Images

Overview

When you want to conditionally deploy a container or Acorn based on the user's preference, you can use the images block in your Acornfile to ensure the images are included in the final image.

To understand when to use images, review the following example Acornfile:

args: enableRedis: false

if args.enableRedis {
    containers: redis: {
        image: "redis"
    }
}

containers: app: {
    image: "myapp"
    if args.enableRedis {
        dependsOn: ["redis"]
    }
}

In this simple Acornfile the redis container is only deployed if the user provides the --enableRedis argument. If the user does not provide the argument, the redis container is not included in the deployment. The problem that arises is during the build process, Acorn will not see the redis container and will not include it in the final image. This will cause the app container to fail to start when deployed with an image not found error.

To address this, you can use the images block to ensure the redis container is included in the final image:

args: enableRedis: false

if args.enableRedis {
    containers: redis: {
        image: images.redisimage.image
    }
}

containers: app: {
    image: "nginx"
    if args.enableRedis {
        dependsOn: ["redis"]
    }
}

images: redisimage: image: "index.docker.io/redis"

Now when the end user deploy's the resulting Acorn they can successfully enable the redis container by providing the --enableRedis argument.

Usage

The images block is a map of images and how to reference them from a registry, build from a Dockerfile, or build an Acornfile.

Here is an example of each.

...
images: {
    // Can be a container or Acorn image in a registry
    fromimage: image: "index.docker.io/redis"
    // The same fields from a container build can be used here.
    fromdockerfile: containerBuild: {
        context: "."
    }
    // Same fields as an Acornfile build can be used here.
    fromacornbuild: acornBuild: {
        context: "."
        acornfile: "Acornfile"
    }
}

containers: {
    "registry-image": {
        image: images.fromimage.image
    }
    "docker-build": {
        build: images.fromdockerfile.containerBuild
    }
}

acorns: {
    "from-registry": {
        image: images.fromimage.image
    }
    "from-acorn-build": {
        build: images.fromacornbuild.acornBuild
    }
}