topic Re: Activiti Engine in Alfresco Archive

Activiti Engine

tizo — Mon, 08 Nov 2010 20:58:50 GMT

Hi there,In the company I work for, we are interested in using Activiti, but we don't really know where to start reading to design a proper solution for our environment. Particularly, we don't know what would be the best way to deploy the Activiti Engine.We have some JEE projects running in GlassFis

Re: Activiti Engine

jbarrez — Tue, 09 Nov 2010 17:15:15 GMT

Both options are possible (ie independent or in a webapp).

It depends on your use case: do you want your processes to call EJB logic?
Or doy you want to manipulate workflows from those EJB's ?
(or a combination of both)

Re: Activiti Engine

tizo — Tue, 09 Nov 2010 18:02:42 GMT

We want to manipulate the workflows from ours EJB's.

Re: Activiti Engine

jbarrez — Wed, 10 Nov 2010 07:38:20 GMT

he easiest aproach is probably using Activiti as pojo in your EJB logic.
What could be interesting is, is storing the processEngine bean and/or services in jndi and have them autoinjected.

Re: Activiti Engine

tizo — Wed, 10 Nov 2010 13:32:27 GMT

I was thinking in create an engine instance in a method annotated with @PostConstruct and destroy it (if it is necessary) in a method annotated with @PreDestroy. With this solution, there would be as many Activiti Engine instances, as there were EJBs instances. Would be a problem that all the engine instances access the same DB?.

jbarrez, how the engine could be stored in JNDI?

Re: Activiti Engine

tizo — Wed, 10 Nov 2010 20:59:43 GMT

Ok, I have the engine working, having created an instance in a @PostConstruct method. I could make some tests with that, and the first thing that I have to say is that I like Activiti very much: it is easy to configure and make it work. As for that, I have some more questions/ideas.

1- The same old question: which would be the best way to use Activiti in our environment?. jbarrez give an interesting idea of storing the engine in jndi and have them autoinjected. How could that be done?.

2- Transactions: the user guide says "Currently only supports configuration by passing the jdbc properties (datasource through JNDI will be supported soon).". So I guess that Activiti manages its owns transactions. In my case, we are using JTA; CMT more precisely. That means that I can inject a datasource (having a JNDI name), and it act as any other transactional resource (for example, an Entity Manager using JPA), letting the container to manage the transactions. It would be good that I could pass this datasource to the engine to use it. Note that I think (maybe am I wrong?) that if the engine obtain a datasource through JNDI, it should manage the transactions too, so is not the same case.

3- DB schema: is there a way to choose on which DB schema Activiti tables should be created?.

Thanks very much,

tizo

Re: Activiti Engine

jbarrez — Fri, 12 Nov 2010 08:30:48 GMT

I actually wouldnt use an engine/EJB: every engine has its own cache so your loosing some memory there by adding them to every EJB.

Regarding your questions:

1) I dont know for Glassfish, but in JBoss you have an annotation (or configuration, dont know exactly) that makes your logic execute on booting the server. That way you can create an bind your process engine to jndi.

2) That's not supported with the plain engine (altough 'naked' JTA / jndi datasource are high on our TODO list). However, you can use Spring for the moment and use the JTaTransactionManager and JNDI datasource wrappers there

3) When providing the database 'type' when you create the process engine, it automatically selects the right DDL script. Or do you mean that you want to delete some tables?

Re: Activiti Engine

tizo — Mon, 15 Nov 2010 13:51:54 GMT

1- Ok. I will try it in GlassFish. I am posting any advance.

2- Ok. It is not an option here to use Spring. As I said before, I think that if the engine obtain a datasource through JNDI, it should manage the transactions too (maybe I am wrong here?). On the contrary, we would like that our transactions (CMT ones) to be used by the engine. Anyway, for now we will try to call the engine methods exactly before finishing our EJBs method, and rollback our transactions in case an exception is caught here.

3- What I tried to mean here is if I can choose the DB schema to be used by Activiti tables. We are using PostgreSQL, and the tables are created right, but in the "public" schema. We have our DB organized in different schemas, so we would like the Activit tables to be in "activiti" schema. Of course I could change de DDL script, but I should change something more for the engine to know where the tables are.

