I know compile time and runtime. when I read Spring-Data reference, I read this
"If the repository infrastructure does not find a declared query for the method at bootstrap time, it fails"
when is bootstrap time?
Most spring projects are bootstrapped - meaning that they are ready for Spring Boot.
Spring-boot's "Bootstrap time" refers to when the application is loading all the Auto Configures.
Related
I'm working on creating a kogito bpm spring boot project. I'm very happy to see reduced level of complexity on integration on jbpm in spring boot with the help of KOGITO. I'm struggling to find answers for my question, so posting them here,
Kogito is a open source cloud offering for jbpm. I'm I correct?
I see only mongodb or infinispan can only be used or supported with Kogito. I can't integrate psql with kogito. I'm I correct?
I successfully created the spring boot kogito mongodb project and when I placed a .bpmn file in the resource folder, automatically endpoints got created. I was able to access, run the process and get response. But I don't see any entries created in MONGODB :| I don't even see the table being created. The .bpmn contains a simple hello world flow with start+scripttask+end nodes. Please explain help me understand this. Is the RuntimeMangar configured for per request stratergy? How can I change it?
Answers inline.
Kogito is a open source cloud offering for jbpm. I'm I correct?
Kogito is open-source and has jBPM integrated into its codebase to run on a cloud-native environment. In addition, a lot has been made to make it also run with native compilation if used with Quarkus.
I see only mongodb or infinispan can only be used or supported with Kogito. I can't integrate psql with kogito. I'm I correct?
To this date, Kogito has the following add-ons to support persistence:
Infinispan
Postgres
MongoDB
JDBC (so you can extend to support any database you wish)
See more about it here https://docs.jboss.org/kogito/release/latest/html_single/#con-persistence_kogito-developing-process-services.
But I don't see any entries created in MONGODB
Do you mind sharing a reproducer? Have you taken a look at the examples in https://github.com/kiegroup/kogito-examples/tree/stable/process-mongodb-persistence-springboot? This example shows a call to a sub-process that relies on a user task. Hence the process must be persisted to fire up again on a new request to solve the task. However, since your process starts and ends in one request, there's nothing to be persisted in the DB:
Runtime persistence is intended primarily for storing data that is required to resume workflow execution for a particular process instance. Persistence applies to both public and private processes that are not yet complete. Once a process completes, persistence is no longer applied. This persistence behavior means that only the information that is required to resume execution is persisted.
Our application environment in Websphere Application Server has 3 clusters
1. UI Cluster
2. Service Cluster
3. Integration Cluster
We have around 50 war files (Micro Services) deployed to Service cluster. All services are REST based and exposed through SPRING API. Restarting Service cluster takes close to 30 mins. This time is critical during live incidents in Production. For reasons, if Service cluster needs to be restarted, we need to have 30 mins downtime for all end users. We are looking to reduce to recycle time, please suggest us for any solution.
Is there a way to load all the Spring based jar files before the application starts?
i.e. for example there is a service war file called as xyz-1.0.war and there are Spring based jar files as maven dependencies. All 50 number of WAR files has the same set of dependencies, I am thinking in a way to see if we can load all the Spring based jars before the application is started by websphere server.
Please suggest.
I don't know that you can load them BEFORE the application starts (class loading is generally on-demand), but you might be able to speed things up through the use of shared libraries for your common files, so they'd be loaded by a single class loader rather than from each WAR's class loader. It won't eliminate the class loading activity, since each WAR would still need to load the necessary classes, but it'd speed up the mechanics of the class loads since the shared library loader would return the already-loaded class rather than searching its class path.
There are two different approaches you could take to this. Step one in both cases is to create a shared library with the classes that are shared among the applications. The options for step two:
1) Create a custom class loader on the server and associate the shared library with this new class loader. This will make the classes in the shared library visible to all applications running on the server.
2) In the shared library configuration, select "Use an isolated class loader for this shared library", then associate the shared library with any applications that require it. In the event that the shared classes are required only by some applications, this will provide them only to the applications that require them.
A couple points of caution:
If you require unique Class instances (for example, static values unique to each WAR), this approach won't work, because there will be only one instance of the Class loaded by the shared library loader. In that event, you'll have to stick with WAR-level packaging.
If you use the isolated class loader solution, note that those loaders use "parent last" class loading, in which they are searched before server class loaders. If you have anything in those libraries that conflicts with classes provided by the server, it could open you up to ClassCastExceptions or LinkageErrors.
Note that the shared library loaders operate as parents of the WAR loaders, and as such, classes in the libraries will not be able to "see" classes in the WARs. You'll need to make sure that the libraries are essentially self-contained in order for these approaches to be successful.
More specific details on the configuration steps can be found in this blog post: https://www.ibm.com/developerworks/community/blogs/aimsupport/entry/create_shared_library_and_associate_it_with_the_application_server_or_application_on_websphere_application_server?lang=en_us
If you are doing microservices then your services should be independently deployable, so they each should be in the separate cluster. Traditional WebSphere Application Server is a bit heavy weight for this solution (depending on how many resources you have on your nodes), so I'd suggest you to migrate your service cluster to WebSphere Liberty and in that case you could have each service in separate clusters. This would allow you to restart each service independently, at much shorter time.
If you are doing microservices, then your UI cluster should be prepared for any service unavailability - that is a primer when doing microservices, and display some message to end user, that this service is temporary unavailable.
