buildx/docs/reference/buildx_bake.md

buildx bake

Usage:  docker buildx bake [OPTIONS] [TARGET...]

Build from a file

Aliases:
  bake, f

Options:
      --builder string     Override the configured builder instance
  -f, --file stringArray   Build definition file
      --load               Shorthand for --set=*.output=type=docker
      --no-cache           Do not use cache when building the image
      --print              Print the options without building
      --progress string    Set type of progress output (auto, plain, tty). Use plain to show container output (default "auto")
      --pull               Always attempt to pull a newer version of the image
      --push               Shorthand for --set=*.output=type=registry
      --set stringArray    Override target value (eg: targetpattern.key=value)

Description

Bake is a high-level build command. Each specified target will run in parallel as part of the build.

Examples

Specify a build definition file (-f, --file)

By default, buildx bake looks for build definition files in the current directory, the following are parsed:

• docker-compose.yml
• docker-compose.yaml
• docker-bake.json
• docker-bake.override.json
• docker-bake.hcl
• docker-bake.override.hcl

Use the -f / --file option to specify the build definition file to use. The file can be a Docker Compose, JSON or HCL file. If multiple files are specified they are all read and configurations are combined.

The following example uses a Docker Compose file named docker-compose.dev.yaml as build definition file, and builds all targets in the file:

$ docker buildx bake -f docker-compose.dev.yaml

[+] Building 66.3s (30/30) FINISHED
 => [frontend internal] load build definition from Dockerfile  0.1s
 => => transferring dockerfile: 36B                            0.0s
 => [backend internal] load build definition from Dockerfile   0.2s
 => => transferring dockerfile: 3.73kB                         0.0s
 => [database internal] load build definition from Dockerfile  0.1s
 => => transferring dockerfile: 5.77kB                         0.0s
 ...

Pass the names of the targets to build, to build only specific target(s). The following example builds the backend and database targets that are defined in the docker-compose.dev.yaml file, skipping the build for the frontend target:

$ docker buildx bake -f docker-compose.dev.yaml backend database

[+] Building 2.4s (13/13) FINISHED
 => [backend internal] load build definition from Dockerfile  0.1s
 => => transferring dockerfile: 81B                           0.0s
 => [database internal] load build definition from Dockerfile 0.2s
 => => transferring dockerfile: 36B                           0.0s
 => [backend internal] load .dockerignore                     0.3s
 ...

Do not use cache when building the image (--no-cache)

Same as build --no-cache. Do not use cache when building the image.

Print the options without building (--print)

Prints the resulting options of the targets desired to be built, in a JSON format, without starting a build.

$ docker buildx bake -f docker-bake.hcl --print db
{
   "target": {
      "db": {
         "context": "./",
         "dockerfile": "Dockerfile",
         "tags": [
            "docker.io/tiborvass/db"
         ]
      }
   }
}

Set type of progress output (--progress)

Same as build --progress. Set type of progress output (auto, plain, tty). Use plain to show container output (default "auto").

The following example uses plain output during the build:

$ docker buildx bake --progress=plain

#2 [backend internal] load build definition from Dockerfile.test
#2 sha256:de70cb0bb6ed8044f7b9b1b53b67f624e2ccfb93d96bb48b70c1fba562489618
#2 ...

#1 [database internal] load build definition from Dockerfile.test
#1 sha256:453cb50abd941762900a1212657a35fc4aad107f5d180b0ee9d93d6b74481bce
#1 transferring dockerfile: 36B done
#1 DONE 0.1s
...

Always attempt to pull a newer version of the image (--pull)

Same as build --pull.

Override target configurations from command line (--set)

--set targetpattern.key[.subkey]=value

Override target configurations from command line. The pattern matching syntax is defined in https://golang.org/pkg/path/#Match.

