Temporal Projects samples

Technologies Used:

• Language: Java
• Build Tool: Maven
• Framework: Temporal
• Infrastructure: Docker compose

This project contains two sample applications using Temporal to orchestrate workflows:

• one is a banking application
• the other is an e-commerce order processing application

Please note that this applications do over simplify functional features that real application should provide. There are only a pretext to demonstrate Temporal.io features.

The project also includes configurations to run temporal in a Docker environment. (see docker-compose.yml in the src/main/docker directory).

Running temporal server

To run the temporal server, you can use the provided docker-compose configuration:

cd src/main/docker
docker-compose up

• The Temporal server will start on localhost:7233.
• The Web UI will be available at http://localhost:8088. You can use the Web UI to monitor the workflows and activities.

Banking Application

1. Workflows and Activities:

   • BankingWorkflowImpl: Implementation of the banking workflow, managing deposit, withdrawal, and balance checking.
   • BankingActivitiesImpl: Implementation of the activities associated with the banking workflow.

2. Workers:

   • BankTransferWorker: Starts a Temporal worker to execute banking workflows and activities.

3. Starter:

   • BankTransferStarter: Starts a banking workflow with specific parameters (account ID, initial balance, deposit amount, withdrawal amount).

4. workflow description

   The workflow manages the transfer of money between two bank accounts. Here are the main steps of the workflow:
   Debit the Account: Debits the specified amount from the source account. If the activity fails (insufficient funds), the workflow stops.

   Credit the Account: Credits the specified amount to the destination account. If the activity fails (e.g., account blocked), handles the error and refunds the source account.

   Error Handling:

   • If funds are insufficient, logs the error and throws an exception.
   • If the account is blocked, logs the error, refunds the source account, and throws an exception.
   • The workflow uses retry options for the activities, with maximum attempts and backoff intervals configured.

Running the Banking Application

1. Ensure temporal server is started:
2. Start the Worker:
   • Run the BankTransferWorker class to start a worker that executes banking workflows and activities.
3. Start the Starter:
   • Run the BankTransferStarter class to start a banking workflow.
   • The workflow will execute the steps of the banking workflow.

E-commerce Order Processing

1. Workflows and Activities:

   • OrderWorkflowImpl: Implementation of the order workflow, managing stock reservation, payment, stock checking, shipping, and cancellations.
   • OrderActivitiesImpl: Implementation of the activities associated with the order workflow.

2. Workers:

   • ECommerceWorker: Starts a Temporal worker to execute order workflows and activities.

3. Starter:

   • ECommerceStarter: Starts an order workflow with specific parameters (order ID, product ID, quantity).

4. Stock Notification:

   • StockAvailableNotifier: Notifies the running workflow that stock is available by searching for running OrderWorkflow instances.
   • This code also shows how to search for workflow instances:

Running the E-commerce Application

1. Ensure temporal server is started:
2. Start the Worker:
   • Run the ECommerceWorker class to start a worker that executes order workflows and activities.
3. Start the Starter:
   • Run the ECommerceStarter class to start an order workflow.
   • The workflow will execute the steps of the order processing workflow.
   • You can also, if necessary, run the StockAvailableNotifier to notify the workflow that stock is available.

Testing the Applications

• Run the tests in the src/test directory to test the workflows.