Support Heroku-24 and multi-arch (#1439)

Heroku-24 base image supports two architectures amd64 and arm64. We've built binaries for these two architectures heroku/docker-heroku-ruby-builder#38. Effectively this means that the s3 bucket that holds the Ruby binaries has an additional folder. Previously files were at `<stack>/ruby-<version>.tgz` now they are at `<stack>/<arch>/ruby-<version>.tgz` but only for `heroku-24` and future stacks moving forward.

To support multiple architectures, the buildpack needs to detect the current architecture and whether or not the current stack supports multiple architectures.

Beyond downloading binaries, the buildpack is aware of the S3 structure to travers version numbers in order to warn customers when a newer version of a ruby version is available. We also warn customers if their current Ruby version is not available on the next stack. This behavior is implemented and tested in this commit, however we're not turning on warnings for `heroku-24` yet as customers cannot currently use it.

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## [Unreleased]
 
+- Heroku-24 stack initial support. Includes multi-architecture (arm64/amd64) logic that has not been tested on the platform (https://github.com/heroku/heroku-buildpack-ruby/pull/1439)
 - Remove unused Rubinius and Ruby 1.9.2 codepaths (https://github.com/heroku/heroku-buildpack-ruby/pull/1440)
 
 ## [v267] - 2024-02-28

lib/language_pack/base.rb

@@ -20,6 +20,8 @@ class LanguagePack::Base
   VENDOR_URL           = ENV['BUILDPACK_VENDOR_URL'] || "https://heroku-buildpack-ruby.s3.us-east-1.amazonaws.com"
   DEFAULT_LEGACY_STACK = "cedar"
   ROOT_DIR             = File.expand_path("../../..", __FILE__)
+  MULTI_ARCH_STACKS    = ["heroku-24"]
+  KNOWN_ARCHITECTURES  = ["amd64", "arm64"]
 
   attr_reader :build_path, :cache, :stack
 
@@ -35,10 +37,25 @@ def initialize(build_path, cache_path = nil, layer_dir=nil)
     @id            = Digest::SHA1.hexdigest("#{Time.now.to_f}-#{rand(1000000)}")[0..10]
     @fetchers      = {:buildpack => LanguagePack::Fetcher.new(VENDOR_URL) }
     @layer_dir     = layer_dir
+    @arch = get_arch
 
     Dir.chdir build_path
   end
 
+  def get_arch
+    command = "dpkg --print-architecture"
+    arch = run!(command, silent: true).strip
+
+    if !KNOWN_ARCHITECTURES.include?(arch)
+      raise <<~EOF
+        Architecture '#{arch}' returned from command `#{command}` is unknown.
+        Known architectures include: #{KNOWN_ARCHITECTURES.inspect}"
+      EOF
+    end
+
+    arch
+  end
+
   def self.===(build_path)
     raise "must subclass"
   end

lib/language_pack/fetcher.rb

@@ -7,10 +7,11 @@ class FetchError < StandardError; end
 
     include ShellHelpers
 
-    def initialize(host_url, stack: nil)
+    def initialize(host_url, stack: nil, arch: nil)
       @host_url = Pathname.new(host_url)
       # File.basename prevents accidental directory traversal
       @host_url += File.basename(stack) if stack
+      @host_url += File.basename(arch) if arch
     end
 
     def exists?(path, max_attempts = 1)

lib/language_pack/helpers/download_presence.rb

@@ -18,13 +18,17 @@
 class LanguagePack::Helpers::DownloadPresence
   STACKS = ['heroku-20', 'heroku-22']
 
