From 760332a8e4eadfbbcc80fec4601de6dc62609068 Mon Sep 17 00:00:00 2001
From: Joshua Kahn <jkahn@barracuda.com>
Date: Fri, 7 Jun 2019 10:12:09 -0400
Subject: [PATCH] Fix errant keys in Redis scripts

The metric labels and command types were inappropriately specified as
KEYS in the Redis scripts. This meant there was no way to avoid a
`CROSSSLOT Keys in request don't hash to the same slot` error when using
a Redis cluster that hashes keys to select a specific node.
---
 src/Prometheus/Storage/Redis.php | 44 ++++++++++++++++----------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index f38391b..9f25fe6 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -117,23 +117,23 @@ public function updateHistogram(array $data)
         unset($metaData['value']);
         unset($metaData['labelValues']);
         $this->redis->eval(<<<LUA
-local increment = redis.call('hIncrByFloat', KEYS[1], KEYS[2], ARGV[1])
-redis.call('hIncrBy', KEYS[1], KEYS[3], 1)
-if increment == ARGV[1] then
-    redis.call('hSet', KEYS[1], '__meta', ARGV[2])
-    redis.call('sAdd', KEYS[4], KEYS[1])
+local increment = redis.call('hIncrByFloat', KEYS[1], ARGV[1], ARGV[3])
+redis.call('hIncrBy', KEYS[1], ARGV[2], 1)
+if increment == ARGV[3] then
+    redis.call('hSet', KEYS[1], '__meta', ARGV[4])
+    redis.call('sAdd', KEYS[2], KEYS[1])
 end
 LUA
             ,
             array(
                 $this->toMetricKey($data),
+                self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
                 json_encode(array('b' => 'sum', 'labelValues' => $data['labelValues'])),
                 json_encode(array('b' => $bucketToIncrease, 'labelValues' => $data['labelValues'])),
-                self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
                 $data['value'],
                 json_encode($metaData),
             ),
-            4
+            2
         );
     }
 
@@ -145,30 +145,30 @@ public function updateGauge(array $data)
         unset($metaData['labelValues']);
         unset($metaData['command']);
         $this->redis->eval(<<<LUA
-local result = redis.call(KEYS[2], KEYS[1], KEYS[4], ARGV[1])
+local result = redis.call(ARGV[1], KEYS[1], ARGV[2], ARGV[3])
 
-if KEYS[2] == 'hSet' then
+if ARGV[1] == 'hSet' then
     if result == 1 then
-        redis.call('hSet', KEYS[1], '__meta', ARGV[2])
-        redis.call('sAdd', KEYS[3], KEYS[1])
+        redis.call('hSet', KEYS[1], '__meta', ARGV[4])
+        redis.call('sAdd', KEYS[2], KEYS[1])
     end
 else
-    if result == ARGV[1] then
-        redis.call('hSet', KEYS[1], '__meta', ARGV[2])
-        redis.call('sAdd', KEYS[3], KEYS[1])
+    if result == ARGV[3] then
+        redis.call('hSet', KEYS[1], '__meta', ARGV[4])
+        redis.call('sAdd', KEYS[2], KEYS[1])
     end
 end
 LUA
             ,
             array(
                 $this->toMetricKey($data),
-                $this->getRedisCommand($data['command']),
                 self::$prefix . Gauge::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
+                $this->getRedisCommand($data['command']),
                 json_encode($data['labelValues']),
                 $data['value'],
                 json_encode($metaData),
             ),
-            4
+            2
         );
     }
 
@@ -180,23 +180,23 @@ public function updateCounter(array $data)
         unset($metaData['labelValues']);
         unset($metaData['command']);
         $result = $this->redis->eval(<<<LUA
-local result = redis.call(KEYS[2], KEYS[1], KEYS[4], ARGV[1])
-if result == tonumber(ARGV[1]) then
-    redis.call('hMSet', KEYS[1], '__meta', ARGV[2])
-    redis.call('sAdd', KEYS[3], KEYS[1])
+local result = redis.call(ARGV[1], KEYS[1], ARGV[2], ARGV[3])
+if result == tonumber(ARGV[3]) then
+    redis.call('hMSet', KEYS[1], '__meta', ARGV[4])
+    redis.call('sAdd', KEYS[2], KEYS[1])
 end
 return result
 LUA
             ,
             array(
                 $this->toMetricKey($data),
-                $this->getRedisCommand($data['command']),
                 self::$prefix . Counter::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
+                $this->getRedisCommand($data['command']),
                 json_encode($data['labelValues']),
                 $data['value'],
                 json_encode($metaData),
             ),
-            4
+            2
         );
         return $result;
     }