1 files changed, 99 insertions, 0 deletions
diff --git a/app/services/design_management/generate_image_versions_service.rb b/app/services/design_management/generate_image_versions_service.rb
new file mode 100644
index 00000000000..213aac164ff
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+++ b/app/services/design_management/generate_image_versions_service.rb
@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+module DesignManagement
+  # This service generates smaller image versions for `DesignManagement::Design`
+  # records within a given `DesignManagement::Version`.
+  class GenerateImageVersionsService < DesignService
+    # We limit processing to only designs with file sizes that don't
+    # exceed `MAX_DESIGN_SIZE`.
+    #
+    # Note, we may be able to remove checking this limit, if when we come to
+    # implement a file size limit for designs, there are no designs that
+    # exceed 40MB on GitLab.com
+    #
+    # See https://gitlab.com/gitlab-org/gitlab/-/merge_requests/22860#note_281780387
+    MAX_DESIGN_SIZE = 40.megabytes.freeze
+
+    def initialize(version)
+      super(version.project, version.author, issue: version.issue)
+
+      @version = version
+    end
+
+    def execute
+      # rubocop: disable CodeReuse/ActiveRecord
+      version.actions.includes(:design).each do |action|
+        generate_image(action)
+      end
+      # rubocop: enable CodeReuse/ActiveRecord
+
+      success(version: version)
+    end
+
+    private
+
+    attr_reader :version
+
+    def generate_image(action)
+      raw_file = get_raw_file(action)
+
+      unless raw_file
+        log_error("No design file found for Action: #{action.id}")
+        return
+      end
+
+      # Skip attempting to process images that would be rejected by CarrierWave.
+      return unless DesignManagement::DesignV432x230Uploader::MIME_TYPE_WHITELIST.include?(raw_file.content_type)
+
+      # Store and process the file
+      action.image_v432x230.store!(raw_file)
+      action.save!
+    rescue CarrierWave::UploadError => e
+      Gitlab::ErrorTracking.track_exception(e, project_id: project.id, design_id: action.design_id, version_id: action.version_id)
+      log_error(e.message)
+    end
+
+    # Returns the `CarrierWave::SanitizedFile` of the original design file
+    def get_raw_file(action)
+      raw_files_by_path[action.design.full_path]
+    end
+
+    # Returns the `Carrierwave:SanitizedFile` instances for all of the original
+    # design files, mapping to { design.filename => `Carrierwave::SanitizedFile` }.
+    #
+    # As design files are stored in Git LFS, the only way to retrieve their original
+    # files is to first fetch the LFS pointer file data from the Git design repository.
+    # The LFS pointer file data contains an "OID" that lets us retrieve `LfsObject`
+    # records, which have an Uploader (`LfsObjectUploader`) for the original design file.
+    def raw_files_by_path
+      @raw_files_by_path ||= begin
+        LfsObject.for_oids(blobs_by_oid.keys).each_with_object({}) do |lfs_object, h|
+          blob = blobs_by_oid[lfs_object.oid]
+          file = lfs_object.file.file
+          # The `CarrierWave::SanitizedFile` is loaded without knowing the `content_type`
+          # of the file, due to the file not having an extension.
+          #
+          # Set the content_type from the `Blob`.
+          file.content_type = blob.content_type
+          h[blob.path] = file
+        end
+      end
+    end
+
+    # Returns the `Blob`s that correspond to the design files in the repository.
+    #
+    # All design `Blob`s are LFS Pointer files, and are therefore small amounts
+    # of data to load.
+    #
+    # `Blob`s whose size are above a certain threshold: `MAX_DESIGN_SIZE`
+    # are filtered out.
+    def blobs_by_oid
+      @blobs ||= begin
+        items = version.designs.map { |design| [version.sha, design.full_path] }
+        blobs = repository.blobs_at(items)
+        blobs.reject! { |blob| blob.lfs_size > MAX_DESIGN_SIZE }
+        blobs.index_by(&:lfs_oid)
+      end
+    end
+  end
+end