Merge branch 'timeout-for-rest2html' into 'master'

Wrap call to rest2html in a timeout

See merge request !33

lib/github/markup/command_implementation.rb

@@ -12,6 +12,8 @@ module GitHub
     end
 
     class CommandImplementation < Implementation
+      DEFAULT_GITLAB_MARKUP_TIMEOUT = '10'.freeze
+
       attr_reader :command, :block, :name
 
       def initialize(regexp, command, name, &block)
@@ -27,7 +29,8 @@ module GitHub
         call_block(rendered, content)
       end
 
-    private
+      private
+
       def call_block(rendered, content)
         if block && block.arity == 2
           block.call(rendered, content)
@@ -38,20 +41,41 @@ module GitHub
         end
       end
 
+      def timeout_in_seconds
+        ENV.fetch('GITLAB_MARKUP_TIMEOUT', DEFAULT_GITLAB_MARKUP_TIMEOUT)
+      end
+
+      def prepend_command_timeout_prefix(command)
+        timeout_command_prefix = "timeout --signal=KILL #{timeout_in_seconds}"
+
+        # Preserve existing support for command being either a String or an Array
+        if command.is_a?(String)
+          "#{timeout_command_prefix} #{command}"
+        else
+          timeout_command_prefix.split(' ') + command
+        end
+      end
+
       if defined?(POSIX::Spawn)
         def execute(command, target)
-          spawn = POSIX::Spawn::Child.new(*command, :input => target)
+          command_with_timeout_prefix = prepend_command_timeout_prefix(command)
+          spawn = POSIX::Spawn::Child.new(*command_with_timeout_prefix, :input => target)
           if spawn.status.success?
             sanitize(spawn.out, target.encoding)
+          elsif spawn.status.termsig == Signal.list['KILL']
+            raise TimeoutError.new("Command was killed, probably due to exceeding GITLAB_MARKUP_TIMEOUT limit of #{timeout_in_seconds} seconds")
           else
             raise CommandError.new(spawn.err.strip)
           end
         end
       else
         def execute(command, target)
-          stdout_str, stderr_str, status = Open3.capture3(*command, stdin_data: target)
+          command_with_timeout_prefix = prepend_command_timeout_prefix(command)
+          stdout_str, stderr_str, status = Open3.capture3(*command_with_timeout_prefix, stdin_data: target)
           if status.success?
             sanitize(stdout_str, target.encoding)
+          elsif status.termsig == Signal.list['KILL']
+            raise TimeoutError.new("Command was killed, probably due to exceeding GITLAB_MARKUP_TIMEOUT limit of #{timeout_in_seconds} seconds")
           else
             raise CommandError.new(stderr_str.strip)
           end