ASP.Net Core HelloWorld with docker support

Based on the following tutorial: https://stormpath.com/blog/tutorial-deploy-asp-net-core-on-linux-with-docker

Prerequisite

Microsoft Core SDK https://go.microsoft.com/fwlink/?LinkID=835014

Docker https://www.docker.com/

Step 1 - Create dotnet core project

mkdir AspNetCoreHelloWorld
cd AspNetCoreHelloWorld
dotnet new web

Make sure everything is working!

dotnet restore
dotnet run

Step 2 - Build dockerfile for ASP.NET Core

FROM microsoft/dotnet:latest
COPY . /app
WORKDIR /app
 
RUN ["dotnet", "restore"]
RUN ["dotnet", "build"]
 
EXPOSE 5000/tcp
ENV ASPNETCORE_URLS http://*:5000
 
ENTRYPOINT ["dotnet", "run"]

Here’s what each of these instructions does:

FROM tells Docker that you want to base your image on the existing image called microsoft/dotnet:latest. This image already contains all the dependencies for running .NET Core on Linux, so you don’t have to worry about setting those up.

COPY and WORKDIR copy the current directory’s contents into a new directory inside the container called /app, and set that to the the working directory for the subsequent instructions.

RUN executes dotnet restore and dotnet build, which restores the packages needed to run the ASP.NET Core application and compiles the project.

EXPOSE tells Docker to expose port 5000 (the default port for ASP.NET) on the container.

ENV sets the environment variable ASPNETCORE_URLS in the container. This will ensure that ASP.NET Core binds to the correct port and address.

ENTRYPOINT specifies the command to execute when the container starts up. In this case, it’s dotnet run.

Step 3 - Creating the Docker image

docker build -t mydemos:aspnetcorehelloworld .

Do not forget the dot at the end!

Step 4 - Run the docker image

docker run -d -p 8080:5000 -t mydemos:aspnetcorehelloworld

The -d flag tells Docker to run the container in detached mode (in the background). The -p flag will map port 8080 on the host machine to port 5000 inside the container. Finally, the -t flag is used to specify which image to run.

That’s it! You should see your container running when you check docker ps. Open up a web browser and navigate to http://localhost:8080. You should see the welcome page: