I have posted my thoughts and evaluation of the jBPM 5 RFC posted last week, see the jbpm-dev list (may take a bit to appear).
I think the theme should be 'Nobody gets left behind' when working towards the jBPM future.
======================================
UPDATE: (seems to be something wrong with mailinglists, not posted yet so adding here)
Posted 23 April 2010:
============
I have been watching the replies and seeing what the jBPM core
community developers would be saying before responding with my own
thoughts on this topic.
My background with jBPM is not well documented here in the forums or
mailing lists. I have been using jBPM in an enterprise environment
over the last three years or so as both a developer and lead
developer. It started on the jBPM v3.1.x community versions and later
migrated to the current supported jBPM v3.2.x. I also have had
personal meetings with Tom, Joram and Koen discussing jBPM 3 and jBPM
4, be that development questions, use cases from customers or just my
experiences deploying enterprise solutions into production
environments. One award winning case was published
(http://www.schabell.org/2009/11/2009-silver-winner-for-europe-financial.html)
on the implementations we did with jBPM v3.
Looking at the various sections presented by Kris in the design
overview https://community.jboss.org/wiki/jBPM5RequestforComments, I
will run through each section and give my thoughts:
Architecture:
=========
This picture is clear and concise, providing a pretty good idea of
what the overview is. I miss JBoss Rules / BRMS as a block in the
Connections side. I feel that Rules is just as important as JBoss ESB
and you need to provide this to push your own products. On a side
note, the roadmap needs to come ASAP to provide clarity where the
focus is. You will see below in my evaluation, there is a focus needed
on the core functionality to make something that can make it into a
product.
Core process engine:
===============
When I look at this component I see many of the existing jBPM 4 branch
as being a strong candidate to be leveraged along with whatever the
Drools project has completed. Would be great if they could/would
compliment each other. I am very happy to see the PVM being the
leading theoretical foundations for the BPM suite. Three items are of
some note:
1) process instance migration is mentioned as if it is about stateless
processes. I do not see how you can manage this at all. If you show me
a process you think you can migrate, I bet I can break it.
2) process instance migration could and should be a target for moving
from one version of jBPM to the next.
3) jPDLv3 -> BPMN2 process definition conversion tooling is a must and
I was pushing this before the split, with project space already setup:
http://anonsvn.jboss.org/repos/jbpm/projects/migration_tool (current
leads are more than happy to have someone to help on this conversion
tool, great place to get your feet wet in open source!)
Finally, this part of the project should have about all the attention
available to ensure a speedy delivery. This is what is needed to offer
customers a path into the future of BPM.
Human Tasks:
===========
Following a standard makes lots of sense. I do see this as a bit of an
external project when related to the console and form editor. First
order of business is having them available.
Process repository:
==============
I would assume that this component could also leverage the efforts of
ModeShape project maybe? Keep work to a minimum by conforming to what
they recognize as an artefact. Seems also to fall into the category of
nice to have but not yet essential to initial releases.
BPM Console:
==========
Looks like this can and should leverage the jBPM 4.x work, the GWT
console project, along with whatever Drools project can / has to
offer. This is nice to have stuff.
Eclipse-based process tooling:
======================
To leverage jBPM 4.x existing tooling and Drools project tooling. The
extra bits mentioned are again fine for later releases.
Web-based process tooling:
====================
Is Oryx / Signavio one team? I was under the impression that Drools
went one way and jBPM project another... who will win now and what are
the criteria to be judged?
Simulation:
========
Very advanced feature that is nice to have (would make Product sales
easy to visualize and demo's very slick) but nothing to focus on in
the initial releases I would think. This could be an apart
sub-project.
BAM / BI:
======
This is a very interesting one, how to provide without dictating what
a person is to get/use/have in the BAM/BI area. It should be about
facilitating and ease of customization. Also an apart sub-project and
not important for the initial releases.
Usability:
=======
Strange mix of stuff here; Domain-specific processes (what for? why?
let's get normal process engine out there first?), install scripts
(already there?), continuous integration (leverage existing setups?),
documentation (has always been outstanding, should not slip), OSGI
(what for?).
Integration:
========
Every item mentioned here in this section needs to have a block in the
architecture overview picture. Very good to leverage and use our own
projects. Make that the easiest path.
Final thoughts, I see many panic reactions on the lists/forums with
regards to jBPM 4. Looking at this overview Kris provides, I expect
much of the jBPM 4 will function as some sort of base line for further
development. DroolsFlow will play a role and if more projects are
leveraged then this overview of a BPM suite on functionality is
achievable. I think the first steps need to be to ensure that
customers are taken from jBPM3 to jBPM5. plan this from the beginning.
Rule #1: nobody gets left behind.
