contract-engine-edge

README

Contract Engine Edge

This repository represents the Contract Engine, a Connector between KOSMoS Global and the Edge. The main task is to create Kubernetes custom resources (using the Custom Resource Definition CRD KosmosKubeEdge) based on the received active contracts from KOSMoS Global. These custom resources are then persisted into a Kubernetes cluster.

Quickstart

1. Build the connector via make or:

go build -o contractEngineEdge ./

1. Verify Tests are working via

go test ./...

1. Update Configuration File with parameters. See below Configuration Section

2. Run contract Engine with

./contractEngineEdge

Under the Hood

The Contract Engine serves as a connector between KOSMoS Global and the Edge. For this purpose, the Contract Engine periodically retrieves KOSMoS Contracts from KOSMoS Global via a cron job. The following three steps are performed:

1. All contracts are obtained by sending a GET-HTTP request to KOSMoS_GLOBAL_HOST/contractEngine/allContractInstances . The response JSON looks like mock_contract_list.json

2. Then the contracts are filtered by the attribute activated==1.

3. For the activated contracts, KosmosKubeEdge (Kubernetes Custom Resource) objects are created. These are stored in the Kubernetes cluster.

Configuration

The Configuration of the application will be made through the file mock_contract_engine_parameters.toml. Configuration for Keycloak,Harbor and KOSMoS_Global are needed. Configuration parameter for MQTT and database are optional, as they are not used as of now. The configuration parameters will be explained in the next four subsections

Keycloak

The application uses Keycloak for authentification. Therefore it is required to setup Keycloak before.

parameter	default value	description
keycloak_url	NULL	url where keycloak instance is running
keycloak_username	edge-user	username used for authentication
keycloak_pw	edge-pw	password used for authentication
keycloak_client	kosmos-global	client that gets used for authentication
keycloak_secret	NULL	secret used for authentication

KOSMoS_Global

The Contract-Engine-Edge is dependend on a running KOSMoS_Global instance to get the current contracts.

parameter	default value	description
host	NULL	host Adress where KOSMoS_Global is running
user	NULL	username to log in
password	NULL	password of username
schema_pull_frequency	120	how often new image is pulled from harbor (in minutes)
contract_check_frequency	10	how often controller checks if contract is active (in minutes)
contract_publish_frequency	30	how often contract gets published on edge (in minutes)

MQTT

parameter	default value	description
host	mqtt-broker.kosmos-local	host where MQTT Broker is Running
port	1883	port where MQTT Broker is running
keepalive	60	maximum time interval that is permeitted to elapse between finishing transmitting one Packet and the point it starts sending the next.
user	NULL	username of MQTT-Client
password	NULL	password of MQTT-Client
blockchain_topic	""	topics where blockchain messages are received
analysis_topic	""	topics where analysis message are received

Database

parameter	default value	description
user	kosmos-local	username for db accesss
password	db_pass	password of username
database	kosmos_contracts	name of db
host	postgres.kosmos-local	host where db is running
port	5432	post where db is running