-  def initialize(file_name:, stacks: STACKS)
+  def initialize(file_name:, arch: , multi_arch_stacks:, stacks: STACKS )
     @file_name = file_name
     @stacks = stacks
     @fetchers = []
     @threads = []
     @stacks.each do |stack|
-      @fetchers << LanguagePack::Fetcher.new(LanguagePack::Base::VENDOR_URL, stack: stack)
+      if multi_arch_stacks.include?(stack)
+        @fetchers << LanguagePack::Fetcher.new(LanguagePack::Base::VENDOR_URL, stack: stack, arch: arch)
+      else
+        @fetchers << LanguagePack::Fetcher.new(LanguagePack::Base::VENDOR_URL, stack: stack)
+      end
     end
   end
 

lib/language_pack/helpers/outdated_ruby_version.rb

@@ -8,6 +8,7 @@
 #   outdated = LanguagePack::Helpers::OutdatedRubyVersion.new(
 #     current_ruby_version: ruby_version,
 #     fetcher: LanguagePack::Fetcher.new(LanguagePack::Base::VENDOR_URL, stack: "heroku-22")
+#     fetcher: LanguagePack::Fetcher.new(LanguagePack::Base::VENDOR_URL, stack: "heroku-22", arch: "amd64")
 #   )
 #
 #   outdated.call

lib/language_pack/installers/heroku_ruby_installer.rb

@@ -10,8 +10,12 @@ class LanguagePack::Installers::HerokuRubyInstaller
   include LanguagePack::ShellHelpers
   attr_reader :fetcher
 
-  def initialize(stack: )
-    @fetcher = LanguagePack::Fetcher.new(BASE_URL, stack: stack)
+  def initialize(stack: , multi_arch_stacks: , arch: )
+    if multi_arch_stacks.include?(stack)
+      @fetcher = LanguagePack::Fetcher.new(BASE_URL, stack: stack, arch: arch)
+    else
+      @fetcher = LanguagePack::Fetcher.new(BASE_URL, stack: stack)
+    end
   end
 
   def install(ruby_version, install_dir)

lib/language_pack/ruby.rb

@@ -514,11 +514,15 @@ def install_ruby(install_path)
     return false unless ruby_version
 
     installer = LanguagePack::Installers::HerokuRubyInstaller.new(
+      multi_arch_stacks: MULTI_ARCH_STACKS,
       stack: @stack,
+      arch: @arch
     )
 
     @ruby_download_check = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: MULTI_ARCH_STACKS,
       file_name: ruby_version.file_name,
+      arch: @arch
     )
     @ruby_download_check.call
 

spec/helpers/download_presence_spec.rb

@@ -1,10 +1,44 @@
 require "spec_helper"
 
 describe LanguagePack::Helpers::DownloadPresence do
+  it "handles multi-arch transitions for files that exist" do
+    download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: ["heroku-24"],
+      file_name: 'ruby-3.1.4.tgz',
+      stacks: ["heroku-22", "heroku-24"],
+      arch: "amd64"
+    )
+
+    download.call
+
+    expect(download.next_stack(current_stack: "heroku-22")).to eq("heroku-24")
+    expect(download.next_stack(current_stack: "heroku-24")).to be_falsey
+
+    expect(download.exists_on_next_stack?(current_stack:"heroku-22")).to be_truthy
+  end
+
+  it "handles multi-arch transitions for files that do not exist" do
+    download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: ["heroku-24"],
+      file_name: 'ruby-3.0.5.tgz',
+      stacks: ["heroku-20", "heroku-24"],
+      arch: "amd64"
+    )
+
+    download.call
+
+    expect(download.next_stack(current_stack: "heroku-20")).to eq("heroku-24")
+    expect(download.next_stack(current_stack: "heroku-24")).to be_falsey
+
+    expect(download.exists_on_next_stack?(current_stack:"heroku-20")).to be_falsey
+  end
+
   it "knows if exists on the next stack" do
     download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: [],
       file_name: 'ruby-3.1.4.tgz',
       stacks: ['heroku-20', 'heroku-22'],
+      arch: nil
     )
 
     download.call
@@ -17,8 +51,10 @@
 
   it "detects when a package is present on higher stacks" do
     download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: [],
       file_name: 'ruby-2.6.5.tgz',
       stacks: ['cedar-14', 'heroku-16', 'heroku-18'],
+      arch: nil
     )
 
