Eclipse Ditto 3.2.0
Eclipse Ditto 3.2.0 focuses on the following areas:
- New History API in order to be able to:
- access historical state of things/policies/connections (with either given revision number or timestamp)
- stream persisted events of things/policies via async APIs (WebSocket, Connections) and things also via existing SSE (Server-Sent-Events) API
- configure deletion retention of events in the database for each entity
- Addition of new Eclipse Hono connection type for Ditto managed connections
- Option to do case-insensitive searches and addition of a new RQL operator to declare case-insensitive like: ilike
- UI enhancements:
- Push notifications on the Ditto UI using SSE (Server-Sent-Events), e.g. on thing updates
- Autocomplete functionality for the search slot
- Added configuring Bearer auth type for the "devops" authentication
- Support for "merge" / "patch" functionality in the JS client
The following non-functional work is also included:
None in this release.
The following notable fixes are included:
- Undo creating implicitly created policy as part of thing creation if creation of thing failed
Ditto's codebase is implemented in Java. By default Java objects are mutable which does not work well in highly scalable, message driven architectures, as possible side-effects during runtime may occur when concurrently modifying objects. Because of that the Ditto team decided to use immutable objects wherever and whenever possible. Immutablity of the objects is ensured in unit tests.
Ditto's model modules and also the Ditto Java client are OSGi bundles so that they may be used in OSGi environments without much effort. The model modules are configured to be checked by a "binary compatibility checker" in the Maven build so that APIs are not broken unintentionally.
On a level higher than the model, Ditto uses a microservice based architecture. As Ditto's microservices are interacting via an event driven approach, Ditto provides a very modular setup on the microservice level meaning that single services must be not started at all if their functionality is not needed. Another benefit from this architecture is that the services may be scaled horizontally if more resources are required.
Ditto utilizes the CQRS and EventSourcing pattern and mainly uses "inserts" (append only) into the database in favor to "updates" in order to get a better performance when doing database writes. The only exception is the "search" microservice which uses traditional CRUD in order to update its search index.
There are no security issues known at the time of this writing.
Ditto comes with:
- A project site containing the documentation (including basic concepts, architecture, definition of the Ditto Protocol, etc.)
- A "Hello World" example
- An OpenAPI based HTTP/REST documentation and applied HTTP concepts
- A GitHub repository with ditto-examples
- A Blog with the latest examples tutorials, release announcements, etc.
- Presentations of Ditto
- A sandbox installation where Ditto can be tried out without setting it up locally
Ditto is able to process AMQP 1.0, AMQP 0.9.1, MQTT 3.1.1 and MQTT 5 messages which are all standardized (IoT) protocols.
Ditto can use JSON Web Tokens specified by RFC 7519 in order to extract "subjects" (e.g. a user-id) to use for the access control to twins.
Ditto's API documentation is defined using the OpenAPI specification 3.0.0 allowing both creation of an interactive HTML-based documentation and creation of skelettons for various programming languages based on that specification.
Ditto supports the W3C Web of Things (WoT) Thing Description 1.1 standard.
Users of Ditto ask their questions via these channels:
- The Gitter chatroom of Ditto
- Via GitHub discussions for questions and general discussions
- A Stackoverflow tag "eclipse-ditto" on which community quersions are answered by our committers
- The mailing-list (email@example.com) is not actively used and watched
Ditto seeks for a good integration with Eclipse Hono in order to being able to create digital twins for all devices connected via Hono. The Ditto team is also in regular discussion with the Hono team.
Some of the Ditto team are committers in the Eclipse IoT Packages project aiming to simplify deployment and integration between Eclipse Hono and Ditto and additionally to showcase the integration with other OSS IoT projects.