A target in a Bake file represents a build invocation. It holds all the information you would normally pass to a docker build command using flags.

target "webapp" {
  dockerfile = "webapp.Dockerfile"
  tags = ["docker.io/username/webapp:latest"]
  context = "https://github.com/username/webapp"
}

To build a target with Bake, pass name of the target to the bake command.

$ docker buildx bake webapp

You can build multiple targets at once by passing multiple target names to the bake command.

$ docker buildx bake webapp api tests

Default target#

If you don't specify a target when running docker buildx bake, Bake will build the target named default.

target "default" {
  dockerfile = "webapp.Dockerfile"
  tags = ["docker.io/username/webapp:latest"]
  context = "https://github.com/username/webapp"
}

To build this target, run docker buildx bake without any arguments:

$ docker buildx bake

Target properties#

The properties you can set for a target closely resemble the CLI flags for docker build, with a few additional properties that are specific to Bake.

For all the properties you can set for a target, see the Bake reference.

Grouping targets#

You can group targets together using the group block. This is useful when you want to build multiple targets at once.

group "all" {
  targets = ["webapp", "api", "tests"]
}

target "webapp" {
  dockerfile = "webapp.Dockerfile"
  tags = ["docker.io/username/webapp:latest"]
  context = "https://github.com/username/webapp"
}

target "api" {
  dockerfile = "api.Dockerfile"
  tags = ["docker.io/username/api:latest"]
  context = "https://github.com/username/api"
}

target "tests" {
  dockerfile = "tests.Dockerfile"
  contexts = {
    webapp = "target:webapp",
    api = "target:api",
  }
  output = ["type=local,dest=build/tests"]
  context = "."
}

To build all the targets in a group, pass the name of the group to the bake command.

$ docker buildx bake all

Additional resources#

Refer to the following pages to learn more about Bake's features:

• Learn how to use variables in Bake to make your build configuration more flexible.
• Learn how you can use matrices to build multiple images with different configurations in Matrices.
• Head to the Bake file reference to learn about all the properties you can set in a Bake file, and its syntax.