Implement translation pause action

Leverage ngx.sleep() to mimic ModSecurity's pause action. We label
this as nondisruptive instead of disruptive, as this will not
block the worker or any other request.

lib/resty/waf/actions.lua

@@ -66,6 +66,11 @@ _M.nondisruptive_lookup = {
 
 		storage.set_var(waf, ctx, data, value)
 	end,
+	sleep = function(waf, time)
+		logger.log(waf, "Sleeping for " .. time)
+
+		ngx.sleep(time)
+	end,
 }
 
 return _M

t/translate/15_translate_actions.t

@@ -868,6 +868,58 @@ warning_like
 	'warn when setvar sets not value, but does not prepend !'
 ;
 
+$translation = {};
+translate_actions(
+	{
+		actions => [
+			{
+				action => 'pause',
+				value  => 5000,
+			}
+		]
+	},
+	$translation,
+	undef
+);
+is_deeply(
+	$translation,
+	{
+		actions => {
+			nondisrupt => [ {
+				action => 'sleep',
+				data   => 5,
+			} ]
+		}
+	},
+	'translate pause'
+);
+
+$translation = {};
+translate_actions(
+	{
+		actions => [
+			{
+				action => 'pause',
+				value  => 125,
+			}
+		]
+	},
+	$translation,
+	undef
+);
+is_deeply(
+	$translation,
+	{
+		actions => {
+			nondisrupt => [ {
+				action => 'sleep',
+				data   => 0.125,
+			} ]
+		}
+	},
+	'translate pause with decimal value'
+);
+
 $translation = {};
 translate_actions(
 	{

t/unit/actions/nondisruptive/05_sleep.t

@@ -0,0 +1,42 @@
+use Test::Nginx::Socket::Lua;
+
+repeat_each(3);
+plan tests => repeat_each() * 4 * blocks();
+
+no_shuffle();
+run_tests();
+
+__DATA__
+
+=== TEST 1: sleep calls ngx.sleep
+--- http_config
+init_by_lua_block{
+	if (os.getenv("LRW_COVERAGE")) then
+		runner = require "luacov.runner"
+		runner.tick = true
+		runner.init({savestepsize = 1})
+		jit.off()
+	end
+}
+--- config
+	location /t {
+		content_by_lua '
+			local actions = require "resty.waf.actions"
+
+			ngx.sleep = function(time)
+				ngx.say("Slept for " .. time .. " seconds")
+			end
+
+			actions.nondisruptive_lookup["sleep"]({ _debug = true, _debug_log_level = ngx.INFO }, 5)
+		';
+	}
+--- request
+GET /t
+--- error_code: 200
+--- response_body
+Slept for 5 seconds
+--- error_log
+Sleeping for 5
+--- no_error_log
+[error]
+

tools/Modsec2LRW.pm

@@ -821,6 +821,14 @@ sub translate_actions {
 					action => 'setvar',
 					data   => $setvar
 				};
+		} elsif ($key eq 'pause') {
+			my $time = $value / 1000; # pause:n is given in ms, ngx.sleep takes its arg as seconds
+
+			push @{$translation->{actions}->{nondisrupt}},
+				{
+					action => 'sleep',
+					data   => $time,
+				};
 		} elsif ($key eq 't') {
 			next if $value eq 'none';