Containerize application with Docker

[nanotaboada]

Description

We need to containerize the Dotnet.Samples.AspNetCore.WebApi application to support development and deployment scenarios with Docker. The container should run as a non-root user.

Suggested Approach

• Create a Dockerfile using a multi-stage build:
  • Build stage: use mcr.microsoft.com/dotnet/sdk:8.0 to restore, build, and publish the app.
  • Runtime stage: use mcr.microsoft.com/dotnet/aspnet:8.0 to run the published app in a minimal environment.- Expose port 9000.
• Use environment variables to configure the app (e.g. ASPNETCORE_URLS=http://+:9000).
• Use a non-root user (aspnetcore) in the final image for hardening.

Proposed Implemenation

Dockerfile

# - Stage 1 --------------------------------------------------------------------
    FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
    WORKDIR /src

    # Copy and restore dependencies
    COPY src/Dotnet.Samples.AspNetCore.WebApi/*.csproj ./Dotnet.Samples.AspNetCore.WebApi/
    RUN dotnet restore ./Dotnet.Samples.AspNetCore.WebApi

    # Copy source and publish
    COPY src/Dotnet.Samples.AspNetCore.WebApi ./Dotnet.Samples.AspNetCore.WebApi
    WORKDIR /src/Dotnet.Samples.AspNetCore.WebApi
    RUN dotnet publish -c Release -o /app/publish

# - Stage 2 --------------------------------------------------------------------
    FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS runtime
    WORKDIR /app

    # Copy published output
    # Note: This includes the SQLite database because it's marked as <Content> with
    # <CopyToOutputDirectory> in the .csproj file. No need to copy it manually.
    COPY --from=build /app/publish .

    # Add non-root user (aspnetcore) and switch to it
    RUN adduser --disabled-password --gecos '' aspnetcore \
        && chown -R aspnetcore:aspnetcore /app
    USER aspnetcore

    # Set environment variables
    ENV ASPNETCORE_URLS=https://+:9000
    ENV ASPNETCORE_ENVIRONMENT=Production

    # Default entrypoint
    ENTRYPOINT ["dotnet", "Dotnet.Samples.AspNetCore.WebApi.dll"]

docker-compose.override.yml

version: "3.9"
services:
  webapi:
    environment:
      ASPNETCORE_ENVIRONMENT: Development
      ASPNETCORE_URLS: https://+:9000
    volumes:
      - ./https:/https:ro
      - ./src/Dotnet.Samples.AspNetCore.WebApi/Data:/app/Data:ro

Acceptance Criteria

• Docker image builds successfully using docker build -t dotnet-samples-aspnetcore-webapi ..
• Docker container runs successfully using docker run -p 9000:9000 dotnet-samples-aspnetcore-webapi:latest
• The app listens on http://localhost:9000.
• Runs as non-root (aspnetcore) in container.