Example:

docker buildx bake --set target.args.mybuildarg=value
docker buildx bake --set target.platform=linux/arm64
docker buildx bake --set foo*.args.mybuildarg=value # overrides build arg for all targets starting with 'foo'
docker buildx bake --set *.platform=linux/arm64     # overrides platform for all targets
docker buildx bake --set foo*.no-cache              # bypass caching only for targets starting with 'foo'

Complete list of overridable fields: args, cache-from, cache-to, context, dockerfile, labels, no-cache, output, platform, pull, secrets, ssh, tags, target

File definition

In addition to compose files, bake supports a JSON and an equivalent HCL file format for defining build groups and targets.

A target reflects a single docker build invocation with the same options that you would specify for docker build. A group is a grouping of targets.

Multiple files can include the same target and final build options will be determined by merging them together.

In the case of compose files, each service corresponds to a target.

A group can specify its list of targets with the targets option. A target can inherit build options by setting the inherits option to the list of targets or groups to inherit from.

Note: Design of bake command is work in progress, the user experience may change based on feedback.

Example HCL definition:

group "default" {
    targets = ["db", "webapp-dev"]
}

target "webapp-dev" {
    dockerfile = "Dockerfile.webapp"
    tags = ["docker.io/username/webapp"]
}

target "webapp-release" {
    inherits = ["webapp-dev"]
    platforms = ["linux/amd64", "linux/arm64"]
}

target "db" {
    dockerfile = "Dockerfile.db"
    tags = ["docker.io/username/db"]
}

Complete list of valid target fields: args, cache-from, cache-to, context, dockerfile, inherits, labels, no-cache, output, platform, pull, secrets, ssh, tags, target

HCL variables and functions

Similar to how Terraform provides a way to define variables, the HCL file format also supports variable block definitions. These can be used to define variables with values provided by the current environment, or a default value when unset.

Example of using interpolation to tag an image with the git sha:

$ cat <<'EOF' > docker-bake.hcl
variable "TAG" {
    default = "latest"
}

group "default" {
    targets = ["webapp"]
}

target "webapp" {
    tags = ["docker.io/username/webapp:${TAG}"]
}
EOF

$ docker buildx bake --print webapp
{
   "target": {
      "webapp": {
         "context": ".",
         "dockerfile": "Dockerfile",
         "tags": [
            "docker.io/username/webapp:latest"
         ]
      }
   }
}

$ TAG=$(git rev-parse --short HEAD) docker buildx bake --print webapp
{
   "target": {
      "webapp": {
         "context": ".",
         "dockerfile": "Dockerfile",
         "tags": [
            "docker.io/username/webapp:985e9e9"
         ]
      }
   }
}

A set of generally useful functions provided by go-cty are available for use in HCL files. In addition, user defined functions are also supported.

Example of using the add function:

$ cat <<'EOF' > docker-bake.hcl
variable "TAG" {
    default = "latest"
}

group "default" {
    targets = ["webapp"]
}

target "webapp" {
    args = {
        buildno = "${add(123, 1)}"
    }
}
EOF

$ docker buildx bake --print webapp
{
   "target": {
      "webapp": {
         "context": ".",
         "dockerfile": "Dockerfile",
         "args": {
            "buildno": "124"
         }
      }
   }
}

Example of defining an increment function:

$ cat <<'EOF' > docker-bake.hcl
function "increment" {
    params = [number]
    result = number + 1
}

group "default" {
    targets = ["webapp"]
}

target "webapp" {
    args = {
        buildno = "${increment(123)}"
    }
}
EOF

$ docker buildx bake --print webapp
{
   "target": {
      "webapp": {
         "context": ".",
         "dockerfile": "Dockerfile",
         "args": {
            "buildno": "124"
         }
      }
   }
}

Example of only adding tags if a variable is not empty using an notequal function:

$ cat <<'EOF' > docker-bake.hcl
variable "TAG" {default="" }

group "default" {
    targets = [
        "webapp",
    ]
}

target "webapp" {
    context="."
    dockerfile="Dockerfile"
    tags = [
        "my-image:latest",
        notequal("",TAG) ? "my-image:${TAG}": "",
    ]
}
EOF

$ docker buildx bake --print webapp
{
   "target": {
      "webapp": {
         "context": ".",
         "dockerfile": "Dockerfile",
         "tags": [
            "my-image:latest"
         ]
      }
   }
}