GRN2-xx: Removed Health Check Gem (#840)

* Initial work on removing health check gem

* Added health checks

* Fixed gemfile

app/controllers/health_check_controller.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+# BigBlueButton open source conferencing system - http://www.bigbluebutton.org/.
+#
+# Copyright (c) 2018 BigBlueButton Inc. and by respective authors (see below).
+#
+# This program is free software; you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free Software
+# Foundation; either version 3.0 of the License, or (at your option) any later
+# version.
+#
+# BigBlueButton is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with BigBlueButton; if not, see <http://www.gnu.org/licenses/>.
+
+class HealthCheckController < ApplicationController
+  skip_before_action :redirect_to_https, :set_user_domain, :set_user_settings, :maintenance_mode?, :migration_error?,
+  :user_locale, :check_admin_password, :check_user_role
+
+  # GET /health_check
+  def all
+    response = "success"
+    @cache_expire = 10.seconds
+
+    begin
+      cache_check
+      database_check
+      email_check
+    rescue => e
+      response = "Health Check Failure: #{e}"
+    end
+
+    render plain: response
+  end
+
+  private
+
+  def cache_check
+    if Rails.cache.write("__health_check_cache_write__", "true", expires_in: @cache_expire)
+      raise "Unable to read from cache" unless Rails.cache.read("__health_check_cache_write__") == "true"
+    else
+      raise "Unable to write to cache"
+    end
+  end
+
+  def database_check
+    if defined?(ActiveRecord)
+      raise "Database not responding" unless ActiveRecord::Migrator.current_version
+    end
+    raise "Pending migrations" unless ActiveRecord::Migration.check_pending!.nil?
+  end
+
+  def email_check
+    test_smtp if Rails.configuration.action_mailer.delivery_method == :smtp
+  end
+
+  def test_smtp
+    settings = ActionMailer::Base.smtp_settings
+
+    smtp = Net::SMTP.new(settings[:address], settings[:port])
+    if settings[:enable_starttls_auto] == "true"
+      smtp.enable_starttls_auto if smtp.respond_to?(:enable_starttls_auto)
+    end
+
+    smtp.start(settings[:domain]) do |s|
+      s.authenticate(settings[:user_name], settings[:password], settings[:authentication])
+    end
+  rescue => e
+    raise "Unable to connect to SMTP Server - #{e}"
+  end
+end