ChdirWithTracking performs a chdir and return the tracking object.

KeyValueArgumentObfuscator returns a function to scan the argument list and replace the secret argument value with the obfuscation string.

NewDockerBuild creates a build target with specified docker file and build parameters.

NewDockerSource creates a new passthrough source.

NewDockerUsernamePassword creates a authentication object with username and password.

PopulateDigests populates digests on dependencies.

DirectoryTracker tracks switching of directories.

DockerSource is a source we can pass directly into docker.