Add docker rake tasks

tasks/docker.rake

@@ -0,0 +1,218 @@
+# frozen_string_literal: true
+
+# @type self: Rake::DSL
+
+# TODO: use rake dependency + satisfaction mechanism via `needs?`
+# See: https://github.com/ruby/rake/blob/03cb03474b4eb008b2d62ad96d07de0d6239c7ab/lib/rake/file_task.rb#L16
+
+namespace :docker do
+  def repository # TODO: rename to registry/registry host/user/path
+    "ghcr.io/datadog/images-rb"
+  end
+
+  def targets
+    @targets ||= Dir.glob("src/**/Dockerfile*").map do |f|
+      dockerfile = f
+      context = File.dirname(dockerfile)
+
+      image = "#{repository}/#{File.dirname(f.sub(/^src\//, "").sub(/\/Dockerfile(.*)/, ""))}"
+      tag = f.sub(/.*\/(\d+(?:\.\d+))+\//, "\\1").sub(/Dockerfile(.*)$/) { |m| m.sub("Dockerfile", "").tr(".", "-") }
+
+      {
+        dockerfile: dockerfile,
+        context: context,
+        image: image, # TODO: rename to repository
+        tag: tag
+        # TODO: rename to image/tag/tagged_image/name/alias: "#{repo}:#{tag}"
+      }
+    end
+  end
+
+  def dependencies
+    @dependencies ||= Dir.glob("src/**/Dockerfile*").each_with_object({}) do |path, h|
+      h[path] = File.read(path).each_line.with_object([]) { |l, a| l =~ /^FROM (\S+)(?:\s+AS|\s*$)/ && a << $1 }
+    end
+  end
+
+  def local_dependencies
+    @local_dependencies ||= dependencies.each_with_object({}) { |(k, v), h| h[k] = v.select { |from| from.start_with?(repository) } }
+  end
+
+  def target_for(args)
+    targets_for(args).tap { |a| a.size > 1 and fail "multiple args passed to task" }.first
+  end
+
+  def glob_match?(pattern, str)
+    re = Regexp.new("^#{Regexp.escape(pattern).gsub("\\*\\*", "[^:]*?").gsub("\\*", "[^/:]*?")}$")
+
+    !!(str =~ re)
+  end
+
+  def targets_for(args)
+    images = args.to_a
+
+    images.map do |image|
+      image = "#{repository}/#{image}" unless image.start_with?(repository)
+
+      found = targets.select { |e| glob_match?(image, "#{e[:image]}:#{e[:tag]}") }
+
+      fail "#{image} not found" if found.nil?
+
+      found
+    end.flatten
+  end
+
+  def dockerfiles_for(*images)
+    images.map do |image|
+      targets.each_with_object([]) { |t, a| a << t[:dockerfile] if "#{t[:image]}:#{t[:tag]}" == image }
+    end.flatten
+  end
+
+  def satisfied?(result, deps = [])
+    result_time = case result
+    when String
+      File.ctime(result).to_datetime
+    when Proc
+      result.call
+    else
+      raise ArgumentError, "invalid type: #{dep.class}"
+    end
+
+    return false if result_time.nil?
+    return true if deps.empty?
