From 20c0d9d4d73ed3016d638999accd18ca5c9a756b Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Fri, 8 Nov 2013 10:16:25 -0800
Subject: [PATCH] Made Lua code in JobQueueRedis more readable with unpack()

Change-Id: I52fb765a153acc7f16baa804ab2342e9b5dd9fd6
---
 includes/job/JobQueueRedis.php | 78 ++++++++++++++++++----------------
 1 file changed, 42 insertions(+), 36 deletions(-)

diff --git a/includes/job/JobQueueRedis.php b/includes/job/JobQueueRedis.php
index e8c475d074..5c3c5e9c62 100644
--- a/includes/job/JobQueueRedis.php
+++ b/includes/job/JobQueueRedis.php
@@ -251,23 +251,24 @@ class JobQueueRedis extends JobQueue {
 		}
 		static $script =
 <<<LUA
+		local kUnclaimed, kSha1ById, kIdBySha1, kDelayed, kData = unpack(KEYS)
 		if #ARGV % 4 ~= 0 then return redis.error_reply('Unmatched arguments') end
 		local pushed = 0
 		for i = 1,#ARGV,4 do
 			local id,sha1,rtimestamp,blob = ARGV[i],ARGV[i+1],ARGV[i+2],ARGV[i+3]
-			if sha1 == '' or redis.call('hExists',KEYS[3],sha1) == 0 then
+			if sha1 == '' or redis.call('hExists',kIdBySha1,sha1) == 0 then
 				if 1*rtimestamp > 0 then
 					-- Insert into delayed queue (release time as score)
-					redis.call('zAdd',KEYS[4],rtimestamp,id)
+					redis.call('zAdd',kDelayed,rtimestamp,id)
 				else
 					-- Insert into unclaimed queue
-					redis.call('lPush',KEYS[1],id)
+					redis.call('lPush',kUnclaimed,id)
 				end
 				if sha1 ~= '' then
-					redis.call('hSet',KEYS[2],id,sha1)
-					redis.call('hSet',KEYS[3],sha1,id)
+					redis.call('hSet',kSha1ById,id,sha1)
+					redis.call('hSet',kIdBySha1,sha1,id)
 				end
-				redis.call('hSet',KEYS[5],id,blob)
+				redis.call('hSet',kData,id,blob)
 				pushed = pushed + 1
 			end
 		end
@@ -343,16 +344,17 @@ LUA;
 	protected function popAndDeleteBlob( RedisConnRef $conn ) {
 		static $script =
 <<<LUA
+		local kUnclaimed, kSha1ById, kIdBySha1, kData = unpack(KEYS)
 		-- Pop an item off the queue
-		local id = redis.call('rpop',KEYS[1])
+		local id = redis.call('rpop',kUnclaimed)
 		if not id then return false end
 		-- Get the job data and remove it
-		local item = redis.call('hGet',KEYS[4],id)
-		redis.call('hDel',KEYS[4],id)
+		local item = redis.call('hGet',kData,id)
+		redis.call('hDel',kData,id)
 		-- Allow new duplicates of this job
-		local sha1 = redis.call('hGet',KEYS[2],id)
-		if sha1 then redis.call('hDel',KEYS[3],sha1) end
-		redis.call('hDel',KEYS[2],id)
+		local sha1 = redis.call('hGet',kSha1ById,id)
+		if sha1 then redis.call('hDel',kIdBySha1,sha1) end
+		redis.call('hDel',kSha1ById,id)
 		-- Return the job data
 		return item
 LUA;
@@ -375,17 +377,18 @@ LUA;
 	protected function popAndAcquireBlob( RedisConnRef $conn ) {
 		static $script =
 <<<LUA
+		local kUnclaimed, kSha1ById, kIdBySha1, kClaimed, kAttempts, kData = unpack(KEYS)
 		-- Pop an item off the queue
-		local id = redis.call('rPop',KEYS[1])
+		local id = redis.call('rPop',kUnclaimed)
 		if not id then return false end
 		-- Allow new duplicates of this job
-		local sha1 = redis.call('hGet',KEYS[2],id)
-		if sha1 then redis.call('hDel',KEYS[3],sha1) end
-		redis.call('hDel',KEYS[2],id)
+		local sha1 = redis.call('hGet',kSha1ById,id)
+		if sha1 then redis.call('hDel',kIdBySha1,sha1) end
+		redis.call('hDel',kSha1ById,id)
 		-- Mark the jobs as claimed and return it
-		redis.call('zAdd',KEYS[4],ARGV[1],id)
