Create CalculateFindingUUID service object

ee/lib/gitlab/vulnerabilities/calculate_finding_uuid.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Vulnerabilities
+    class CalculateFindingUUID
+      FINDING_NAMESPACES_IDS = {
+        development: "a143e9e2-41b3-47bc-9a19-081d089229f4",
+        test: "a143e9e2-41b3-47bc-9a19-081d089229f4",
+        staging: "a6930898-a1b2-4365-ab18-12aa474d9b26",
+        production:  "58dc0f06-936c-43b3-93bb-71693f1b6570"
+      }.freeze
+
+      NAMESPACE_REGEX = /(\h{8})-(\h{4})-(\h{4})-(\h{4})-(\h{4})(\h{8})/.freeze
+      PACK_PATTERN = "NnnnnN".freeze
+
+      def self.call(value)
+        Digest::UUID.uuid_v5(namespace_id, value)
+      end
+
+      def self.namespace_id
+        namespace_uuid = FINDING_NAMESPACES_IDS.fetch(Rails.env.to_sym)
+        # Digest::UUID is broken when using an UUID in namespace_id
+        # https://github.com/rails/rails/issues/37681#issue-520718028
+        namespace_uuid.scan(NAMESPACE_REGEX).flatten.map { |s| s.to_i(16) }.pack(PACK_PATTERN)
+      end
+    end
+  end
+end

ee/spec/lib/gitlab/vulnerabilities/calculate_finding_uuid_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Vulnerabilities::CalculateFindingUUID do
+  let_it_be(:value) { "GitLab" }
+
+  subject { described_class.call(value) }
+
+  context 'in development' do
+    let_it_be(:development_proper_uuid) { "5b593e54-90f5-504b-8805-5394a4d14b94" }
+
+    before do
+      allow(Rails).to receive(:env).and_return(:development)
+    end
+
+    it { is_expected.to eq(development_proper_uuid) }
+  end
+
+  context 'in test' do
+    let_it_be(:test_proper_uuid) { "5b593e54-90f5-504b-8805-5394a4d14b94" }
+
+    it { is_expected.to eq(test_proper_uuid) }
+  end
+
+  context 'in staging' do
+    let_it_be(:staging_proper_uuid) { "dd190b37-7754-5c7c-80a0-85621a5823ad" }
+
+    before do
+      allow(Rails).to receive(:env).and_return(:staging)
+    end
+
+    it { is_expected.to eq(staging_proper_uuid) }
+  end
+
+  context 'in production' do
+    let_it_be(:production_proper_uuid) { "4961388b-9d8e-5da0-a499-3ef5da58daf0" }
+
+    before do
+      allow(Rails).to receive(:env).and_return(:production)
+    end
+
+    it { is_expected.to eq(production_proper_uuid) }
+  end
+end