README.md

SETUP ECLIPSE DITTO FOR AIWATCH PROJECT

Utilities

You can find:

• [highly recommended] Eclipse Ditto v 2.4 documentation here to understand the operations carried out below but also to understand how to do other operations.
• Eclipse Ditto repository here.
• Examples of using Eclipse Ditto here.

BASIC OPERATIONS TO DO

1. Open a new terminal and go in AI_WATCH_B1/ditto_kafka/commands
2. Create a new policy

curl -X PUT 'http://localhost:8080/api/2/policies/aiwatch:policy' -u 'ditto:ditto' -H 'Content-Type: application/json' -d @policy.json

3. Create a new digital twin

curl -X PUT 'http://localhost:8080/api/2/things/digitaltwin:Laboratorio_Corridoio' -u 'ditto:ditto' -H 'Content-Type: application/json' -d @digitaltwin.json

4. Create a new kafka connection source from user "nginx:ditto" (A1 Module - Tracker)

curl -X POST 'http://localhost:8080/devops/piggyback/connectivity?timeout=10' -u 'devops:foobar' -H 'Content-Type: application/json' -d @create_connectionSource.json

5. Create a new kafka connection target to user "ditto:observer" (Software streaming anomaly detector)

curl -X POST 'http://localhost:8080/devops/piggyback/connectivity?timeout=10' -u 'devops:foobar' -H 'Content-Type: application/json' -d @create_connectionTarget.json

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Javascript Mapping Functions used

Below is shown on several lines the mapping function "mapToDittoProtocolMsg()" in javascript of the file connectionSource.json

AI_Watch_B1/ditto_kafka/commands/[VIEW ONLY] mappingsource.js

Lines 3 to 15 in 8be8fbd

	function mapToDittoProtocolMsg(headers, textPayload, bytePayload, contentType) {
	const jsonString = String.fromCharCode.apply(null, new Uint8Array(bytePayload));
	const jsonData = JSON.parse(jsonString);
	const thingId = jsonData.thingId.split(':');
	const value = {
	coordinates: {
	properties: {
	}
	}
	};
	Object.assign(value['coordinates'][['properties']], jsonData);
	return Ditto.buildDittoProtocolMsg(thingId[0], thingId[1], 'things', 'twin', 'commands', 'modify', '/features', headers, value);
	}

Below is shown on several lines the mapping function "mapFromDittoProtocolMsg()" in javascript of the file connectionTarget.json

AI_Watch_B1/ditto_kafka/commands/[VIEW ONLY] mappingtarget.js

Lines 3 to 9 in 8be8fbd

	function mapFromDittoProtocolMsg(namespace, id, group, channel, criterion, action, path, dittoHeaders, value, status, extra) {
	let jsonPayload = value.coordinates.properties;
	let textPayload = JSON.stringify(jsonPayload);
	let bytePayload = null;
	let contentType = 'text/plain; charset=UTF-8';
	return Ditto.buildExternalMsg(dittoHeaders, textPayload, bytePayload, contentType);
	}