Friday, April 23, 2010
Tuesday, April 20, 2010
jBPM v3.2 custom exception framework example now available
The idea is that you are now able to use a single exception handling process (see image provided) to provide all your processes with exception processing. There are only two options in this framework, a human task to allow fixing your processes problems by hand or a retry option to allow for automated continuation based on settings you define.
Currently the unit test demonstrates only human task fixing of a single node failure, but I will continue to work on this. I plan to complete a state node failure and demonstrate the Retry option.
The project includes maven dependency handling (see the pom.xml) and you can start in the readme.txt file included at the root level of the project.
Thursday, April 8, 2010
Fedora 12 Eclipse Subversion plugins missing javahl
I tend not to use the integrated Fedora 12 Eclipse packages as I want more control over my Eclipse or JBoss Developer Studio (JBDS) and Java versions. I have many Java JDK's installed and can use them easily with the alternatives setup from Fedora 12.
What I keep running into is that the local subversion packages provide Java HL in the /usr/lib64/* location and the Eclipse or JBDS Subclipse plugins are looking for them in /usr/lib/*, so how to correct this?
Now my subversion tooling in Eclipse / JBDS works without complaining...
What I keep running into is that the local subversion packages provide Java HL in the /usr/lib64/* location and the Eclipse or JBDS Subclipse plugins are looking for them in /usr/lib/*, so how to correct this?
// adding the pointer to my javahl libs in eclipse.ini file // as follows to make use of the Fedora 12 native rpm javahl // package installed libs: // -Djava.library.path=/usr/lib64
Now my subversion tooling in Eclipse / JBDS works without complaining...
Wednesday, March 24, 2010
jBPM migration strategies - Introduction
These ideas will be put forth based on the simple diagram provided here which outlines a typical enterprise business process implementation. It is not necessary to have all the various components in an implementation to be able to make use of the guidelines detailed in this article. The extensive list of components is provided to allow for discussion on the typical interactions I have encountered in my jBPM travels. In this introduction these layers will be outlined and future articles will cover them in more detail.
The idea behind each layer will be to identify best practices and ways to keep your implementations as jBPM version agnostic as possible. I believe this can be achieved, to a point, with proper knowledge and design time application of this knowledge. Each section will dive deeper into that specific area and try to provide you with the knowledge to design and implement your jBPM projects in such a way as to future proof them. You will be as ready as you can be to migrate to the next version.
The choice to focus on jBPM v3.2.x is due to the fact that this is currently the supported enterprise version provided in the JBoss SOA-P product. This is what many enterprises are currently using, throughout the world.
Process initialization layer
The first layer covers the details of providing flexible initialization of your processes within enterprises where you might have serious performance wishes, many different processes that can be initiated and allow for prioritising which process will be started when.
Process definition layer
This layer contains the process definition itself, a narrow layer that simply needs to be migrated to some future version of jBPM. Will this layer be jPDL, XPDL or some form of BPMN?
Process implementation layer
Here we dive into the underlying code layer that is best known as Handlers. The actual Java implementation that you may extended with abstraction layers, business logic and helper utilities. There is much to be cautious of here when looking to migrate your processes to a future version of jBPM, but there are some simple practices that will make migration less work than you think!
Process interaction layer
There is much to be won with a good strategy for accessing business logic, back-end systems, back-office systems, user interfaces, other applications or whatever your business processes need to use to get their jobs done. Here you will find a series of components passing review with suggestions for each one on the best way to position your projects for easy migration. A bit of prevention will go a long way in your IT budget!
General best practices
For as far as they have not been covered, I will provide some best practices with regards to any jBPM project. These will zoom in to a lower level than the above layers and can be applied across them all. If you get nothing out of these articles, I hope you will be able to make use of these gems of knowledge learned through harsh lessons in the trenches of jBPM projects.
Please feel free to provide feedback and suggestions for areas that might be missing. I am not trying to cover all possible use cases for jBPM projects, but to provide a reference architecture that is recognisable for the majority of enterprise jBPM users.
The next article in this series examines the process definition layer...
Tuesday, March 16, 2010
jBPM 3 hints - finding a process instance in your deep dark jBPMContext
While writing some unit testing of the jBPM exception framework I needed to deal with two separately deployed process instances, one for the unit test and one for dealing with the exception I was causing.
My problem was how to obtain the exception process instance when all I know is the process name? I also had it easy from the unit testing point of view, I do not need to worry about multiple running instances of the exception framework as this is under my unit test control (at least I feel like I have some control over it!).
Below you see how you can locate your process instance and context within that instance. I will show you some helper methods that might come in handy for you (all logging done with log4j and assumes you understand what you see below):
My problem was how to obtain the exception process instance when all I know is the process name? I also had it easy from the unit testing point of view, I do not need to worry about multiple running instances of the exception framework as this is under my unit test control (at least I feel like I have some control over it!).
