EF Core Two-Phase Commit Demo (.NET 8 + Docker)

This sample demonstrates a Two-Phase Commit (2PC) style transaction using .NET 8 and Entity Framework Core. It simulates a bank transfer between two separate SQL Server instances running in Docker containers.

2PC-Demo/
├── src/
│   ├── Contexts/           # Database context classes
│   │     BankAContext.cs
│   │     BankBContext.cs
│   │
│   ├── Models/            # Entity models
│   │     Account.cs
│   │
│   ├── Data/             # Database initialization
│   │     DbInitializer.cs
│   │
│   ├── Services/         # Business logic
│   │     BankTransferService.cs
│   │
│   ├── Program.cs        # Application entry point
│   ├── appsettings.json  # Configuration
│   └── TwoPhaseCommitDemo.csproj
│
└── docker-compose.yml    # Docker configuration

• Two-Phase Commit pattern implementation
• Automatic database initialization and seeding
• Simulated failure scenario for testing rollbacks
• Clean separation of concerns (services, data, models)
• Detailed console logging with Serilog

docker-compose up -d

Wait until both containers are healthy:

docker ps

Success scenario:

cd src
dotnet run

Failure scenario (simulates error after first commit):

cd src
dotnet run --fail

1. On startup:

   • Creates both databases if they don't exist
   • Seeds initial test accounts:
     • BankA: Account1 with 1000
     • BankB: Account2 with 500

2. During transfer:

   • Attempts to transfer 100 from BankA to BankB
   • Uses transaction coordination to ensure consistency
   • Either both operations succeed or both rollback

3. In failure scenario:

   • Simulates error after BankA update
   • Demonstrates automatic rollback
   • Ensures data consistency across both databases

• Uses SQL Server instances:
  • BankA on port 1433
  • BankB on port 1434
• Data is reset on each run for clean demo
• Uses TransactionScope for coordinating transactions
• Detailed logging shows each phase of the 2PC process

• Ensure Docker containers are running and healthy
• Check if ports 1433 and 1434 are available
• Verify SQL Server connection strings in appsettings.json
• Look at console logs for detailed error information