Camunda Trip in Node.js / Docker with variables

This is the source code of the same sample Camunda process as https://github.com/berndruecker/flowing-trip-booking-saga-c-sharp but with the following differences and additional features:

• external tasks written in node.js (using https://github.com/camunda/camunda-external-task-client-js library)
• added a parallelized version of bpmn (through parallel gateway)
• added the handling of state variables (with process variables defined within the startup REST call)
• complete with some docker-ready scripts (bash for running locally, Dockerfile to build images and docker-compose.yml to run with Swarm)

Camunda variables

For simulating a real use-case, I used the following variables:

• hasDrivingLicence: bool
• hasPassport: bool
• carBooked: bool
• flightBooked: bool
• hotelBooked: bool
• errorMessage: string

The first two represent the documents possessed by user. It's mandatory to have: any one between Driving Licence and Passport to book the hotel, the Driving Licence to reserve the car and the Passport to book the flight. The errorMessage simply contains an explaination about the cause of a failure.

To instance this variables, one should launch http://127.0.0.1:8080/engine-rest/process-definition/key/FlowingTripBookingSaga/start with the following body:

{
 "variables":{
   "hasDrivingLicence" : {
     "value" : true,
     "type": "Boolean"},
   "hasPassport" : {
     "value" : true,
     "type": "Boolean"
    },
   "carBooked" : {
     "value" : false,
     "type": "Boolean"
    },
   "flightBooked" : {
     "value" : false,
     "type": "Boolean"
    },
   "hotelBooked" : {
     "value" : false,
     "type": "Boolean"
    },
   "errorMessage" : {
     "value" : "",
     "type": "String"
    }
 },
 "withVariablesInReturn": true
}

Notice the first two variables can be, arbitrarily, assigned true or false. Because Camunda Community Edition doesn't permit to read the value of the variables after the execution of the entire process, I added two dummy user tasks in order to break the execution and read the values through the "process-instance/{id}/variables" REST API.

Containers

Each of the three external tasks, corresponding to the folders "Car", "Hotel" and "Flight", are ready to be containerized with docker image (node.js) and executed locally. Camunda image, instead, has to be properly downloaded from the official Docker repository.

One way to run the images is through the commands stored into "scripts" folder (be careful and take a look inside: for the moment these files are not well organized).