Camunda Community Day: @CamundaBPM technical sessions

I’m a few weeks late completing my report on the Camunda Community Day. The first part was on the community contributions and sessions, while the second half documented here is about Camunda showing new things that could be used by the community developers in the audience.

First up was Vladimirs Katusenoks, core developer on, with a presentation on bpmn-js: how it works, and how to extend it with custom functionality such as adding color to BPMN diagrams, which is a permitted extension to BPMN XML. His live coding presentation showed changing the colour of a shape background, either statically in code for the element class or by adding a colour picker to an individual element context palette; this was based on the bpmn-js core BPMN functionality, using bpmn-moddle to read/write into the metamodel and diagram-js to render it. There are a number of other bpmn-js examples on Github.

Next, Felix Müller discussed KPI management, expanding on his August blog post on the topic. KPI management is based on quantitative indicators for process cycle-time improvement, including cycle time and overdue time, plus definitions of the time period, unit of measure and calculation method. In Camunda, KPIs are defined in the Modeler, then monitored in Cockpit. He showed how to use the concept of element templates (that extend core definitions) to create custom fields on collaboration object (process) or individual tasks, e.g., KPI unit (hours, days, minutes) and KPI threshold (number). In Cockpit, this appears as a new tab for KPI Overview, showing a list of individual instances and target/current/average duration, plus an indicator of overdue status of the instance and any contained tasks; there is also a decorator bubble on the top right of the task on the process model to show the number of overdue instances on the aggregate model, or overdue status as a check mark or exclamation on individual models. The Cockpit modifications were done by creating a plug-in to display KPI statistics, which queries and calculates on the fly – a potential performance problem that might be improved through pre-aggregation of statistics. He also demonstrated how to modify this basic KPI model to include an expected duration as well as maximum duration. A good start, although I think there’s a lot more that’s needed here.

Thorsen Lindhauer, a Camunda core BPM developer, discussed how to contribute to the Camunda open source community, both at (engine and desktop modeler, same as the commercial product) and (JS tools). Possible contributions include answering questions on forums; logging error reports; documenting ideas for new functionality; and working on code. Code contributions typically start by having a forum discussion about planned new functionality, then a decision is made on whether it will be core code (higher quality standards since it will become part of the commercial product, and will eventually be maintained by Camunda) versus a community extension; this is followed by ongoing development, merge and release cycles. Camunda is very supportive of community contributions, even if they don’t become part of the core product: community involvement is critical to the health of any open source project.

The last presentation of the community day was Daniel Meyer discussing the product roadmap. The next release, 7.6, will be on November 30 – they have a strict twice-yearly release cycle. This release includes updates to DMN, CMMN, BPMN, rolling updates, Cockpit features, and UI/UX in web apps; I have captured a few notes here but see the linked roadmap for a more complete and accurate description and the online documentation as it is rolled out.

  • DMN:
    • Simpler decision table editing with drop-down lists of comparison/range operators instead of having to remember FEEL or Juel syntax
    • Ability to add list of selection values (advanced mode still exists for full flexibility)
    • Decisions with literal expressions
    • DMN engine performance 4-6x faster
    • Support for decision requirements diagrams/graphs (DRD/DRG) that can link decision tables; visualization in Modeler and Cockpit are not there yet but the structures are supported – in my experience, this is typical of Camunda, which builds and releases the engine capabilities early then follows with the visualization, allowing for a quicker start for executable diagrams
  • CMMN:
    • Modeler now completely models CMMN including technical attributes such as listeners
    • Cockpit (visualization still incomplete although we saw a brief view) will allow linking models of same or different types
    • Engine feature and functionality improvements
  • Rolling updates allow Camunda process engine to be updated without shutdown: guaranteed backwards compatibility of database schema to allow database to be updated first, then roll updates of engines by taking each offline individually and allowing load balancer to reroute sessions.
  • BPMN:
    • BPMN conditional event supported
    • Improved modeling including labels, collapsing/expanding subprocesses to switch between view types, and field injections in property panel.
  • Cockpit:
    • More flexible/granular human task monitoring
    • New welcome page with links to apps (Cockpit, Tasklist, Admin), user profile, and frequent links
    • Batch operations (cancel, suspend, etc.) based on batch action capability built for instance migration
    • CMMN and DMN DRD visualization

Daniel discussed some other minor improvements based on customer feedback, plus plans for 2017, including a web modeler for collaborative BPMN, CMMN and DMN modeling via a SaaS offering and a future on-premise version. They finished the day with a poll and community feedback to establish priorities for future versions.

I stayed on for the second day, which is actually a separate conference: BPMCon for Camunda’s enterprise (commercial) customers. Rather, I stayed on for Neil Ward-Dutton’s keynote, then ducked out for most of the rest of day, which was in German. Neil’s keynote included results from workshops that he has done with executives on digital transformation, and how BPM can be used to create the bridges between the diverse parts of a digital business (internal to external, automated to people-centric), while tracking and coordinating the work that flows between the different areas.

Disclaimer: Camunda paid my travel expenses to attend both conference days. I was not compensated in any way for attending or for writing this post, and the opinions here are my own.

