Event Driven Architecture

This is the project implementation for the event driven and process oriented architecture course. The project works with the provided robot simulator in the lab.

General workflow

The project will be set up in microservices and communicates via Kafka. The general idea of the process that is modelled is as follows:

A delivery service will deliver a package from a supplier to a warehouse. The warehouse has an automated inventory system. An inventory person can set the package on the predefined spot and then access the web UI to announce a delivery with the respective delivery notice. Then, the warehouse inventory system will start the process of checking the delivery. The happy-path includes:

• Each part is picked up by the robot in one of the 3x3 grid cells of the predefined location
• Then the robot places the part onto the NFC reader and associates the part with a unique ID
• The robot then places the part onto the conveyor belt
• The part on the belt is driven down to the color sensor
• The second robot will pick it up and puts it onto the color sensor
• After the color has been determined, the robot puts it back to the conveyor
• After being driven back, the first robot sorts the color onto the respective stack
• With a small chance, the orchestrator will deem a part "broken" and put it onto the broken stack

Sequence

Please take note that the event based communication is not part of the following sequence diagram. The diagram shows the happy path if all services are working correctly.

sequenceDiagram
  actor u as User
  participant i as Inventory UI
  participant o as Orchestrator
  participant p as Picker Robot
  participant belt as Conveyor
  participant c as Color Robot

  u ->> i: fill in delivery notice
  i ->> o: notify about delivery

  loop For each part
    o ->> p: get part
    p ->> belt: put onto
    belt -->> c: drive to color bot
    c ->> belt: get part
    c ->> c: check color
    c ->> belt: put back
    belt -->> p: drive back
    p ->> p: check for defects
    p ->> p: stack accordingly
    p ->> o: notfiy
  end

  o ->> i: notify

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Possible error scenarios

• In general: if a robot is not able to pick up a certain part
• If the delivery contains wrong information about the amount of parts
• If during the inventoring process, parts are lost

Process Model Information

Error Scenarios

Error scenarios are currently managed with manual intervention. We decided to wait for 5 seconds for events to occur. Otherwise a manual intervention is triggered. After resolving the last step is repeated.