Auto-detect if colors are supported

Not all output supports colors. For example, cron doesn't. This copies
the autodetection from Kafo to disable colors if needed.

lib/foreman_maintain.rb

@@ -68,6 +68,7 @@ def setup(options = {})
 
       # using a queue, we can log the messages which are generated before initializing logger
       self.config = Config.new(options)
+      configure_highline
       load_definitions
       init_logger
       update_path
@@ -102,6 +103,10 @@ def load_definitions
       end
     end
 
+    def configure_highline
+      HighLine.use_color = config.use_color?
+    end
+
     def cache
       ObjectCache.instance
     end

lib/foreman_maintain/config.rb

@@ -25,6 +25,11 @@ def initialize(options)
       @foreman_port = @options.fetch(:foreman_port, 443)
     end
 
+    def use_color?
+      ENV['TERM'] && ENV.fetch('NO_COLOR', '') == '' && \
+        system('command -v tput', out: File.open('/dev/null')) && `tput colors`.to_i > 0
+    end
+
     private
 
     def load_log_configs

test/lib/cli/health_command_test.rb

@@ -40,10 +40,10 @@ module ForemanMaintain
           [dummy-check-fail-skipwhitelist] Check that ends up with fail
           [dummy-check-success] Check that ends up with success
           [dummy-check-warn] Check that ends up with warning
-          [external-service-is-accessible] External_service_is_accessible         [pre-upgrade-check]
-          [present-service-is-running] Present service run check                  [default]
-          [service-is-stopped] Service not running check                          [default]
-          [upgrade-post-upgrade-check] Procedures::Upgrade::PostUpgradeCheck      [post-upgrade-checks]
+          [external-service-is-accessible] External_service_is_accessible                  [pre-upgrade-check]
+          [present-service-is-running] Present service run check                           [default]
+          [service-is-stopped] Service not running check                                   [default]
+          [upgrade-post-upgrade-check] Procedures::Upgrade::PostUpgradeCheck               [post-upgrade-checks]
         OUTPUT
       end
     end

test/lib/reporter_test.rb

@@ -388,7 +388,6 @@ def captured_out(simulate_terminal = true)
       # simulate carriage returns to get the output as user would see it
       out = capture.read
       out = simulate_carriage_returns(out) if simulate_terminal
-      out = remove_colors(out)
       capture.rewind
       out
     end

test/test_helper.rb

@@ -1,3 +1,4 @@
+ENV['NO_COLOR'] = '1'
 require 'foreman_maintain'
 require 'minitest/spec'
 require 'minitest/autorun'
@@ -19,7 +20,7 @@ def assert_cmd(expected_output, args = [], ignore_whitespace: false)
       expected_output = expected_output.gsub(/\s+/, ' ')
       output = output.gsub(/\s+/, ' ')
     end
-    assert_equal expected_output, remove_colors(simulate_carriage_returns(output))
+    assert_equal expected_output, simulate_carriage_returns(output)
   end
 
   def capture_io_with_stderr
@@ -48,10 +49,6 @@ def run_cmd(args = [])
   def simulate_carriage_returns(output)
     output.gsub(/^.*\r/, '')
   end
-
-  def remove_colors(output)
-    output.gsub(/\e.*?m/, '')
-  end
 end
 
 class FakePackageManager < ForemanMaintain::PackageManager::Base