Add latest changes from gitlab-org/gitlab@master

1 files changed, 51 insertions, 0 deletions

diff --git a/app/models/concerns/has_unique_internal_users.rb b/app/models/concerns/has_unique_internal_users.rb
new file mode 100644
index 00000000000..4d60cfa03b0
--- /dev/null
+++ b/app/models/concerns/has_unique_internal_users.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module HasUniqueInternalUsers
+  extend ActiveSupport::Concern
+
+  class_methods do
+    private
+
+    def unique_internal(scope, username, email_pattern, &block)
+      scope.first || create_unique_internal(scope, username, email_pattern, &block)
+    end
+
+    def create_unique_internal(scope, username, email_pattern, &creation_block)
+      # Since we only want a single one of these in an instance, we use an
+      # exclusive lease to ensure than this block is never run concurrently.
+      lease_key = "user:unique_internal:#{username}"
+      lease = Gitlab::ExclusiveLease.new(lease_key, timeout: 1.minute.to_i)
+
+      until uuid = lease.try_obtain
+        # Keep trying until we obtain the lease. To prevent hammering Redis too
+        # much we'll wait for a bit between retries.
+        sleep(1)
+      end
+
+      # Recheck if the user is already present. One might have been
+      # added between the time we last checked (first line of this method)
+      # and the time we acquired the lock.
+      existing_user = uncached { scope.first }
+      return existing_user if existing_user.present?
+
+      uniquify = Uniquify.new
+
+      username = uniquify.string(username) { |s| User.find_by_username(s) }
+
+      email = uniquify.string(-> (n) { Kernel.sprintf(email_pattern, n) }) do |s|
+        User.find_by_email(s)
+      end
+
+      user = scope.build(
+        username: username,
+        email: email,
+        &creation_block
+      )
+
+      Users::UpdateService.new(user, user: user).execute(validate: false)
+      user
+    ensure
+      Gitlab::ExclusiveLease.cancel(lease_key, uuid)
+    end
+  end
+end