trip-manager-springboot

About

TMM LRA demo , demonstration of a Java microservice for trip management built on the SpringBoot framework. Default TRM LRA coordinator URL is "http://localhost:9000/api/v1/lra-coordinator"

Trip-Manager service information

This trip-manager application exposes two REST endpoints. Both endpoint business logic remains same, while only difference is with the order of calling the LRA participants for booking.

Endpoint	Resource Class	Description
/trip-service/api	TripManagerResourceAsync.java	Call LRA particiapnts Hotel and Flight asynchronously
/trip-service/api/sync	TripManagerResource.java	Call LRA particiapnts Hotel and Flight sequentially

Below configurations are required to use Spring Boot @Async feature and call the participants asynchronously

Executor Configuration

Since Spring Boot @Async methods executes in isolated thread, we need to explicitly set the LRA context within executor thread by implementing TaskDecorator interface and initializing it in executor configuration. There is a predefined TaskDecorator already present int MicroTx library for this purpose. It is present under package com.oracle.microtx.springboot.lra.context and MicroTxTaskDecorator is the decorator class.

Custom named bean has to be defined for executor configuration to avoid conflicting with other executor configurations and MicroTxTaskDecorator task decorator has to be set. Refer to AsyncConfiguration.java

@Bean(name = "taskExecutorForTripBooking")
    public Executor asyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        ...
        executor.setTaskDecorator(new MicroTxTaskDecorator());
        ...
        return executor;
    }

Note: If there is already a user defined task decorator present with some logic and needed to be used in same Executor config, then user can override the MicroTxTaskDecorator and accommodate along with the changes or refer to MicroTxTaskDecorator class and make the same changes in your custom task decorator.

LRA specific methods which are marked @Async should use the executor with the exact bean name. In this instance, the bean name is @Bean(name = "taskExecutorForTripBooking") Refer to BookingServiceImpl.java

@Async(value = "taskExecutorForTripBooking")
public CompletableFuture bookHotel(String name, String id) {
    ...
}

@Async(value = "taskExecutorForTripBooking")
public CompletableFuture bookFlight(String flightNumber, String id) {
    ...
}

NOTE: If the LRA Initiator (trip-manager) is calling LRA participants (Hotel and Flight) in sequential order, above Executor configuration is not required. Please refer to TripManagerResource.java

Quick Start

To run build:

mvn clean package

To run the application:

java -jar target/trip-manager-sb.jar

To run the application with different TRM coordinator assign the URL to mp.lra.coordinator.url system variable:

java -jar -Dmp.lra.coordinator.url=<url> trip-manager.jar

To create a docker image:

docker image build -t=<image_name> .

To run the docker image:

docker container run <image_name>

To run the docker image with different TRM coordinator assign the URL to MP_LRA_COORDINATOR_URL environment variable:

docker container run -e MP_LRA_COORDINATOR_URL=<URL> <image_name>