     download.call
@@ -32,8 +68,10 @@
 
   it "detects when a package is not present on higher stacks" do
     download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: [],
       file_name: 'ruby-1.9.3.tgz',
       stacks: ['cedar-14', 'heroku-16', 'heroku-18'],
+      arch: nil
     )
 
     download.call
@@ -44,8 +82,10 @@
 
   it "detects when a package is present on two stacks but not a third" do
     download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: [],
       file_name: 'ruby-2.3.0.tgz',
       stacks: ['cedar-14', 'heroku-16', 'heroku-18'],
+      arch: nil
     )
 
     download.call
@@ -56,8 +96,10 @@
 
   it "detects when a package does not exist" do
     download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: [],
       file_name: 'does-not-exist.tgz',
       stacks: ['cedar-14', 'heroku-16', 'heroku-18'],
+      arch: nil
     )
 
     download.call
@@ -68,7 +110,9 @@
 
   it "detects default ruby version" do
     download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: [],
       file_name: "ruby-3.1.1.tgz",
+      arch: nil
     )
 
     download.call
@@ -79,7 +123,9 @@
 
   it "handles the current stack not being in the known stacks list" do
     download = LanguagePack::Helpers::DownloadPresence.new(
+      multi_arch_stacks: [],
       file_name: "#{LanguagePack::RubyVersion::DEFAULT_VERSION}.tgz",
+      arch: nil
     )
 
     download.call

spec/helpers/outdated_ruby_version_spec.rb

@@ -6,6 +6,38 @@
     LanguagePack::Fetcher.new(LanguagePack::Base::VENDOR_URL, stack: stack)
   }
 
+  it "handles amd ↗️ architecture on heroku-24" do
+    ruby_version = LanguagePack::RubyVersion.new("ruby-3.1.0")
+    fetcher = LanguagePack::Fetcher.new(
+      LanguagePack::Base::VENDOR_URL,
+      stack: "heroku-24",
+      arch: "amd64"
+    )
+    outdated = LanguagePack::Helpers::OutdatedRubyVersion.new(
+      current_ruby_version: ruby_version,
+      fetcher: fetcher
+    )
+
+    outdated.call
+    expect(outdated.suggested_ruby_minor_version).to eq("3.1.4")
+  end
+
+  it "handles arm 💪 architecture on heroku-24" do
+    ruby_version = LanguagePack::RubyVersion.new("ruby-3.1.0")
+    fetcher = LanguagePack::Fetcher.new(
+      LanguagePack::Base::VENDOR_URL,
+      stack: "heroku-24",
+      arch: "arm64"
+    )
+    outdated = LanguagePack::Helpers::OutdatedRubyVersion.new(
+      current_ruby_version: ruby_version,
+      fetcher: fetcher
+    )
+
+    outdated.call
+    expect(outdated.suggested_ruby_minor_version).to eq("3.1.4")
+  end
+
   it "finds the latest version on a stack" do
     ruby_version = LanguagePack::RubyVersion.new("ruby-2.2.5")
     outdated = LanguagePack::Helpers::OutdatedRubyVersion.new(

spec/installers/heroku_ruby_installer_spec.rb

@@ -1,9 +1,13 @@
 require "spec_helper"
 
 describe LanguagePack::Installers::HerokuRubyInstaller do
-  let(:installer)    { LanguagePack::Installers::HerokuRubyInstaller.new(
-    stack: "cedar-14"
-  ) }
+  let(:installer) {
+    LanguagePack::Installers::HerokuRubyInstaller.new(
+      multi_arch_stacks: [],
+      stack: "cedar-14",
+      arch: nil,
+    )
+  }
   let(:ruby_version) { LanguagePack::RubyVersion.new("ruby-2.3.3") }
 
   describe "#fetch_unpack" do