| image | The target image `repo:tag` name. The tag is optional, and if given, the resulting image will be additionally tagged with that tag. The image will always be tagged with the generated tag, regardless of the given tag. | yes | — |
| context | A directory to use as the Docker build context. The Dockerfile must also be located somewhere within this directory. The path can be relative to the current working directory, typically the root of the repository. | yes | — |
| dockerfile | The Dockerfile to use for the build. The path can be relative to the current working directory, typically the root of the repository. | no | Dockerfile |
| base-image | The optional base image `repo:tag` name. If given, this will be supplied as a Docker build argument BASE_IMAGE. It will also participate in tag generation. | no | "" |
| build-args | The optional arguments to supply to the Docker build. They will also participate in tag generation. (All build arguments will actually be appended to the build context in a special file `.buildargs`.) | no | "" |
| secrets | The secrets to supply to the Docker build. They will not participate in tag generation. | no | "" |
| sub-build-args | Optional secondary build arguments to supply to the Docker build. They will not participate in tag generation. (Don't use this unless you know what you're doing.) | no | "" |
| sub-contexts | Optional secondary Docker build context. Each directory will get injected into the main build context under the 'subcontext' directory, but these directories will not participate in tag generation. (Don't use this unless you know what you're doing.) | no | "" |
| only-pull | Only attempt to pull the image. Do not build the image. | no | false |
| skip-pull | Check if the image is available on the registry as usual, but if it is available, don't actually pull the image. | no | false |
| push | Push the container after building. | no | false |
| registry-user | The user to use in authenticating to the Docker registry. | no | ${{ github.actor }} |
| registry-pass | The password (or token) to use in authenticating to the Docker registry. | no | "" |
| no-cache | Force a rebuild of the image, and do not use cache. | no | false |
| name-only | Only generate the tag, and print the resulting image name. Do not actually build the image. | no | false |