.NET

Detection

migetpacks detects a .NET application when any of the following are present:

*.sln or *.slnx (solution files, root level)
global.json (root level)
*.csproj, *.fsproj, or *.vbproj (project files, up to 2 levels deep)

Version Detection

.NET SDK version is resolved in the following priority order:

Source	Example
`global.json` (`sdk.version`)	`{"sdk": {"version": "8.0.100"}}`
`*.csproj` (`TargetFramework`)	`<TargetFramework>net8.0</TargetFramework>`
Default	`8.0`

The TargetFramework value has the net prefix stripped (e.g., net8.0 becomes 8.0).

Build Process

migetpacks generates a multi-stage Dockerfile using the official .NET SDK and ASP.NET runtime images:

# Build stage
FROM mcr.microsoft.com/dotnet/sdk:8.0 AS builder
WORKDIR /build

# .NET build optimizations
ENV NUGET_XMLDOC_MODE=skip
ENV DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
ENV DOTNET_CLI_TELEMETRY_OPTOUT=1
ENV DOTNET_NOLOGO=1

# Copy source code
COPY . .

# Restore, build, and publish
RUN dotnet restore \
    && dotnet publish --configuration Release --no-restore -p:PublishDir=bin/publish

# Runtime stage
FROM mcr.microsoft.com/dotnet/aspnet:8.0
WORKDIR /app
COPY --from=builder --chown=1000:1000 /build /app

Source Code Cleanup

Since .NET is a compiled language, source code is completely removed from the runtime image after publishing:

Removed	Reason
`.cs`, `.fs`, `*.vb`	Source files (compiled to DLLs)
`.csproj`, `.fsproj`, `*.vbproj`	Project files
`.sln`, `.slnx`	Solution files
`obj/`	Intermediate build files
`bin/Release/net*/`, `bin/Debug/`	Non-publish build output

Only the bin/publish/ directory contents are kept in the final image.

.NET Tool Restore

If a .config/dotnet-tools.json is present, dotnet tool restore is run before the build to install any required .NET CLI tools.

Run Command

The default run command for .NET applications:

dotnet MyApp.dll

migetpacks detects the main DLL from the publish output. Override with RUN_COMMAND or a Procfile:

web: dotnet MyApp.dll --urls http://0.0.0.0:5000

Runtime Configuration

The following environment variables are set for production:

Variable	Value
`ASPNETCORE_ENVIRONMENT`	`Production`
`DOTNET_RUNNING_IN_CONTAINER`	`true`
`DOTNET_SYSTEM_GLOBALIZATION_INVARIANT`	`1`
`DOTNET_CLI_TELEMETRY_OPTOUT`	`1`
`ASPNETCORE_HTTP_PORTS`	`5000`

Caching

Layer Caching

The .NET build uses NuGet cache mounts for dependency caching:

Scenario	Dependency Restore
First build	Runs
Source code change only	NuGet packages cached via mount
Project file change	Runs restore

BUILD_CACHE_DIR

When BUILD_CACHE_DIR is set, NuGet packages are cached via BuildKit mount at:

Cache Path	Contents
NuGet packages mount	`~/.nuget/packages`

DHI Support

Docker Hardened Images are supported for .NET builds.

Stage	Image
Build	`dhi.io/dotnet:{version}-sdk`
Runtime	`dhi.io/aspnetcore:{version}`

DHI Notes

Build SDK images include the full .NET SDK for compilation.
Runtime images are based on ASP.NET Core distroless images (no shell, no apt-get).
The nonroot user is used instead of the miget user.
Suitable for web APIs and ASP.NET Core applications.

Example with DHI

docker run --rm \
  -v /path/to/dotnet-app:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-dotnet-app:latest \
  -e USE_DHI=true \
  miget/migetpacks:latest

Example

docker run --rm \
  -v /path/to/dotnet-app:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-dotnet-app:latest \
  miget/migetpacks:latest

Monorepo with PROJECT_PATH

docker run --rm \
  -v /path/to/monorepo:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-api:latest \
  -e PROJECT_PATH=src/MyApi \
  miget/migetpacks:latest

With custom build command

docker run --rm \
  -v /path/to/dotnet-app:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-dotnet-app:latest \
  -e BUILD_COMMAND="dotnet publish -c Release -o /build/out" \
  miget/migetpacks:latest

Getting Started

Guides

Configuration

Languages

Deploying

Reference

Detection

Version Detection

Build Process

Source Code Cleanup

.NET Tool Restore

Run Command

Runtime Configuration

Caching

Layer Caching

BUILD_CACHE_DIR

DHI Support

DHI Notes

Example with DHI

Example

Monorepo with PROJECT_PATH

With custom build command

​Detection

​Version Detection

​Build Process

​Source Code Cleanup

​.NET Tool Restore

​Run Command

​Runtime Configuration

​Caching

​Layer Caching

​BUILD_CACHE_DIR

​DHI Support

​DHI Notes

​Example with DHI

​Example

​Monorepo with PROJECT_PATH

​With custom build command

Detection

Version Detection

Build Process

Source Code Cleanup

.NET Tool Restore

Run Command

Runtime Configuration

Caching

Layer Caching

BUILD_CACHE_DIR

DHI Support

DHI Notes

Example with DHI

Example

Monorepo with PROJECT_PATH

With custom build command