Building specific dockerfile

To build a docker file, you would normally navigate to a folder where it’s located and run:

docker build .

That will assume, that a dockerfile is located in a folder from where you run the command. A dot is a context in which the docker build will run. Sometimes a dockerfile is nested within subfolders and it’s easier to specify a dockerfile and keep the “wider context”. What I mean by that?

For example, let’s assume we have a folder structure:

devops
  |->azure_pipelines.yaml
docs
  |->readme.md
src
  |->MyLibrary
      |->Class.cs
  |->UnitTests
      |->Class1Tests.cs 
  |->Service
      |->Dockerfile 

I want to run the docker build from the top folder to have a better control over the context. To instruct the docker build to build from specified dockerfile you can write this instead:

docker build -f src/Service/Dockerfile .

I like this approach, since I can have the whole scope and context in actions within a Dockerfile.