes in the Spring MVC app which then access data via your dependent Spring app via a simple DAO class. That's why I stated at the beginning, that it depends on the structure of your original Java app. It has to be able to provide an API for data access that you can then plug your DAO (impl) into.
If this is not easily done, then the next option I'd suggest is simply converting your Spring app to a Spring MVC app. I've worked on another app where we did this. Using Maven, its possible to specify that the build can create either a war file or a jar file (or both). So it can be deployed as either a webapp (via war) or a normal app (via jar). Yes, the jar version has a bit of bloat but its a worthwhile compromise.
The question of embedding Jetty or using Tomcat via a war file is a completely separate issue that has its pros and cons. It shouldn't affect the approach you take in architecting the web app in the first place.

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