What is the problem?
Accessing redis keys, which contains a hash object, through lua scripting actually returns a array instead of a hash.
Question
What is the best time efficient way to solve this issue?
- Save the value as a ruby's hash in form of string and than use eval to transform it
- Split that hash into multiple gets, each with a single value
- Save the value as a json object in form of string and than use oj gem to load it
Issue Details
HMSET
HMSET "[1, 79, 29, 44]" 0 1
Redis-rb gem
When accessing the key with redis gem, as expected, it returns a hash
2.1.3 :001 > require "redis"
require => true
2.1.3 :002 > r = Redis.new
=> #<Redis client v3.2.1 for redis://127.0.0.1:6379/0>
2.1.3 :003 > r.hgetall("[1, 79, 29, 44]")
=> {"0"=>"1"}
2.1.3 :004 >
Wolverine gem
When accessing the very same key through lua script (hmget.lua) using wolverine it actually returns an array
[1] pry(#<CubosController>)> a = MessagePack.unpack(Wolverine.hmget(["[1, 79, 29, 44]"]))
=> {"[1, 79, 29, 44]"=>["0", "1"]}
[2] pry(#<CubosController>)> a["[1, 79, 29, 44]"].class
=> Array
Redis-db-scripting gem
Has the same problem:
2.1.3 :005 > redis = Redis.new()
=> #<Redis client v3.2.1 for redis://127.0.0.1:6379/0>
2.1.3 :006 > scripts = Redis::Scripting::Module.new(redis,"/Users/rapha/projetos/qlikview/app/wolverine")
=> <Redis::Scripting::Module: 0x3fd69c62aec8 @source_dir="/Users/rapha/projetos/qlikview/app/wolverine" @redis=# <Redis:0x007fad39571730>>
2.1.3 :007 > MessagePack.unpack(scripts.run(:hmget, ["[1, 79, 29, 44]"], []))
=> {"[1, 79, 29, 44]"=>["0", "1"]}
hmget.lua
local data = {}
for _, key in ipairs(KEYS) do
data[key] = redis.call('HGETALL', key)
end
return cmsgpack.pack(data)
The messagePack compress/decompress is not the issue, already tested that.
Issue opened in Wolverine
https://github.com/Shopify/wolverine/issues/13
Similar issues already fixed
