README.md

Booking Demo

This demo simulates a ordering application including three services:

• ordering
• inventory
• payment

Prerequisites

You will need:

1. JDK 1.8
2. Maven 3.x
3. Docker
4. Docker compose
5. alpha server

Running Demo

You can run the demo using either docker compose or executable files.

via docker compose

1. run the following command to create docker images in saga project root folder.

   mvn clean package -DskipTests -Pdocker -Pdemo
   

2. start the whole application up(including alpha server and three demo services)

   ./saga-demo.sh up
   

   Note: If you prefer to use MySQL as alpha's backend database, you need to try the following steps instead:

   1. add dependency of mysql-connector-java in alpha/alpha-server/pom.xml

          <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
          </dependency>

   2. remove alpha server's docker image

      docker rmi -f $(docker images | grep alpha-server | awk '{print $3}')

   3. re-generate saga's docker images

      mvn package -DskipTests -Pdocker -Pdemo

   4. start application up in saga-demo/booking with the following command

      ./saga-demo.sh up-mysql
      

   Note: If you want start alpha server and demon services separately, you can try the following steps:

   1. start alpha server

          ./saga-demo.sh up-alpha

   2. when alpha server started complatelly, then start the demo services

          ./saga-demo.sh up-demo

3. stop application

   ./saga-demo.sh down
   

via executable files

1. run the following command to generate executable alpha server jar in alpha/alpha-server/target/saga/alpha-server-${saga_version}-exec.jar.

   mvn clean package -DskipTests -Pdemo
   

2. follow the instructions in the How to run section in User Guide to run postgreSQL and alpha server.

3. start application up

   1. start inventory service. The executable jar file should be in saga-demo/tcc-spring-demo/inventory/target/saga.

   java -Dserver.port=8081 -Dalpha.cluster.address=${alpha_address}:8080 -jar tcc-inventory-${saga_version}-exec.jar

   2. start payment service. The executable jar file should be in saga-demo/tcc-spring-demo/payment/target/saga.

   java -Dserver.port=8082 -Dalpha.cluster.address=${alpha_address}:8080 -jar tcc-payment-${saga_version}-exec.jar

   3. start ordering service. The executable jar file should be in saga-demo/tcc-spring-demo/ordering/target/saga.

   java -Dserver.port=8083 -Dalpha.cluster.address=${alpha_address}:8080 -Dinventory.service.address=${host_address}:8081 -Dpayment.service.address=${host_address}:8082  -jar tcc-ordering-${saga_version}-exec.jar

User Requests by command line tools

1. Ordering 2 units ProductA with the unit price 1 from UserA account, this ordering will be OK.

curl -X POST http://${host_address}:8083/ordering/order/UserA/ProductA/3/1

Check the Inventory orders status with

curl http://${host_address}:8081/orderings

Check the Payment transaction status with

curl http://${host_address}:8082/transactions

2. Since the initial value of the payment of UserC is 1. Ordering 2 units of ProductA with the unit price 2 from UserC account , this ordering will cause the payment failed and trigger the cancel operation with inventory ordering.

curl -X POST http://${host_address}:8083/ordering/order/UserC/ProductA/2/2

Check the Inventory orders status with

curl http://${host_address}:8082/orderings

Check the Payment transaction status with

curl http://${host_address}:8081/transactions

The second order will be marked with cancel:true

Debugging

To debug the services of the demo, just add debug parameter to JVM through the environment field in docker-compose configs. Let's take alpha-server as an example:

alpha:
  image: "alpha-server:${TAG}"
  environment:
    - JAVA_OPTS=-Dspring.profiles.active=prd -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005
  ports:
    - "6006:5005"
...

We append the debug parameter -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005 to the JAVA_OPTS environment variable, the Java process inside the container will listen on port 5005. With the port forwarding rule 6006:5005, when alpha-server is ready, we can connect to port 6006 on the host and start debugging alpha-server.

If you're using IntelliJ, open the saga project, create a new debug configuration with template 'Remote', fill "Host" and "Port" input with "localhost" and "6006", then select "alpha" in the drop-down list of "Use classpath of module". When alpha-server is running, hit shift+f9 to debug the remote application.