Thanks very much,

tizo

Re: Activiti Engine

jbarrez — Mon, 15 Nov 2010 20:04:59 GMT

2) That might work, but is not yet tested in our QA environment (and also not documented)

3) Yes, you can just add the tables to any schema (at least when I tried it manually here using pgadmin)

Re: Activiti Engine

tizo — Wed, 26 Jan 2011 17:26:58 GMT

Just in case that someone is interested in this topic, answers for 1 and 2 can be found in the following thread (for Activiti 5.1): http://forums.activiti.org/en/viewtopic.php?f=6&t=922

Re: Activiti Engine

jelies — Thu, 12 May 2011 15:53:06 GMT

Hello,

I'm interested in more details for 3) question. I have integrated Activiti with my Spring container without problems, and I'm able to run the application with the Activiti tables inside the default schema. The application tables are in a specific schema (called 'SMRI').

Is there any way to specify the schema name somewhere to create Activiti tables inside the 'SMRI' schema? Because I tried to move them manually, but then my application is unable to find activiti tables and raises "table not found" exceptions.

Thanks in advance! Congratulations Activiti, you're doing a very good job!

PS: I'm using H2 database (postgresql in a near future), Spring 3.0.5, and JBoss 5.1.0.

Re: Activiti Engine

frederikherema1 — Fri, 13 May 2011 09:59:35 GMT

The schema your tables are in, are determined by your jdbc URL… So you should just change this one in your spring-datasource configuration (activiti.cfg.xml) or Jboss container datasource you're using.

Re: Activiti Engine

jelies — Fri, 13 May 2011 17:50:32 GMT

Thank you frederikheremans, you have given me a good hint to find the solution. I have modified the jdbc URL in the application's database.properties file, in case of H2 database I have to append the schema name on the URL:


database.url=jdbc:h2:tcp://localhost/<databaseName>;SCHEMA=<schemaName>

Now it works perfectly! In the next few days I will try it with postgre, I guess the workaround would be similar.

Thanks again!

Re: Activiti Engine

vaibhavkulkar — Mon, 10 Mar 2014 12:09:50 GMT

I am new to activiti and learning BPM overall. (I have similar task at hand as in this post.) Is there any quick guide documentation around this ?.
The task at my hand is to separate Activiti Engine from Activiti UI. Activiti Engine will work in seprate JVM on a seprate Machine and Activity UI will reside on a Tomcat server on a different machine.

Re: Activiti Engine

jbarrez — Tue, 11 Mar 2014 12:32:39 GMT

Sure this is possible, but you won't be able to use the Activiti Explorer UI. That one does not use the REST API, but the Java API.

Having a separate Activiti engine running in a different JVM (with a REST api?) is simple: just include it as a jar and start coding. or use the out of the box Activiti REST api.

Re: Activiti Engine

vaibhavkulkar — Thu, 13 Mar 2014 13:59:48 GMT

Thanks for reply, some more questions:
1. If not activiti explorer then can we deploy Modelling Components(Activiti modeller) and Engine separately ?
2. From performance point of view do we have any benchmark of Activiti engine Memory utilization, CPU utilization with X amount of Load.

Thanks again for reply.

Re: Activiti Engine

jbarrez — Mon, 17 Mar 2014 08:55:01 GMT

1. You can extract the Modeler from Explorer, but you'll have to do that yourself.

2. These are already quite old, but still relevant:
http://www.jorambarrez.be/blog/2012/06/28/the-activiti-performance-showdown/
http://www.jorambarrez.be/blog/2013/02/04/activiti-memory-usage/

Re: Activiti Engine

vaibhavkulkar — Thu, 20 Mar 2014 06:54:52 GMT

Thanks a lot for your valuable inputs.

As I progress I will keep posting more questions.

Re: Activiti Engine

bpmnc_user — Thu, 20 Mar 2014 07:17:56 GMT

hey Joram,

Regarding the point 1, when you say "extract the Modeler from Explorer, but you'll have to do that yourself", If I am correct, you're talking about using the Explorer app leaving the OOB UI out and apply custom UI.

What If i just want to work with the modeler and don't want to deploy the explorer. How can I use the Modeler module alone to get the editor UI working in my custom web app and not via explorer app. Would appreciate if you can guide/provide a set of detailed instructions, as was promised by Tijs a while back.

Thanks

Re: Activiti Engine

jbarrez — Mon, 24 Mar 2014 12:58:50 GMT

@bpmnc_user: No, i mean literally ripping it out yourself. All editor code is under the /editor folder in the explorer-webapp module (https://github.com/Activiti/Activiti/tree/master/modules/activiti-webapp-explorer2/editor).

You need some REST calls too specifically for the editor, which are also defined in the activiti-explorer module (see https://github.com/Activiti/Activiti/blob/master/modules/activiti-webapp-explorer2/src/main/java/org/activiti/rest/explorer/application/ExplorerRestApplication.java).