pgaijin66/mongodb-transactions

mongodb-transactions

mongodb-transactions

mongodb-transactions

Dependencies

1. Docker

2. MongoDB Atlas Account

3. Go

4. Gin

Requirement

Please configure environment variable MONGO_URL before running the code.

eg:

export MONGO_URL="MONGODB_CONNECTION_STRING_HERE"

Running project

1. Install dependencies: go mod tidy

2. Running the server: go run main.go

How it works

Here's how MongoDB transactions are implemented in this project:

1. Initialization and Connection to Database:

   The MongoDB client is set up and connected to the local database my_database. A session context is created for the MongoDB session.

2. Placing an Order (placeOrderHandler function):

   • When a POST request is made to /place_order, the server first attempts to bind the request JSON to the PlaceOrderRequest struct.

   • A session is started, and a new context for the session is created.

   • A transaction is initiated with specified read and write concerns.

   • The user ID and order amount are extracted from the request.

   • The user's balance is updated by decrementing it by the order amount. An order document is created with the provided details and the current timestamp.

   • The order document is inserted into the orders collection.

   • If any step fails, a custom error handler function handleTransactionError is called to abort the transaction and return an error response.

3. Error Handling:

   The handleTransactionError function takes care of aborting the transaction and sending an error response in case of any transaction-related error.

4. Getting All Orders (getAllOrdersHandler function):

   When a GET request is made to /orders, the server retrieves all orders from the orders collection.

5. Getting All Users (getAllUsersHandler function):

   When a GET request is made to /users, the server retrieves all users from the users collection.

6. Creating a New User (createUserHandler function):

   When a POST request is made to /users, a new user document is inserted into the users collection.

7. Starting the Server:

   The Gin router is set up with the defined routes, and the server is started on port 9090.

This project demonstrates how to use MongoDB transactions to ensure data integrity when performing related operations, such as placing an order and updating user information simultaneously.