Nowadays you can’t walk into an IT department without hearing discussions about containerization. Should we move to OpenStack or OpenShift? Do we want to use Pivotal Cloud Foundry? What about Docker Swarm or Kubernetes? How to integrate our new kubernetes cluster into our CI/CD pipelines?

ScalaDays 2019 is alweer een week voorbij, maar langzaam, maar zeker krijgt de enorme hoeveelheid hoge-kwaliteit input hun gevolgen in mijn kennis over Scala.

Today I’ve been working exactly minus 23 days at JDriven. So as you might expect, officially I’ll be starting there at the first of July. For my new employer, this is no reason at all not to invite you on the seminars they provide for their people, so yes this proved as well there is a reason to make this next step into choosing for JDriven. So last Thursday there I headed to headquarters at Nieuwegein for a full day workshop about Microservices, given by nobody else than Sam Newman!

In a previous post we learned about setting the value of options attribute to nowrap on listing and literal blocks, so the lines in the block are not wrapped. In the comments a user suggested another option to disable line wrapping for all listing and literal blocks in the document by using the document attribute prewrap. We must negate the document attribute, :prewrap!:, to disable all wrapping. If we place this document attribute at the top of our Asciidoctor document it is applied for the whole document. We can also place it at other places in the document to change the setting for all listing and literal blocks following the prewrap document attribute. To enable wrapping again we set :prewrap: (leaving out the exclamation mark).

Since Gradle 5 we can easily use a bill of materials (BOM) in our build file to get recommended dependency versions. The dependency versions defined in the BOM are dependency constraints in Gradle. This means the dependencies we define in our build that are part of the BOM don’t need a version, because the version is resolved via the dependency constraint that is defined in the BOM. Also transitive dependency versions are resolved using the BOM if applicable. We use the dependency handler method platform to define the BOM we want to import. The versions in the BOM are recommendations. We can override the recommendation by specifying the version for a dependency found in the BOM with an explicit version.

From Maven builds we know the dependencyManagement section in our POM file. In the section we can describe dependencies with their version and later in the dependencies section we can refer to the dependency without the version. We can use dependency constraints in Gradle to do the same thing. A dependency constraint can be used to define the version or version range for a dependency defined in our scripts or a transitive dependency. Just like a dependency the dependency constraint is defined for a configuration, so we can fine tune the constraints to the correct configuration.

I like to create immutable classes. When using lombok we can easily create immutable classes.

With the release of Asciidoctor 2.0.0 we get nice help on the basic syntax of Asciidoc with the command-line option --help syntax. This gives us samples of the syntax in Asciidoc markup. As mentioned by Dan Allen on Twitter we can pipe the syntax sample to Asciidoctor itself to get a HTML page:

Micronaut can convert String values defined as a number followed by (case-insensitive) KB/MB/GB to a number value in certain cases. The conversion service in Micronaut supports the @ReadableBytes annotation that we can apply to a method parameter. Micronaut will then parse the String value and convert it to a number. The value 1Kb is converted to 1024. We can use this for example in a configuration class or path variable in a controller.