Import EE License Automatically During Install

- Represent the path to an Enterprise Edition license file using the
  environment variable `GITLAB_LICENSE_FILE`
- Document how to properly configure `GITLAB_LICENSE_FILE` environment
  variable in source and omnibus installations.
- Detect and automatically install the GitLab license during source
  installation if present in the `config` directory and named
  `Gitlab.gitlab-license`

Resolves: https://gitlab.com/gitlab-org/gitlab-ee/issues/10808Signed-off-by: Robert Marshall <rmarshall@gitlab.com>

ee/changelogs/unreleased/10808-allow-license-import-during-install.yml

+---
+title: Allow adding GitLab license at installation time
+merge_request: 11244
+author:
+type: added

ee/db/fixtures/production/010_license.rb

+# frozen_string_literal: true
+
+default_license_file = Settings.source.dirname + 'Gitlab.gitlab-license'
+license_file = Pathname.new(ENV.fetch('GITLAB_LICENSE_FILE', default_license_file))
+
+# Do not fail if the license was not specified in configuration or a file
+# placed at the expected locations.
+if license_file.exist?
+  if ::License.new(data: license_file.read).save
+    puts "License Added:\n\nFilePath: #{license_file}".color(:green)
+  else
+    puts "License Invalid:\n\nFilePath: #{license_file}".color(:red)
+    raise "License Invalid"
+  end
+elsif !ENV['GITLAB_LICENSE_FILE'].blank?
+  puts "License File Missing:\n\nFilePath: #{license_file}".color(:red)
+  raise "License File Missing"
+end

ee/spec/db/production/license_spec.rb

+# frozen_string_literal: true
+require 'spec_helper'
+
+describe 'Automated License Installation' do
+  subject { load Rails.root.join('ee', 'db', 'fixtures', 'production', '010_license.rb') }
+
+  it 'works when no license to be installed' do
+    expect { subject }.not_to raise_error
+  end
+
+  context 'when GITLAB_LICENSE_FILE env variable is set' do
+    let(:license_path) { 'arbitrary_file_name' }
+
+    before do
+      stub_env('GITLAB_LICENSE_FILE', license_path)
+    end
+
+    it 'fails when the file does not exist' do
+      license_file = double('Pathname', exist?: false)
+      allow(Pathname).to receive(:new).and_call_original
+      expect(Pathname).to receive(:new).with(license_path).and_return(license_file)
+      expect { subject }.to raise_error(RuntimeError, "License File Missing")
+    end
+
+    context 'when the file does exist' do
+      before do
+        license_file = double('Pathname', exist?: true, read: license_file_contents)
+        allow(Pathname).to receive(:new).and_call_original
+        expect(Pathname).to receive(:new).with(license_path).and_return(license_file)
+      end
+
+      context 'and contains a valid license' do
+        let(:license_file_contents) { 'valid contents' }
+
+        it 'succeeds in adding the license' do
+          license = double('License', save: true)
+          expect(License).to receive(:new).with(data: license_file_contents).and_return(license)
+
+          expect { subject }.not_to raise_error
+        end
+      end
+
+      context 'but does not contain a valid license' do
+        let(:license_file_contents) { 'invalid contents' }
+
+        it 'fails to add the license' do
+          license = double('License', save: false)
+          expect(License).to receive(:new).with(data: license_file_contents).and_return(license)
+
+          expect { subject }.to raise_error(RuntimeError, "License Invalid")
+        end
+      end
+    end
+  end
+end