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MicroProfile LRA Parallel Execution Evaluation

This project includes an example implementation of the Saga pattern using MicroProfile LRA. The difference to the original Saga Pattern Realization with MicroProfile LRA is the parallel execution of specific tasks instead of a sequential one.

Start the Application

  1. Run ./gradlew clean build

  2. Execute docker-compose up

  3. Requesting trip bookings is now possible. Either use curl commands, the provided TravelApplication.json insomnia file, which includes different trip booking requests, or access the Swagger UI of the different services:

    Service URL to Swagger UI
    TravelService http://localhost:8090/openapi/ui/
    LRA Coordinator (included in TravelService)
    HotelService http://localhost:8081/openapi/ui/
    FlightService http://localhost:8082/openapi/ui/

An example for such a request:

TravelRequest
{
    "duration":
    {
        "start":"2021-12-01",
        "end":"2021-12-12"
    },
    "start":
    {
        "country":"Scotland",
        "city":"Stirling"
    },
    "destination":
    {
        "country":"Sweden",
        "city":"Stockholm"
    },
    "travellerName": "Max Mustermann",
    "boardType":"breakfast",
    "customerId":"1"
}

To simulate a Saga that fails because no hotel or no flight is available, use one of the following Strings as destination country in the trip booking request:

"Provoke hotel failure"

"Provoke flight failure"

The services also provide a general health endpoint that shows information about the system whether it is up and running. These endpoints can be accessed via:

Service
URL to health endpoint
TravelService http://localhost:8090/health
HotelService http://localhost:8081/health
FlightService http://localhost:8082/health

If you are on Windows or Mac, you sometimes have to replace localhost with the default IP of your docker machine ( use docker-machine ip default to get this default IP).

Stop the Application

To stop the application and remove the created containers, execute the following command:

docker-compose down --remove-orphans

Parallel Execution of Tasks

The bookHotel and the bookFlight requests, as well as the confirmHotel and the confirmTrip requests, are now executed in parallel by asynchronously invoking the endpoints. However, the confirmTrip request is responsible for ending the LRA. Therefore, it can only be executed in parallel with requests that will always succeed. Additionally, the LRA Coordinator invokes the compensations, so this execution cannot be influenced.

MicroProfile_Implementations/MicroProfile_ParallelExec-Evaluation

Last update: 2022-02-15
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