-		redis.call('hIncrBy',KEYS[5],id,1)
-		return redis.call('hGet',KEYS[6],id)
+		redis.call('zAdd',kClaimed,ARGV[1],id)
+		redis.call('hIncrBy',kAttempts,id,1)
+		return redis.call('hGet',kData,id)
 LUA;
 		return $conn->luaEval( $script,
 			array(
@@ -416,11 +419,12 @@ LUA;
 			try {
 				static $script =
 <<<LUA
+				local kClaimed, kAttempts, kData = unpack(KEYS)
 				-- Unmark the job as claimed
-				redis.call('zRem',KEYS[1],ARGV[1])
-				redis.call('hDel',KEYS[2],ARGV[1])
+				redis.call('zRem',kClaimed,ARGV[1])
+				redis.call('hDel',kAttempts,ARGV[1])
 				-- Delete the job data itself
-				return redis.call('hDel',KEYS[3],ARGV[1])
+				return redis.call('hDel',kData,ARGV[1])
 LUA;
 				$res = $conn->luaEval( $script,
 					array(
@@ -636,12 +640,13 @@ LUA;
 		try {
 			static $script =
 <<<LUA
+			local kDelayed, kUnclaimed = unpack(KEYS)
 			-- Get the list of ready delayed jobs, sorted by readiness
-			local ids = redis.call('zRangeByScore',KEYS[1],0,ARGV[1])
+			local ids = redis.call('zRangeByScore',kDelayed,0,ARGV[1])
 			-- Migrate the jobs from the "delayed" set to the "unclaimed" list
 			for k,id in ipairs(ids) do
-				redis.call('lPush',KEYS[2],id)
-				redis.call('zRem',KEYS[1],id)
+				redis.call('lPush',kUnclaimed,id)
+				redis.call('zRem',kDelayed,id)
 			end
 			return #ids
 LUA;
@@ -680,33 +685,34 @@ LUA;
 			$now = time();
 			static $script =
 <<<LUA
+			local kClaimed, kAttempts, kUnclaimed, kData, kAbandoned = unpack(KEYS)
 			local released,abandoned,pruned = 0,0,0
 			-- Get all non-dead jobs that have an expired claim on them.
 			-- The score for each item is the last claim timestamp (UNIX).
-			local staleClaims = redis.call('zRangeByScore',KEYS[1],0,ARGV[1])
+			local staleClaims = redis.call('zRangeByScore',kClaimed,0,ARGV[1])
 			for k,id in ipairs(staleClaims) do
-				local timestamp = redis.call('zScore',KEYS[1],id)
-				local attempts = redis.call('hGet',KEYS[2],id)
+				local timestamp = redis.call('zScore',kClaimed,id)
+				local attempts = redis.call('hGet',kAttempts,id)
 				if attempts < ARGV[3] then
 					-- Claim expired and retries left: re-enqueue the job
-					redis.call('lPush',KEYS[3],id)
-					redis.call('hIncrBy',KEYS[2],id,1)
+					redis.call('lPush',kUclaimed,id)
+					redis.call('hIncrBy',kAttempts,id,1)
 					released = released + 1
 				else
 					-- Claim expired and no retries left: mark the job as dead
-					redis.call('zAdd',KEYS[5],timestamp,id)
+					redis.call('zAdd',kAbandoned,timestamp,id)
 					abandoned = abandoned + 1
 				end
-				redis.call('zRem',KEYS[1],id)
+				redis.call('zRem',kClaimed,id)
 			end
 			-- Get all of the dead jobs that have been marked as dead for too long.
 			-- The score for each item is the last claim timestamp (UNIX).
-			local deadClaims = redis.call('zRangeByScore',KEYS[5],0,ARGV[2])
+			local deadClaims = redis.call('zRangeByScore',kAbandoned,0,ARGV[2])
 			for k,id in ipairs(deadClaims) do
 				-- Stale and out of retries: remove any traces of the job
-				redis.call('zRem',KEYS[5],id)
-				redis.call('hDel',KEYS[2],id)
-				redis.call('hDel',KEYS[4],id)
+				redis.call('zRem',kAbandoned,id)
+				redis.call('hDel',kAttempts,id)
+				redis.call('hDel',kData,id)
 				pruned = pruned + 1
 			end
 			return {released,abandoned,pruned}
-- 
2.20.1