The scheduler is responsible for scheduling the execution of tasks. The execution of those tasks are being prioritized / scored by a ranker. The tasks are then pushed onto a priority queue.

Within the project of KAT, the scheduler is tasked with scheduling boefje and normalizer tasks.


See architecture document for the architecture and the extending document for the extending the scheduler with your own custom schedulers, and rankers.

Stack, packages and libraries








Used for api server



External services

The scheduler interfaces with the following services:




Retrieving random OOI’s of organizations


Used for referencing available plugins and organizations


Retrieve last run boefje for organization and OOI


Sending boefje, and normalizer tasks to Celery


Used for retrieving scan profile changes, and created raw data in bytes

Project structure

$ tree -L 3 --dirsfirst
├── docs/                           # additional documentation
├── scheduler/                      # scheduler python module
│   ├── config                      # application settings configuration
│   ├── connectors                  # external service connectors
│   │   ├── listeners               # channel/socket listeners
│   │   ├── services                # rest api connectors
│   │   └──
│   ├── context/                    # shared application context
│   ├── models/                     # internal model definitions
│   ├── queues/                     # priority queue
│   ├── rankers/                    # priority/score calculations
│   ├── repositories/               # data abstraction layer
│   ├── schedulers/                 # schedulers
│   ├── server/                     # scheduler rest api interface
│   ├── utils/                      # common utility functions
│   ├──
│   ├──
│   ├──                      # kat scheduler app implementation
│   └──                  # version information
└─── tests/
    ├── factories/
    ├── integration/
    ├── simulation/
    ├── unit/

Running / Developing

Typically the scheduler will be run from the overarching nl-kat-coordination project. When you want to run and the scheduler individually you can use the following setup. We are using docker to setup our development environment, but you are free to use whatever you want.


By the use of environment variables we load in the configuration of the scheduler. See the environment settings section under Installation and Deployment for more information.


# Build and run the scheduler in the background
$ docker-compose up --build -d scheduler


# Run integration tests
$ make itest

# Run unit tests
$ make utest

# Individually test a file
$ make utest

# Individually test a function
$ make function='test_function' utest