Wolkenkit, an open-source JavaScript library for building event-sourcing applications based on Command Query Responsibility Segregation (CQRS), has been updated.

Wolkenkit is a CQRS and event-sourcing framework for JavaScript and Node.js which is designed to fit well with domain-driven design (DDD). It provides the technical foundation for your application, including an event-store and a scalable real-time API.The new version, Wolkenkit 3.0, includes a file storage service that was rewritten from scratch and that now supports authorization. The update also provides CLI commands to export and import your application data.

Command Query Responsibility Segregation (CQRS) is the concept that applications separate the models for reading data and updating data. Event sourcing refers to the concept that you can capture all changes to an application state as a sequence of events. This means that the events can be queried, or the event log can be used to reconstruct past states. More sophisticated usage lets you adjust the state to cope with retroactive changes.

The file storage service, dept, has been rewritten from scratch as the developers originally focused on having a simple solution, but this proved inadequate for some uses, such as those where there was a need to protect stored files against unauthorized access.

Rather than attempting to retrofit the changes, the file storage system has been completely rewritten. The new version has an authorization mechanism that integrates with the existing authentication and authorization features of Wolkenkit itself. This lets you configure access rights for your stored files in a very fine-grained way.

There's also now a client SDK for depot, which makes accessing the file storage service as simple as possible. The developers say that they have taken account of future needs to support other storage engines than the local file system, such as Minio and Amazon S3, so features like this will be able to be added without further rewrites.

Along with the rewritten storage system the developers have added two new CLI commands for exporting and importing. Exports are created as JSON files, which means that an export is not only useful as a backup, but can also be used to analyze events with third-party tools. 

Other improvements include a new landing page that avoids problems when starting a Wolkenkit application; new features in the write and read models that mean up to 256 commands can be run in parallel; and better handling of security credentials.

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Wolkenkit

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