OCEAn

Description

Welcome to ProCel, a web app to work with object-centric event logs (OCELs). ProCel's main features are

• Importing OCELs (OCEL 2.0 sqlite format)

The project consists of

• A backend running on Python 3.10, mostly using FastAPI, pandas, pm4py, pydantic and pint,
• A frontend based on React / Next.js, using React Bootstrap elements.

Installation

via Docker

Docker support will be added shortly.

Default

Backend: using pypoetry, when inside /src/backend, dependencies can be installed with

poetry install

Frontend: using npm, when inside /src/frontend, dependencies can be installed with

npm install

Usage

Backend and frontend are started using the following two commands in separate terminals:

python main.py
npm run dev

After starting, the app can be accessed at http://localhost:3000. To get started, try loading one of the event logs listed on the start page.

Repository structure

• src/backend:
  • api: FastAPI config, API models
  • ocel: OCEL 2.0 Wrapper class, attributes & utils
  • util: Misc util functions
  • visualization: Mostly used for evaluation (+OCPN rendering)
• src/frontend:
  • components: React components
  • pages: React page components & main app
  • public: Images
  • src: reusable TypeScript functions & type definitions
    • src/api/generated: API handlers & types generated by openapi-ts
• data:
  • event_logs: Example OCELs

Details

App state

User inputs made in the frontend are automatically passed to the API and saved in the Session object. This way, sessions are preserved when refreshing. Sessions are identified via a UUID and saved in the browser's localStorage.

The inputs (called AppState) include

• object type colors
• object type classes (Handling units / resources)

API

FastAPI generates an openapi.json file following the OpenAPI standard. When the backend is running, API docs can be accessed at http://localhost:3000/docs/rapidoc.

All types passed along the API are defined in the backend using pydantic models. pydantic handles validation and serialization of these data structures. API routes defined in src/backend/index.py are automatically passed a current Session and OCELWrapper instance. The current OCEL is further used in custom validators of ModelWithOcel subclasses. This way, when sending an emission rule it is automatically checked whether an attribute name that is used exists in the OCEL. When using only parts of the implementation, run

from api.model.with_ocel import ocel_ctx
ocel_ctx.set(ocel)

to make the validators access a current OCEL instance via a context variable.

The frontend accesses the API via code generated by the openapi-ts package. When making changes to the backend, run npx openapi-ts in src/frontend with the backend running to re-generate.

Authors and acknowledgment

Author: Raimund Hensen

This project has been developed for my master's thesis at the Chair of Process and Data Science (PADS) at RWTH Aachen University under the supervision of Nina Graves and Prof. Wil van der Aalst.

License

see license document.