Below you see how you can locate your process instance and context within that instance. I will show you some helper methods that might come in handy for you (all logging done with log4j and assumes you understand what you see below):
/** Used to get the process id of the specific process I want. */
public long getExceptionProcId () {
JbpmConfiguration jbpmConf = JbpmConfiguration.getInstance();
long procId;
// Open the transaction.
JbpmContext jbpmCtx = jbpmConf.createJbpmContext();
try {
// Get our process instance back.
GraphSession graphSession = jbpmCtx.getGraphSession();
ProcessDefinition processDefinition =
GraphSession.findLatestProcessDefinition("Exception Framework");
assertThat("No process definition found.",
processDefinition, is(not(nullValue())));
// Now, we search for all process instances of this process definition.
List processInstances =
graphSession.findProcessInstances(processDefinition.getId());
ProcessInstance procInst = (ProcessInstance) processInstances.get(0);
procId = procInst.getId();
} finally {
// Close context.
jbpmCtx.close();
}
return procId;
}
With the above you can make use of the processId to recall your process instance as follows: JbpmConfiguration jbpmConf = JbpmConfiguration.getInstance();
JbpmContext jbpmCtx = jbpmConf.createJbpmContext();
try {
long processInstanceId = getExceptionProcId();
ProcessInstance procInst = jbpmCtx.getProcessInstance(processInstanceId);
assertThat("No exception process instance returned.",
procInst, is(not(nullValue())));
assertThat("Exception process in unexpected state.",
procInst.hasEnded(), is(true));
} finally {
// Close context.
jbpmCtx.close();
}
Another nice one to help you find what processes have been deployed in your current jBPMContext:// find all our processes that have been deployed and log them.
JbpmConfiguration jbpmConf = JbpmConfiguration.getInstance();
JbpmContext jbpmCtx = jbpmConf.createJbpmContext();
try {
List listProcs =
jbpmCtx.getGraphSession().findAllProcessDefinitions();
if (getLogger().isDebugEnabled()) {
for (ProcessDefinition processDefinition : listProcs) {
getLogger().debug("Process definition is: "
+ processDefinition
+ " with version: "
+ processDefinition.getVersion()
+ ".");
}
}
} finally {
jbpmCtx.close();
}
Sunday, March 14, 2010
JBoss BRMS install example repository gives OutOfMemoryError: PermGen space
After server start-up you login to http://localhost:8080/jboss-brms which asks you if you want to install the sample repository in your new system. When I said yes, it would run a bit and then give me an error like this:
22:05:00,094 ERROR [STDERR] Exception in thread "http-127.0.0.1-8080-5"
22:05:00,094 ERROR [STDERR] java.lang.OutOfMemoryError: PermGen space
22:05:00,152 ERROR [ContainerBase] Servlet.service() for servlet guvnorService threw exception
java.lang.OutOfMemoryError: PermGen space
at java.lang.Throwable.getStackTraceElement(Native Method)
etc.........
To fix this you need to tweak the jboss-as/bin/run.sh by adding near the top of the file the following line:
# Set a sane PermSize. JAVA_OPTS="$JAVA_OPTS -XX:MaxPermSize=256m"
Restart EAP 4.3 and the installation of your sample repository will run fine.
Friday, March 12, 2010
Tweaking the log4j BasicConfigurator
This is not magic that I am posting, but something I don't want to sort out again in the future. My current project was involving some extensive debugging of my unit tests, with long log lines on the console causing me to have to full-screen or scroll too much (forced to work on windows and lots of mouse clicks really get my goat).
By digging into the log4j BasicConfigurator.class (with my buddy Maurice, credit to the mastermind!) it has a default setup as follows:
This will generate logging output like this:
I adjusted this in my unit tests as follows:
This will give you output like this:
By digging into the log4j BasicConfigurator.class (with my buddy Maurice, credit to the mastermind!) it has a default setup as follows:
root.addAppender(new ConsoleAppender(new PatternLayout("%r [%t] %p %c %x - %m%n")));
This will generate logging output like this:
4513 [main] DEBUG org.jbpm.graph.def.GraphElement - event 'process-start' on ProcessDefinition(Exception Handling) for Token(/) 4654 [main] DEBUG org.jbpm.graph.def.GraphElement - event 'process-start' on ProcessDefinition(Exception Framework) for Token(/)
I adjusted this in my unit tests as follows:
((PatternLayout) ((Appender) Logger.getRootLogger().getAllAppenders()
.nextElement()).getLayout())
.setConversionPattern("%r [%t] %p %c %x -%n%n %m%n%n");
This will give you output like this:
4513 [main] DEBUG org.jbpm.graph.def.GraphElement - event 'process-start' on ProcessDefinition(Exception Handling) for Token(/) 4654 [main] DEBUG org.jbpm.graph.def.GraphElement - event 'process-start' on ProcessDefinition(Exception Framework) for Token(/)
Monday, March 8, 2010
Fedora 12 NetworkManager update breaking GSM connection
My latest Fedora 12 update broke my Mobile Broadband GSM connection. I kept seeing this in my message log:
The key here was the line:
Some looking around and it appears that the last update to NetworkManager broke it:
Name : NetworkManager
Arch : x86_64
Epoch : 1
Version : 0.7.998
Release : 2.git20100106.fc12
A simple downgrade will fix this to back you up to the previous version, here is mine:
Name : NetworkManager
Arch : x86_64
Epoch : 1
Version : 0.7.996
Release : 6.git20091021.fc12
To do this you use the following command:
Restarted and the GSM card worked as advertised!
