Backport changes from EE

Now the files are identical again compared to EE.

These are backported from
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/5050

app/models/upload.rb

@@ -12,6 +12,7 @@ class Upload < ActiveRecord::Base
   validates :uploader, presence: true
 
   scope :with_files_stored_locally, -> { where(store: ObjectStorage::Store::LOCAL) }
+  scope :with_files_stored_remotely, -> { where(store: ObjectStorage::Store::REMOTE) }
 
   before_save  :calculate_checksum!, if: :foreground_checksummable?
   after_commit :schedule_checksum,   if: :checksummable?
@@ -46,7 +47,18 @@ class Upload < ActiveRecord::Base
   end
 
   def exist?
-    File.exist?(absolute_path)
+    exist = File.exist?(absolute_path)
+
+    # Help sysadmins find missing upload files
+    if persisted? && !exist
+      if Gitlab::Sentry.enabled?
+        Raven.capture_message("Upload file does not exist", extra: self.attributes)
+      end
+
+      Gitlab::Metrics.counter(:upload_file_does_not_exist_total, 'The number of times an upload record could not find its file').increment
+    end
+
+    exist
   end
 
   def uploader_context

doc/administration/monitoring/prometheus/gitlab_metrics.md

@@ -45,6 +45,7 @@ The following metrics are available:
 | redis_ping_success                | Gauge     | 9.4   | Whether or not the last redis ping succeeded |
 | redis_ping_latency_seconds        | Gauge     | 9.4   | Round trip time of the redis ping |
 | user_session_logins_total         | Counter   | 9.4   | Counter of how many users have logged in |
+| upload_file_does_not_exist        | Counter   | 10.7  | Number of times an upload record could not find its file |
 | failed_login_captcha_total        | Gauge | 11.0 | Counter of failed CAPTCHA attempts during login |
 | successful_login_captcha_total    | Gauge | 11.0 | Counter of successful CAPTCHA attempts during login |
 

spec/models/upload_spec.rb

@@ -112,11 +112,52 @@ describe Upload do
       expect(upload).to exist
     end
 
-    it 'returns false when the file does not exist' do
+    context 'when the file does not exist' do
+      it 'returns false' do
         upload = described_class.new(path: "#{__FILE__}-nope", store: ObjectStorage::Store::LOCAL)
 
         expect(upload).not_to exist
       end
+
+      context 'when the record is persisted' do
+        it 'sends a message to Sentry' do
+          upload = create(:upload, :issuable_upload)
+
+          expect(Gitlab::Sentry).to receive(:enabled?).and_return(true)
+          expect(Raven).to receive(:capture_message).with("Upload file does not exist", extra: upload.attributes)
+
+          upload.exist?
+        end
+
+        it 'increments a metric counter to signal a problem' do
+          upload = create(:upload, :issuable_upload)
+
+          counter = double(:counter)
+          expect(counter).to receive(:increment)
+          expect(Gitlab::Metrics).to receive(:counter).with(:upload_file_does_not_exist_total, 'The number of times an upload record could not find its file').and_return(counter)
+
+          upload.exist?
+        end
+      end
+
+      context 'when the record is not persisted' do
+        it 'does not send a message to Sentry' do
+          upload = described_class.new(path: "#{__FILE__}-nope", store: ObjectStorage::Store::LOCAL)
+
+          expect(Raven).not_to receive(:capture_message)
+
+          upload.exist?
+        end
+
+        it 'does not increment a metric counter' do
+          upload = described_class.new(path: "#{__FILE__}-nope", store: ObjectStorage::Store::LOCAL)
+
+          expect(Gitlab::Metrics).not_to receive(:counter)
+
+          upload.exist?
+        end
+      end
+    end
   end
 
   describe "#uploader_context" do