Build arguments

Not all information can or should be hardcoded in the configuration file. Build arguments let you pass information to builder processes at build time which can reduce redundancy in your configuration and make the build more flexible. Note that build arguments become environment variables in the resulting image configuration and should not be used to store sensitive values.

Using an argument to generalize a builder/variant

Given examples/web-app as a working directory

And this "blubber.yaml"

version: v4
variants:
  make:
    base: debian:stable
    arguments:
      MAKE_TARGET: foo
    apt:
      packages: [make]
    builders:
      - custom:
          requirements: [Makefile]
          command: "make ${MAKE_TARGET}"

When you build the "make" variant with the following build arguments

MAKE_TARGET	bar

Then the image will have the following files in the default working directory

bar