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YASH MAISURIYA
YASH MAISURIYA

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🚀 Dockerizing and Setting Up CI/CD for a .NET API with GitLab

#docker #dotnet #gitlab #devops

In this guide, we'll walk through the steps to containerize a .NET API using Docker and set up a CI/CD pipeline with GitLab. This setup enables automatic building, testing, and deployment of your application, ensuring a smoother development lifecycle.

✅ Prerequisites
Before getting started, make sure you have the following:

  • A .NET API project (.NET 8 or compatible)
  • A GitLab account with a repository
  • Docker installed on your local machine

🐳 Dockerizing the .NET API

  • Create a Dockerfile in the root of your project directory. This file defines how to build your Docker image. 
# Base image for running the app FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base WORKDIR /app EXPOSE 80 EXPOSE 443 # Build image FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build WORKDIR /src COPY ["blog.backend.api/blog.backend.api.csproj", "blog.backend.api/"] RUN dotnet restore "blog.backend.api/blog.backend.api.csproj" COPY . . WORKDIR "/src/blog.backend.api" RUN dotnet build "blog.backend.api.csproj" -c Release -o /app/build # Publish image FROM build AS publish RUN dotnet publish "blog.backend.api.csproj" -c Release -o /app/publish /p:UseAppHost=false # Final image FROM base AS final WORKDIR /app COPY --from=publish /app/publish . ENTRYPOINT ["dotnet", "blog.backend.api.dll"]
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⚙️ Setting Up the GitLab CI/CD Pipeline

  • Create a .gitlab-ci.yml file at the root of your repository: 
image: docker:latest services: - docker:dind stages: - build - test - deploy variables: DOCKER_IMAGE: registry.gitlab.com/yash-project/blogApplicationAPI DOCKER_TAG: latest build: stage: build script: - docker build -f Dockerfile -t $DOCKER_IMAGE:$DOCKER_TAG . - echo "$CI_REGISTRY_PASSWORD" | docker login -u "$CI_REGISTRY_USER" --password-stdin $CI_REGISTRY - docker push $DOCKER_IMAGE:$DOCKER_TAG test: stage: test image: mcr.microsoft.com/dotnet/sdk:8.0 script: - dotnet test deploy: stage: deploy script: - echo "Deploying using Docker Compose..." - docker-compose up -d only: - main
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This pipeline includes three stages:

  • Build: Builds and pushes the Docker image to GitLab's container registry.
  • Test: Runs your unit/integration tests.
  • Deploy: Spins up the container using Docker Compose.

📦 Docker Compose Deployment
Create a docker-compose.yml file:

version: "3.9" services: blog-backend-api: image: registry.gitlab.com/yash-project/blogApplicationAPI:latest ports: - "80:80"
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  • This simple setup pulls the latest image and runs your API on port 80.

🎯 Conclusion
By combining Docker with GitLab CI/CD, you now have a robust and automated workflow for building, testing, and deploying your .NET API. This approach streamlines development and ensures consistency across environments.

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