Regarding your current setup - you could try the "Rollout update" option, which will restart your server sequentially, so services should be available on other nodes.
so-random-dude advice to use blue/green deployment is also very good. You could have 2 cells, and then switch plugin configuration after redeployment. If your services are written in a way that different versions can run in parallel during update, you would have no downtime.
If you want to reduce downtime further and improve performance, you should consider using Java EE/Rest services instead of Spring, as it will cut down significantly size of your app, amount of libs to be scanned, deployment and startup time. It is much better integrated and supported in WebSphere Liberty than tons of jars that you have to include with Spring.
I have a simple solution for you, just ditch the Websphere and deploy those 50 "wars" as independent jars with embedded netty/undertow/tomcat/jetty in it.
I am afraid, what you have currently is not at all a microservice architecture. Agreed, different teams/consultants/organizations has different interpretation of "micro"services. But this is an extreme, which you should avoid at any cost; because you are having all the pain points of microservice and ZERO benefits (benefits such as independent scalability/deployability etc).
Restarting Service cluster takes close to 30 mins. This time is
critical during live incidents in Production. For reasons, if Service
cluster needs to be restarted, we need to have 30 mins downtime for
all end users
Have you looked at different deployment strategies like Canary deployment / Blue-Green deployment? Do you have more than one instances behind a load balancer?
Pardon if I can't give more pointers, but I'm really a noob at wildfly. I'm using version 9.0.2.
I have deployed jbpm-console, drools, and dashboard - no problems here. I restart wildfly using the jboss CLI, and when I login again, the repositories won't appear in the web interface or on disk (atleast nothing that grepping or find will show).
I'm using the H2 database. I'm not even sure where to look, does anyone have any idea?
Thanks in advance!
After enough reading through the docs, it would seem that it's necessary to configure jBPM to persist. From the docs:
"By default, the engine does not save runtime data persistently. This means you can use the engine completely without persistence (so not even requiring an in memory database) if necessary, for example for performance reasons, or when you would like to manage persistence yourself. It is, however, possible to configure the engine to do use persistence by configuring it to do so. This usually requires adding the necessary dependencies, configuring a datasource and creating the engine with persistence configured."
https://docs.jboss.org/jbpm/v5.3/userguide/ch.core-persistence.html
I have started working with ZK recently. I really like the framework but I am having a lot of problems in configuring it to work correctly with Websphere Application Server v8.0. Namely, I am developing an EJB application with accessing the database via JPA entities and using the ZK framework for GUI. I am developing the application using the Rational Software Architect 8.5.
When I start working on a fresh ZK project in a fresh workspace and server profile everything seems to be working correctly. However, after some time I start having strange problems. I think the problem occurs in the moment when ZK tries to initialize my ViewModel class. I do not get any exceptions or errors, but get the timeout message in my browser: "The page or component you request is no longer available. This is normally caused by timeout, opening too many Web pages, or rebooting
the server."
My ViewModel initializes by resolving the EJB bean I am using for business logic. That normally works, but as I said, after working for some time on the project, or after restarting my computer the ViewModel object cannot get initialized and the timeout error appears no matter what I do (when ZK tries to bind a variable or when I fire an event needed to be handled by my ViewModel. As before, I do not get any additional errors or exceptions.
Has anybody already had this problem? Is there a solution? Can I change the configuration of my server or ZK to avoid this problem?
Thank you.
Seems that I have solved the problem myself. I was using internal Rational Software Architect (Eclipse) browser which apparently has problems handling ZK sessions. When I switched to Firefox, the problems I explained stopped appearing.
I am new to jboss and would like to know what are the differences between ServiceMBean and load-on-startup servlet tag in web.xml? Also, I would like to know which one will always get loaded first or they are loaded at the same time? In what situation, I should use MBean and when I should use startup servlet or it doesn't matter?
I need to write a a class/servlet to validate if all the required system properties (e.g -DINSTALL_DIR=blah ) is set. If not, then stop right there. else proceed and start the application.
Thanks in advance
-A
ServiceMBean is JMX, it is part of your JVM. load-on-startup servlet tag in web.xml is part of your J2EE application.
JMX is part of J2SE starting from JDK 1.5. So, you can have one ServiceMBean per JVM. not per application. JMX is used mostely for monitoring and managing the JVM. It provides access to information such as: number of classes loaded and threads running, memory consumption, garbage collection statistics, on-demand deadlock detection, and others. Another common use, is to refresh your cache.
JMX will allow you to instrument your application and control/monitor it using what-ever management console that your JMX container supports. An example would be a web application that implements a reference data cache...
A problem we had before was we would occasionally need to refresh the cache because a customer name changed in the database. If we had a refresh method on the MBean interface then we should be able to trigger this event using the JMX console. The JMX console may be a web or fat client that comes with our J2EE server. Our J2EE server may also support SNMP. This means that we may be able to invoke the method from a standard Tivoli or UniCenter console.
http://www.theserverside.com/news/1364664/J2EE-Application-Management-The-Power-of-JMX
You don't need remote access to ServiceMBean in order to trigger some asynchrious action. Moreover, you need validation on scope of application, not the whole JVM (while, you can, theoretically, handle this issue in the ServiceMBean). So, it is more naturally, to do it as load-on-startup servlet tag in web.xml. In this way, in every start up of your application validation will happen.
One more clarification: ServiceMBean is JBoss-way to write JMX. All MBeans are server wide (not application wide). That's why I use MBean and ServiceMBean freely above.