sample of bake config

bake.hcl

group "default" {
  targets = ["app", "editor"]
}

variable "TAG" {
  default = "test"
}

variable "APP_VERSION" {
  default = "2"
}

variable "GITHUB_ACTIONS" {
  default = ""
}

variable "REGISTRY" {
  default = "my.registry"
}

function "tags" {
  params = [name]
  result = "${REGISTRY}/${name}:${TAG}"
}

function "buildtag" {
  params = [name]
  result = "my.registry/${name}:${TAG}-build"
}

function "ghaexport" {
  params = [name]
  result = notequal("", GITHUB_ACTIONS) ? "${regex_replace("type=gha,mode=max,scope=buildkit${name}", "\\.", "_")}" : ""
}

function "ghaimport" {
  params = [name]
  result = notequal("", GITHUB_ACTIONS) ? "${regex_replace("type=gha,scope=buildkit${name}", "\\.", "_")}" : ""
}

target "_base" {
  context = "./app"
  contexts = {
    dep1-src = "./dep1"
    dep2-src = "./dep2"
  }
  cache-from = [
    "type=registry,ref=my.registry/dep1:latest-build",
  ]
  cache-to = [
    "type=registry,ref=my.registry/build-dep1:latest-build,mode=max",
  ]
  target = "dep1"
  platforms = ["linux/amd64"]
}

target "app" {
  name = versions.name
  inherits = ["_base74"]

  matrix = {
    versions = [
      {
        version = "1"
        name = "app1"
      },
      {
        version = "2"
        name = "app2"
      },
      {
        version = "3"
        name = "app3"
      },
      {
        version = "4"
        name = "app4"
      },
      {
        version = "5"
        name = "app5"
      }
    ]
  }

  args = {
    APP_VERSION = versions.version
  }

  cache-from = [
    "type=registry,ref=my.registry/${versions.name}:latest-build",
    "type=registry,ref=${buildtag(versions.name)}",
  ]

  tags = [tags(versions.name)]
  cache-to = [
    "type=registry,ref=${buildtag(versions.name)},mode=max",
  ]
  target = "app"
}

target "editor" {
  name = "editor-${versions.name}"

  matrix = {
    versions = [
      {
        version = "1"
        name = "editor1"
      },
      {
        version = "2"
        name = "editor2"
      },
      {
        version = "3"
        name = "editor3"
      },
      {
        version = "4"
        name = "editor4"
      },
      {
        version = "5"
        name = "editor5"
      }
    ]
  }

  context = "./editor"
  ARGS = {
    REGISTRY = "my.registry/editor"
    APP_VERSION = versions.version
  }

  cache-from = [
    "type=registry,ref=my.registry/editor-${versions.name}:latest-build",
    "type=registry,ref=${buildtag("editor-${versions.name}")}",
  ]
  tags = ["my.registry/editor/${versions.name}:${TAG}"]
  cache-to = [
    "type=registry,ref=${buildtag("editor-${versions.name}")},mode=max",
  ]
}