Dramatically shrinking .net core 3.1 docker image publishing size

Dockerfile

# Officia microsoft .NET SDK image
FROM mcr.microsoft.com/dotnet/core/sdk:latest AS api-build

# Set directory for build
WORKDIR /app

# Copy anything from where docker would be builded
COPY ./. ./

# Reice packages, Build and shrink as an standalone exutable file
RUN dotnet publish -c Release -r linux-musl-x64 /p:PublishSingleFile=true /p:PulishTrimmed=true -o out

# Very small linux as an base for service
FROM alpine:latest AS runtime

# Set directory to run from
WORKDIR /app/

# Copy .NET exutable to small linux image
COPY --from=api-build /app/out/. .

# Install libraries to .NET exutable work
RUN apk update && apk add --no-cache libstdc++ libgcc gcompat musl libc6-compat libintl icu-dev icu

# Allow to redirect and get work .NET web service from any host
# But needs to open(dispose) ports by run docker
ENV ASPNETCORE_URLS=http://+:80

# Doesn't work but defined :)
# Right way example: docker run -t service -p80:80 .
EXPOSE 80

# Run service as standalone exutable by default
# But you can easily override antry point
# Example: docker build -t project-service . && docker run project-service
ENTRYPOINT ["/app/ProjectService"]