+
+    deps.map do |dep|
+      dep_time = case dep
+      when String
+        File.ctime(dep).to_datetime
+      when Proc
+        dep.call
+      else
+        raise ArgumentError, "invalid type: #{dep.class}"
+      end
+
+      result_time > dep_time
+    end.reduce(:&)
+  end
+
+  def docker_platform
+    if RUBY_PLATFORM =~ /^(?:universal\.|)(x86_64|aarch64|arm64)/
+      cpu = $1.sub(/arm64(:?e|)/, "aarch64")
+    else
+      raise ArgumentError, "unsupported platform: #{RUBY_PLATFORM}"
+    end
+
+    os = "linux"
+
+    "#{os}/#{cpu}"
+  end
+
+  def image_time(image)
+    require "time"
+
+    last_tag_time = `docker image inspect -f '{{ .Metadata.LastTagTime }}' '#{image}'`.chomp
+
+    if $?.to_i == 0
+      # "0001-01-01 00:00:00 +0000 UTC"
+      last_tag_time.sub!(/^(\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}:\d{2})(\s+)/, "\\1.0\\2")
+
+      DateTime.strptime(last_tag_time, "%Y-%m-%d %H:%M:%S.%N %z")
+    end
+  end
+
+  def volume_time(volume)
+    require "time"
+
+    volume_creation_time = `docker volume inspect -f '{{ .CreatedAt }}' '#{volume}'`.chomp
+
+    if $?.to_i == 0
+      volume_creation_time.sub!(/^(\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}:\d{2})(\s+)/, "\\1.0\\2")
+
+      DateTime.strptime(volume_creation_time, "%Y-%m-%dT%H:%M:%S.%N %z")
+    end
+  end
+
+  desc "List image targets."
+  task :list do
+    targets.each do |image|
+      puts "#{image[:image]}:#{image[:tag]}"
+    end
+  end
+
+  desc "Pull image."
+  task :pull do |_, args|
+    targets = targets_for(args)
+
+    targets.each do |target|
+      image = target[:image]
+      tag = target[:tag]
+      platform = docker_platform
+
+      sh "docker pull --platform #{platform} #{image}:#{tag} || true"
+    end
+  end
+
+  desc "Build image."
+  task :build do |_, args|
+    targets = targets_for(args)
+
+    targets.each do |target|
+      dockerfile = target[:dockerfile]
+      context = target[:context]
+      image = target[:image]
+      tag = target[:tag]
+      platform = docker_platform
+
+      deps = [
+        dockerfile
+      ] + dockerfiles_for(*local_dependencies[dockerfile])
+
+      compatible_platforms = deps.map do |dep|
+        File.read(dep).lines.select { |l| l =~ /^\s*#\s*platforms:/ }.map { |l| l =~ /platforms: (.*)/ && $1 }
+      end.flatten
+
+      if compatible_platforms.any? && !compatible_platforms.include?(platform)
+        warn "skip build: dockerfile: #{dockerfile.inspect}, incompatible platform: #{platform.inspect}, compatible platforms: #{compatible_platforms.inspect}"
+        next
+      end
+
+      local_dependencies[dockerfile].each { |dep| Rake::Task[:"docker:build"].execute(Rake::TaskArguments.new([], [dep])) }
+
+      next if satisfied?(-> { image_time("#{image}:#{tag}") }, deps)
+
+      sh "docker buildx build --platform #{platform} --cache-from=type=registry,ref=#{image}:#{tag} -f #{dockerfile} -t #{image}:#{tag} #{context}"
+    end
+  end
+
+  desc "Run container with default CMD."
+  task cmd: :build do |_, args|
+    target = target_for(args)
+
+    image = target[:image]
+    tag = target[:tag]
+    platform = docker_platform
+
+    exec "docker run --rm -it --platform #{platform} -v #{Dir.pwd}:#{Dir.pwd} -w #{Dir.pwd} #{image}:#{tag}"
+  end
+
+  desc "Run container with shell."
+  task shell: :build do |_, args|
+    target = target_for(args)
+
+    image = target[:image]
+    tag = target[:tag]
+    platform = docker_platform
+
+    exec "docker run --rm -it --platform #{platform} -v #{Dir.pwd}:#{Dir.pwd} -w #{Dir.pwd} #{image}:#{tag} /bin/sh"
+  end
+
+  desc "Run container with irb."
+  task irb: :build do |_, args|
+    target = target_for(args)
+
+    image = target[:image]
+    tag = target[:tag]
+
+    exec "docker run --rm -it --platform #{platform} -v #{Dir.pwd}:#{Dir.pwd} -w #{Dir.pwd} #{image}:#{tag} irb"
+  end
+end