PDA Architecture

This document describes the components that comprise the Process Driven Applications (PDA) plugin architecture with respect to deployment, as well as how they interact with each other.

The image below shows the high level components.

PDA MFEs

The PDA micro frontends run on the browser, rendering the custom UI components the user interacts with. These components are written in React and fetch data from the PDA API, passing the Keycloak token for authentication.

The MFEs also make calls to the Entando Core API to retrieve the settings required for the UI configuration. These components are available to assist with page creation after the PDA plugin bundle is installed.

The source code for this component: https://github.com/entando/entando-process-driven-plugin/tree/master/widgets (opens new window)

PDA API

The PDA API is a Spring Boot application that communicates with the BPM engine, and BPM engine data is made available in a Rest API. Subject to deployment configuration, the PDA API interacts with Keycloak to validate the token, retrieving the connection and sensitive data. Instead of calling specific engine classes directly, the application calls the abstractions defined in the PDA Core library.

The engine implementation is determined at runtime based on the connection details provided. It is important to note that the PDA API does not have a database and is therefore stateless. All data available in the API are retrieved from the BPM engine. After bundle installation, the API is deployed as a microservice in the Kubernetes infrastructure. An Ingress is also created to make the API available to the MFEs, as described by the Entando Plugin custom resource.

The source code for this component: https://github.com/entando/entando-process-driven-plugin (opens new window)

PDA Core

The PDA Core is the library that defines the interface and abstraction implementations that interact with specific BPM engines. It allows multiple engine implementations to exist simultaneously.

The source code for this component: https://github.com/entando/pda-core-engine (opens new window)

PAM Impl

The PAM Impl is the Red Hat PAM implementation for the PDA Core library. If the connection maps to a PAM engine, these are the classes that are executed when the PDA API requests engine operations. This implementation communicates with the Kie Server, which executes the defined process operations.

The source code for this component: https://github.com/entando/pda-redhatpam-engine (opens new window)