.NET Application Modernization Report: ContosoUniversity¶

Modernization Notes¶

1. Target Framework & Project System Modernization¶

• Port to .NET 8 (LTS): Migrated ContosoUniversity.csproj from legacy net5.0 to net8.0.
• SDK & Package Cleanup:
  • Retained the modern Microsoft.NET.Sdk.Web SDK project format.
  • Replaced legacy Entity Framework 6 (EntityFramework 6.4.4) with Microsoft.EntityFrameworkCore (8.0.11).
  • Added PostgreSQL provider Npgsql.EntityFrameworkCore.PostgreSQL (8.0.11).
  • Updated Microsoft.AspNetCore.Mvc.NewtonsoftJson to 8.0.11.
  • Retained BuildBundlerMinifier (3.2.449) to compile and minify CSS bundles during dotnet publish.
  • Removed deprecated analyzers and obsolete packages (System.ComponentModel.Annotations, System.Configuration.ConfigurationManager, Google.Cloud.Diagnostics.AspNetCore, Grpc.AspNetCore).
  • Added <EnableSourceControlManagerQueries>false</EnableSourceControlManagerQueries> to ensure reproducible builds across varied container and git reftable environments.

2. Data Layer Migration (SQL Server to PostgreSQL)¶

• SchoolContext Refactoring:
  • Migrated ContosoUniversity.DAL.SchoolContext from System.Data.Entity.DbContext to Microsoft.EntityFrameworkCore.DbContext.
  • Configured DI options via DbContextOptions<SchoolContext>.
  • Mapped entity table name explicitly in OnModelCreating (modelBuilder.Entity<Student>().ToTable("Student")).
• Database Initialization & Seeding:
  • Refactored SchoolInitializer into DbInitializer implementing context.Database.EnsureCreated() and idempotent seed data population.
  • Retained SchoolInitializer as an alias wrapper for backward compatibility.
  • At startup, the application creates the database and populates seed students if the table is empty.

• PostgreSQL Case Sensitivity & Raw SQL:

  • PostgreSQL folds unquoted SQL identifiers to lowercase, whereas EF Core creates quoted table and column identifiers.

  • Refactored the raw SQL query in StudentController.GetEnrollmentSummary from unquoted SQL to quoted identifiers:

    SELECT "EnrollmentDate", COUNT(*) AS "StudentCount"
    FROM "Student" GROUP BY "EnrollmentDate"
    

  • Switched from EF6's Database.SqlQuery<T> to EF Core 8's Database.SqlQueryRaw<T>.

• Timestamp Compatibility:

  • Enabled AppContext.SetSwitch("Npgsql.EnableLegacyTimestampBehavior", true) in Program.cs to allow seamless persistence of DateTime values (with Kind=Unspecified produced by HTML form bindings) into PostgreSQL timestamp columns.
• Exception Handling:
  • In StudentController.Create, replaced EF6 RetryLimitExceededException with EF Core's DbUpdateException and injected ILogger<StudentController> for structured error logging.
  • Removed manual Dispose override in StudentController so the scoped SchoolContext lifetime is managed by ASP.NET Core dependency injection.

3. Google Cloud Run Container Contract Compliance¶

• Port Binding:
  • Dynamically binds to http://0.0.0.0:${PORT:-8080} as required by Cloud Run.
  • Configured both ASPNETCORE_HTTP_PORTS and PORT environment variables in the container image.
• Structured JSON Logging:
  • Removed all legacy or file-based logging configurations.
  • Configured ILogger with logging.AddJsonConsole() to output single-line structured JSON logs to stdout/console for native Google Cloud Logging ingestion.
• Graceful Shutdown & Signal Handling:
  • Relies on the .NET Generic Host (Host.CreateDefaultBuilder) native SIGTERM handling and registered a structured logging lifecycle listener on IHostApplicationLifetime.ApplicationStopping for clean shutdown.
• Concurrency & In-Memory State Warning:
  • Registered IMemoryCache in Startup.cs with architectural documentation warning that in-memory cache is local to each container instance and does not persist across Cloud Run horizontal auto-scaling or scale-to-zero events. Cloud Memorystore (Redis) is recommended for distributed caching.

4. Containerization & Dockerfile Best Practices¶

• Multi-Stage Build:
  • Build stage: mcr.microsoft.com/dotnet/sdk:8.0.
  • Runtime stage: mcr.microsoft.com/dotnet/aspnet:8.0.
• Build Checks: Verified against Docker Build Checks with docker build --check . (0 errors, 0 warnings).
• Static Asset Serving: Bundler generates wwwroot/css/styles.css during publish, and favicon.ico is placed in wwwroot, serving all static assets with 200 OK.

Local Testing¶

Container Build¶

Build the container image using Docker:

docker build -t contosouniversity:latest .

To run Docker build checks without building:

docker build --check .

Direct Container Run¶

Run the container directly (ensure an accessible PostgreSQL instance is running):

docker run --rm \
  -p 8080:8080 \
  -e PORT=8080 \
  -e ConnectionStrings__SchoolContext="Host=host.docker.internal;Port=5432;Database=contosouniversity;Username=postgres;Password=postgres" \
  contosouniversity:latest

(Note: all docker run commands use the --rm flag to remove the container upon exit).

Docker Compose¶

Start the application and PostgreSQL database with build and detach options:

docker compose up --build --detach

Wait for the application to become ready:

for i in $(seq 60); do curl -sf -o /dev/null http://localhost:8080/ && break; sleep 2; done; docker compose logs --tail 50

Viewing Logs¶

View aggregate or service-specific logs:

# View combined logs
docker compose logs

# Tail last 50 lines of logs
docker compose logs --tail 50

# Follow live logs in real time
docker compose logs -f

# View application logs only
docker compose logs web

# View database logs only
docker compose logs db

Stopping and Cleaning Up¶

# Stop running containers
docker compose stop

# Remove stopped containers
docker compose rm --force

Endpoints¶

The application exposes the following HTTP endpoints:

Tested Endpoints Report¶

I tested all supported HTTP endpoints and main user flows against the running Docker Compose environment using curl.