============== UPDATE 02 April 2010 =========================
See Bugzilla on this for solution of upgrading the NetworkManager and ModemManager packages
to the versions found in the test repo:
https://bugzilla.redhat.com/show_bug.cgi?id=560742
http://download.fedora.redhat.com/pub/fedora/linux/updates/testing/12/
6516 Mar 8 12:22:49 localhost NetworkManager:(hso0): device state change: 3 -> 4 (reason 0) 6517 Mar 8 12:22:49 localhost NetworkManager:Activation (hso0) Stage 1 of 5 (Device Prepare) scheduled... 6518 Mar 8 12:22:49 localhost NetworkManager:Activation (hso0) Stage 1 of 5 (Device Prepare) started... 6519 Mar 8 12:22:49 localhost NetworkManager:(hso0): device state change: 4 -> 6 (reason 0) 6520 Mar 8 12:22:49 localhost NetworkManager:Activation (hso0) Stage 1 of 5 (Device Prepare) complete. 6521 Mar 8 12:22:49 localhost NetworkManager:Activation (hso0) Stage 1 of 5 (Device Prepare) scheduled... 6522 Mar 8 12:22:49 localhost NetworkManager:Activation (hso0) Stage 1 of 5 (Device Prepare) started... 6523 Mar 8 12:22:49 localhost NetworkManager:(hso0): device state change: 6 -> 4 (reason 0) 6524 Mar 8 12:22:49 localhost NetworkManager:Activation (hso0) Stage 1 of 5 (Device Prepare) complete. 6525 Mar 8 12:22:49 localhost modem-manager: (ttyHS2) opening serial device... 6526 Mar 8 12:22:49 localhost modem-manager: Modem /org/freedesktop/ModemManager/Modems/0: state changed (disabled -> enabling) 6527 Mar 8 12:22:50 localhost modem-manager: Modem /org/freedesktop/ModemManager/Modems/0: state changed (enabling -> enabled) 6528 Mar 8 12:22:50 localhost modem-manager: Modem /org/freedesktop/ModemManager/Modems/0: state changed (enabled -> disabled) 6529 Mar 8 12:22:50 localhost NetworkManager:(hso0): device state change: 4 -> 3 (reason 0) 6530 Mar 8 12:22:50 localhost NetworkManager:(hso0): deactivating device (reason: 0). 6531 Mar 8 12:22:50 localhost NetworkManager:stage1_enable_done(): GSM modem enable failed: (32) SIM PIN required 6532 Mar 8 12:22:50 localhost NetworkManager:(hso0): device state change: 3 -> 9 (reason 0) 6533 Mar 8 12:22:50 localhost NetworkManager:Activation (hso0) failed. 6534 Mar 8 12:22:50 localhost NetworkManager:(hso0): device state change: 9 -> 3 (reason 0) 6535 Mar 8 12:22:50 localhost NetworkManager:(hso0): deactivating device (reason: 0).
The key here was the line:
stage1_enable_done(): GSM modem enable failed: (32) SIM PIN required
Some looking around and it appears that the last update to NetworkManager broke it:
Name : NetworkManager
Arch : x86_64
Epoch : 1
Version : 0.7.998
Release : 2.git20100106.fc12
A simple downgrade will fix this to back you up to the previous version, here is mine:
Name : NetworkManager
Arch : x86_64
Epoch : 1
Version : 0.7.996
Release : 6.git20091021.fc12
To do this you use the following command:
$ sudo yum downgrade NetworkManager
Restarted and the GSM card worked as advertised!
============== UPDATE 02 April 2010 =========================
See Bugzilla on this for solution of upgrading the NetworkManager and ModemManager packages
to the versions found in the test repo:
https://bugzilla.redhat.com/show_bug.cgi?id=560742
http://download.fedora.redhat.com/pub/fedora/linux/updates/testing/12/
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