michelav/dotnetcore-docker-mods

A set of useful stuff to develop .NET Core apps in linux with containers

About this Repo

Recently, I was trying to develop .NET Core applications in Linux environment without installing its runtime and SDK. I've used the guidelines in the official repository. It works good, but there is a subtle problem when you need to save directory or files generated from container into the host: file permissions.

.NET Core official images run as root user so all generated files belong to "root:root". Therefore, when you try to modify any of the created files in the host you get a "permission denied" message (see issue 271). In the case you want to have full control of created files in the host you must run the container with the same user you want to be the real owner.

One may find --user option in docker run command a valid choice to solve this problem, but if the user entered isn't registered in the container, it won't work. Check below:

the images described in this repository assure the user and group exist in the .NET core SDK container.

Previous readings and requirements

You should read the guidelines in the repository for .NET Core Docker images. Particularly, you should understand the development model described in Develop .NET Core Applications in a Container.

Image List

Usage

The Dockerfiles in this repo relies on build-time variables as parameters to determine the user in the container.

You should build a custom image passing the "arg-variables" URS, UID, GRP and GID.

docker build --build-arg USR=$(id -nu) --build-arg UID=$(id -u) --build-arg GRP=$(id -ng) --build-arg GID=$(id -g) -t my-dotnetcore-sdk -f Dockerfile-dotnetcore-sdk .

Thereafter, you can use the new image just like the following example:

docker run --rm -v ~/devel/apis:/home/$(id -nu) my-dotnetcore-sdk dotnet new webapi -o MyApi