1 files changed, 46 insertions, 0 deletions
diff --git a/app/services/dependency_proxy/find_cached_manifest_service.rb b/app/services/dependency_proxy/find_cached_manifest_service.rb
new file mode 100644
index 00000000000..faf0402edaa
--- /dev/null
+++ b/app/services/dependency_proxy/find_cached_manifest_service.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+module DependencyProxy
+  class FindCachedManifestService < DependencyProxy::BaseService
+    def initialize(group, image, tag, token)
+      @group = group
+      @image = image
+      @tag = tag
+      @token = token
+      @file_name = "#{@image}:#{@tag}.json"
+      @manifest = nil
+    end
+
+    def execute
+      @manifest = @group.dependency_proxy_manifests
+                        .active
+                        .find_by_file_name_or_digest(file_name: @file_name, digest: @tag)
+
+      head_result = DependencyProxy::HeadManifestService.new(@image, @tag, @token).execute
+
+      return respond if cached_manifest_matches?(head_result)
+
+      success(manifest: nil, from_cache: false)
+    rescue Timeout::Error, *Gitlab::HTTP::HTTP_ERRORS
+      respond
+    end
+
+    private
+
+    def cached_manifest_matches?(head_result)
+      return false if head_result[:status] == :error
+
+      @manifest && @manifest.digest == head_result[:digest] && @manifest.content_type == head_result[:content_type]
+    end
+
+    def respond(from_cache: true)
+      if @manifest
+        @manifest.read!
+
+        success(manifest: @manifest, from_cache: from_cache)
+      else
+        error('Failed to download the manifest from the external registry', 503)
+      end
+    end
+  end
+end