The OpenIMIS backend is split into 2 main components:
- the online services, directly supporting user interactions
- the batch (or long running) processors
OpenIMIS Online BE
The online services follow an event-driven architecture where plugins are decoupled by use of an (internal) bus.
The online services are primarily dedicated to be deployed as one (eventually clustered) instance. Yet the event-driven / internal bus architecture choice allows a smooth transition (should the load require it) to (containerised) microservices: the bus would have to be extracted as autonomous component.
OpenIMIS Online BE core provides:
- building blocks to address topics such as:
synchronous/asynchronous messages (events) to/from other Software components and other OpenIMIS plugins
- transversal features related to:
- security (authorisation)
- transaction and error management
Each OpenIMIS Online BE plugins are standardised to
- expose (automated) REST Api (aligned to DHIS2 way of working?)
- allow built-in or overloaded extensibility
- implement ORM and database migrations
All OpenIMIS Online BE features are implemented as plugins of the OpenIMIS online BE Core (following the same principle as for OpenIMIS Web FE).
Plugins are documented in OpenIMIS Modules.
OpenIMIS Batch BE
The batch processors don't follow a event-driven architecture but are implemented as workflows that are scheduled, monitored,...
As all other OpenIMIS components, OpenIMIS Batch BE is split into a core component and plugins.
The OpenIMIS Batch BE core provides:
- building blocks to address topics such as:
- parallelism, pause/resume, retry-on-error,...
- transversal features related to:
- security
- transaction, error management
- reporting and alerting
Each OpenIMIS Batch BE plugins reuse the model (and ORM) of the OpenIMIS Online BE plugins.