buildah-build/README.md

# buildah-build
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Buildah is a GitHub Action for building Docker and Kubernetes-compatible images quickly and easily.

Buildah only works on Linux. GitHub's [Ubuntu Environments](https://github.com/actions/virtual-environments#available-environments) (`ubuntu-18.04` and newer) come with buildah installed. If you are not using these environments, or if you want to use a different version, you must first [install buildah](https://github.com/containers/buildah/blob/master/install.md).

After building your image, use [push-to-registry](https://github.com/redhat-actions/push-to-registry) to push the image and make it pullable.

## Action Inputs

### Inputs for build from dockerfile

| Input Name | Description | Default |
| ---------- | ----------- | ------- |
| build-args | Build arguments to pass to the Docker build using `--build-arg`, if using a Dockerfile that requires ARGs. Use the form `arg_name=arg_value`, and separate arguments with newlines. | None
| context | Path to directory to use as the build context. | `.`
| dockerfiles | The list of Dockerfile paths to perform a build using docker instructions. This is a multiline input to allow multiple Dockerfiles. | **Must be provided**
| image | Name to give to the output image. | **Must be provided**
| oci | Build the image using the OCI format, instead of the Docker format. By default, this is `false`, because images built using the OCI format have issues when published to Dockerhub. | `false`
| tags | The tags of the image to build. For multiple tags, separate by a space. For example, `latest ${{ github.sha }}` | `latest`

### Inputs for build without dockerfile

| Input Name | Description | Default |
| ---------- | ----------- | ------- |
| base-image | The base image to use for the container. | **Must be provided**
| content | Paths to files or directories to copy inside the container to create the file image. This is a multiline input to allow you to copy multiple files/directories.| None
| context | Path to directory to use as the build context. | `.`
| entrypoint | The entry point to set for the container. This is a multiline input; split arguments across lines. | None
| envs | The environment variables to be set when running the container. This is a multiline input to add multiple environment variables. | None
| image | Name to give to the output image. | **Must be provided**
| oci | Build the image using the OCI format, instead of the Docker format. By default, this is `false`, because images built using the OCI format have issues when published to Dockerhub. | `false`
| port | The port to expose when running the container. | None
| tags | The tags of the image to build. For multiple tags, separate by a space. For example, `latest ${{ github.sha }}` | `latest`
| workdir | The working directory to use within the container. | None

## Action Outputs

`image`: The name of the built image.<br>
For example, `spring-image`.

`tags`: A list of the tags that were created, separated by spaces.<br>
For example, `latest ${{ github.sha }}`.

## Build Types

You can configure the `buildah` action to build your image using one or more Dockerfiles, or none at all.

### Building using Dockerfiles

If you have been building your images with an existing Dockerfile, `buildah` can reuse your Dockerfile.

In this case the inputs needed are `image` and `dockerfiles`. `tag` is also recommended. If your Dockerfile requires ARGs, these can be passed using `build-arg`.

```yaml
name: Build Image using Dockerfile
on: [push]

jobs:
  build:
    name: Build image
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2

    - name: Buildah Action
      uses: redhat-actions/buildah-build@v2
      with:
        image: my-new-image
        tags: v1 ${{ github.sha }}
        dockerfiles: |
          ./Dockerfile
        build-args: |
          some_arg=some_value
```

### Building without a Dockerfile

Building without a Dockerfile requires additional inputs, that would normally be specified in the Dockerfile.

Do not set `dockerfiles` if you are doing a build from scratch. Otherwise those Dockerfiles will be used, and the inputs below will be ignored.

- An output `image` name and usually a `tag`.
- `base-image`
  - In a Dockerfile, this would be the `FROM` directive.
- `content` to copy into the new image
  - In a Dockerfile, this would be `COPY` directives.
- `entrypoint` so the container knows what command to run.
  - In a Dockerfile, this would be the `ENTRYPOINT`.
- All other optional configuration inputs, such as `port`, `envs`, and `workdir`.

Example of building a Spring Boot Java app image:
```yaml
name: Build Image
on: [push]

jobs:
  build-image:
    name: Build image without Dockerfile
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2

    - run: mvn package

    - name: Build Image
      uses: redhat-actions/buildah-build@v2
      with:
        base-image: docker.io/fabric8/java-alpine-openjdk11-jre
        image: my-new-image
        tags: v1
        content: |
          target/spring-petclinic-2.3.0.BUILD-SNAPSHOT.jar
        entrypoint: java -jar spring-petclinic-2.3.0.BUILD-SNAPSHOT.jar
        port: 8080
```

## Using private images
If your build requires a private image, you have to `docker login` in a step before running this action.

For example:
```yaml
- name: Log in to Red Hat Registry
  run: echo "${{ secrets.REGISTRY_REDHAT_IO_PASSWORD }}" | docker login registry.redhat.io -u "${{ secrets.REGISTRY_REDHAT_IO_USER }}" --password-stdin
```