Build a container project from the command line
If you want to build a container project with a Dockerfile outside of Visual Studio, you can use docker build, MSBuild, dotnet build, or dotnet publish to build from the command line.
If you're using the .NET SDK build type, you don't have a Dockerfile, so you can't use docker build; instead, use MSBuild, dotnet build or dotnet publish to build on the command line.
Use Docker build
To build a containerized solution from the command line, you can usually use the command docker build <context> for each project in the solution. You provide the build context argument. The build context for a Dockerfile is the folder on the local machine that's used as the working folder to generate the image. For example, it's the folder that you copy files from when you copy to the container. In .NET Core projects, the default is to use the folder that contains the solution file (.sln). Expressed as a relative path, this argument is typically ".." for a Dockerfile in a project folder, and the solution file in its parent folder. For .NET Framework projects, the default build context is the project folder, not the solution folder.
docker build -f Dockerfile ..
You can set the build context in the project file by setting the DockerfileContext property. For example,
<PropertyGroup>
<DockerfileContext>contextfolder</DockerfileContext>
</PropertyGroup>
Relative paths in the Dockerfile are relative to the build context, so if you change the context, be sure to update the relative paths accordingly.
With Visual Studio 17.11 and later, when you add Docker support to a project, you can specify a folder for the build context. If you want to change the build context, you could delete the Dockerfile (if it doesn't have other changes you want to keep), and rerun Add Docker support, this time specifying the new build context. The new Dockerfile will have relative paths updated to correspond to the new build context.
Use MSBuild
Note
This section describes how you can customize your Docker containers when you choose the Dockerfile container build type. If you are using the .NET SDK build type, the customization options are different, and the information in this article isn't applicable. Instead, see Containerize a .NET app with dotnet publish.
Dockerfiles created by Visual Studio for .NET Framework projects (and for .NET Core projects created with versions of Visual Studio prior to Visual Studio 2017 Update 4) aren't multistage Dockerfiles. The steps in these Dockerfiles don't compile your code. Instead, when Visual Studio builds a .NET Framework Dockerfile, it first compiles your project using MSBuild. When that succeeds, Visual Studio then builds the Dockerfile, which simply copies the build output from MSBuild into the resulting Docker image. Because the steps to compile your code aren't included in the Dockerfile, you can't build .NET Framework Dockerfiles using docker build from the command line. You should use MSBuild to build these projects.
To build an image for single Docker container project, you can use MSBuild with the /t:ContainerBuild command option. This command tells MSBuild to build the target ContainerBuild rather than the default target Build. For example:
MSBuild MyProject.csproj /t:ContainerBuild /p:Configuration=Release
You see output similar to what you see in the Output window when you build your solution from the Visual Studio IDE. Always use /p:Configuration=Release, since in cases where Visual Studio uses the multistage build optimization, results when building the Debug configuration might not be as expected. See Customize container images for debugging.
If you're using a Docker Compose project, use this command to build images:
msbuild /p:SolutionPath=<solution-name>.sln /p:Configuration=Release docker-compose.dcproj
To view the MSBuild logs, see Obtaining build logs with MSBuild.