Camunda Community Day: community contributions

Two years ago, I attended Camunda’s open source community day, and gave the opening keynote at their enterprise user conference the following day. I really enjoyed my experience at the open source day, and jumped at the chance to attend again this year – and to visit Berlin.

The first day was the community day, where users of Camunda’s open source software version (primarily developers) talk about what they’re doing with it, plus some of the contributions that the community is making to the project and updates from Camunda on new features on the horizon. To break this up a bit – since I’m already a week after the conference and want to get something out there – I’ll cover the community sessions in this post, then the Camunda technical sessions and a bit about the enterprise conference in a later post.

The first presentation was by Oliver Hock of Videa Project Services, demonstrating robot control using a LEGO Mindstorms robot to solve a Rubix cube. He showed how they used BPMN to define movements and decision tables to determine the move logic, then automated the solution using Camunda BPM. Although you may never want to build a robot to solve a Rubix cube, there are a lot of other devices out there that, like the Mindstorms robot, are controlled via Java APIs; Hock’s design showed how these Java-enabled devices can make use of higher-level modeling constructs such as BPMN and decision tables.

Next up was Jan Galinski of Holisticon to show the Spring Boot community code extension – an example of how the community of Camunda open source users give back to the open source project for everyone’s benefit. Spring Boot is a microservices framework allowing for fast deployment of web applications with a minimal amount of overhead; the Spring Boot starter extension to Camunda allows for using Camunda without a Java application server to essentially provide Camunda apps as microservices. The extension, consisting of about 5,000 lines of code, has been developed over two years with 10 contributors, including both community and Camunda contributors. Galinski showed a live coding demo of replacing JBoss server with Spring Boot starter in a Camunda application to show how this works; he has also written a post on the Camunda community site on the 1.3.0 version of Camunda BPM Spring Boot for more technical details. Although granualar process apps such as this are easier from a devops perspective in terms of deployment and scalability, the challenge is that there is no single point of entry for an end user to look at a worklist (for example). We saw some methods for dealing with this, where a workload service collects information from individual process services with the help of the Camunda BPM Reactor plugin and aggregates them; a federated task list is under development to bring together tasks from multiple process servers into a single list, with a simple completion form. Galinski walked through the general architecture for this, and noted that they are working on making this an official extension. Update: Jan Galinski pointed out in the comments that it was Simon Zambrovski  (also of Holisticon) who did the portion on the presentation on cloud, universal tasklist and event processing — I missed the transition and his name in my hasty note-taking.

Jarl Friis of the Danish tax authority (SKAT) presented their use of the Camunda decision engine: they are using only decision services, and not the BPM capabilities, which likely makes them unusual as a Camunda customer. There are a couple of applications for them: first is to raise data quality in financial reporting to the IRS (for FATCA requirements), where they receive data from Danish financial institutions and have to process it into a specific XML format to send to the IRS. Although many of the data cleansing and transformation rules are in the XML schema definitions, some are not amenable to that format and are being defined in DMN decision tables instead. As this has rolled out, they see that decision tables give them an easier way to respond to annual rule changes, although their business people are not yet trained to make changes to the decision tables. That has resulted in developers having to make the decision table changes and test the results, which is one of the challenges that they have had to deal with: some of the developer test frameworks replicated the original decision table logic in code, which effectively tested the decision table implementation rather than the business logic. That test framework, of course, no longer worked when the decision table was changed, and Friis’ message to the audience was that organizations have to deal with challenges of ownership and responsibility for rules as well as rules testing.

Niall Deehan of Camunda gave a great presentation on on modeling anti-patterns: snaking models that are often used to fit models onto a single sheet of paper (instead, use model with happy path down the centre from left to right); inappropriate use of BPMN versus CMMN (e.g., voting scenarios); inappropriate use of BPMN versus process engine or Cockpit capabilities (e.g., service call with error exceptions for null pointer, bad response, service down); too many listeners on tasks (masks problems and pushes process logic into code, based on concept that analysts’ model should not be changed). He discussed some best practices for consistency: define the symbol set to be used by your analysts and lock down the modeler to remove elements that you don’t want people using; create and maintain your own best practices documentation; use model templates for commonly used activities; and proper training. I would love to see his presentation captured for replay: it was engaging and informative.

The last community presentation was Martin Schimak of plexiti, showing three community extensions used for automating testing of BPMN and CMMN models.  Assert checks and sets the status of tasks in order to drive a process instance through a test scenario. Process Test Coverage visualizes test process paths and checks process model coverage ratio, as covered by individual test methods and entire test classes (e.g., using mockito). Assert Scenario is for writing robust test suites for process models; this was not covered in Schimak’s demo due to time contraints, but you can read more about it on his blog.

Before we started on the Camunda technical presentations, the community award was presented by Camunda as a reward for contributions on extensions: this went to Jan Galinski from Holisticon. It’s really encouraging to see the level of engagement between Camunda and their open source community: Camunda obviously realizes that the community is an important contributor to the success of the enterprise version of the software and the company altogether, and treats them as trusted partners.

Disclaimer: Camunda paid my travel expenses to attend both conference days. I was not compensated in any way for attending or for writing this post, and the opinions here are my own.