Merge pull request #916 from nickhammond/buildpacks

Add pack option to the builder options for cloud native buildpacks

lib/kamal/commands/base.rb

@@ -84,6 +84,10 @@ module Kamal::Commands
         args.compact.unshift :docker
       end
 
+      def pack(*args)
+        args.compact.unshift :pack
+      end
+
       def git(*args, path: nil)
         [ :git, *([ "-C", path ] if path), *args.compact ]
       end

lib/kamal/commands/builder.rb

@@ -2,7 +2,7 @@ require "active_support/core_ext/string/filters"
 
 class Kamal::Commands::Builder < Kamal::Commands::Base
   delegate :create, :remove, :dev, :push, :clean, :pull, :info, :inspect_builder, :validate_image, :first_mirror, to: :target
-  delegate :local?, :remote?, :cloud?, to: "config.builder"
+  delegate :local?, :remote?, :pack?, :cloud?, to: "config.builder"
 
   include Clone
 
@@ -17,6 +17,8 @@ class Kamal::Commands::Builder < Kamal::Commands::Base
       else
         remote
       end
+    elsif pack?
+      pack
     elsif cloud?
       cloud
     else
@@ -36,6 +38,10 @@ class Kamal::Commands::Builder < Kamal::Commands::Base
     @hybrid ||= Kamal::Commands::Builder::Hybrid.new(config)
   end
 
+  def pack
+    @pack ||= Kamal::Commands::Builder::Pack.new(config)
+  end
+
   def cloud
     @cloud ||= Kamal::Commands::Builder::Cloud.new(config)
   end

lib/kamal/commands/builder/base.rb

@@ -6,6 +6,7 @@ class Kamal::Commands::Builder::Base < Kamal::Commands::Base
   delegate :argumentize, to: Kamal::Utils
   delegate \
     :args, :secrets, :dockerfile, :target, :arches, :local_arches, :remote_arches, :remote,
+    :pack?, :pack_builder, :pack_buildpacks,
     :cache_from, :cache_to, :ssh, :provenance, :sbom, :driver, :docker_driver?,
     to: :builder_config
 

lib/kamal/commands/builder/pack.rb

@@ -0,0 +1,46 @@
+class Kamal::Commands::Builder::Pack < Kamal::Commands::Builder::Base
+  def push(export_action = "registry")
+    combine \
+      build,
+      export(export_action)
+  end
+
+  def remove;end
+
+  def info
+    pack :builder, :inspect, pack_builder
+  end
+  alias_method :inspect_builder, :info
+
+  private
+    def build
+      pack(:build,
+        config.repository,
+        "--platform", platform,
+        "--creation-time", "now",
+        "--builder", pack_builder,
+        buildpacks,
+        "-t", config.absolute_image,
+        "-t", config.latest_image,
+        "--env", "BP_IMAGE_LABELS=service=#{config.service}",
+        *argumentize("--env", args),
+        *argumentize("--env", secrets, sensitive: true),
+        "--path", build_context)
+    end
+
+    def export(export_action)
+      return unless export_action == "registry"
+
+      combine \
+        docker(:push, config.absolute_image),
+        docker(:push, config.latest_image)
+    end
+
+    def platform
+      "linux/#{local_arches.first}"
+    end
+
+    def buildpacks
+      (pack_buildpacks << "paketo-buildpacks/image-labels").map { |buildpack| [ "--buildpack", buildpack ] }
+    end
+end

lib/kamal/configuration/builder.rb

@@ -61,6 +61,10 @@ class Kamal::Configuration::Builder
     !!builder_config["cache"]
   end
 
+  def pack?
+    !!builder_config["pack"]
+  end
+
   def args
     builder_config["args"] || {}
   end
@@ -85,6 +89,14 @@ class Kamal::Configuration::Builder
     builder_config.fetch("driver", "docker-container")
   end
 
+  def pack_builder
+    builder_config["pack"]["builder"] if pack?
+  end
+
+  def pack_buildpacks
+    builder_config["pack"]["buildpacks"] if pack?
+  end
+
   def local_disabled?
     builder_config["local"] == false
   end

lib/kamal/configuration/docs/builder.yml

@@ -8,7 +8,6 @@
 #
 # Options go under the builder key in the root configuration.
 builder:
-
   # Arch
   #
   # The architectures to build for — you can set an array or just a single value.
@@ -31,6 +30,19 @@ builder:
   # Defaults to true:
   local: true
 
+  # Buildpack configuration
+  #
+  # The build configuration for using pack to build a Cloud Native Buildpack image.
+  #
+  # For additional buildpack customization options you can create a project descriptor
+  # file(project.toml) that the Pack CLI will automatically use.
+  # See https://buildpacks.io/docs/for-app-developers/how-to/build-inputs/use-project-toml/ for more information.
+  pack:
+    builder: heroku/builder:24
+    buildpacks:
+      - heroku/ruby
+      - heroku/procfile
+
   # Builder cache
   #
   # The type must be either 'gha' or 'registry'.

lib/kamal/configuration/validator/builder.rb

@@ -8,6 +8,8 @@ class Kamal::Configuration::Validator::Builder < Kamal::Configuration::Validator
 
     error "Builder arch not set" unless config["arch"].present?
 
+    error "buildpacks only support building for one arch" if config["pack"] && config["arch"].is_a?(Array) && config["arch"].size > 1
+
     error "Cannot disable local builds, no remote is set" if config["local"] == false && config["remote"].blank?
   end
 end