redis-mruby

A Redis module to evaluate mruby code.

Usage

Server:

$ redis-server --loadmodule build/redis-mruby.so

Client:

$ redis-cli
127.0.0.1:6379> mruby.eval "1 + 1"
(integer) 2

Command

mruby.eval script [[numkeys key1, key2, ...], [arg1, arg2, ...]]

Compatible to EVAL command that uses lua to execute code and is embedded into Redis by default. See https://redis.io/commands/eval for detail.

Embedded Arrays

You can access KEYS and ARGV passed via cli in mruby code.

127.0.0.1:6379> mruby.eval "[KEYS, ARGV]" 2 key1 key2 arg1 arg2
1) 1) "key1"
   2) "key2"
2) 1) "arg1"
   2) "arg2"

Type Conversion

The return value from mruby code is automatically converted to some form of Redis replies listed below:

mruby	redis
true	integer reply with value of 1 (integer)
false	nil bulk reply
Fixnum	integer reply
Float	bulk reply with the the value converted to string expression of equivalent double value
String	bulk reply
Array	multi bulk reply
Hash	multi bulk reply with an empty list
Object	multi bulk reply with an empty list
Exception	error reply

Below are several (not complete) examples of type conversion.

Integer

127.0.0.1:6379> mruby.eval "1 + 1"
(integer) 2

String

127.0.0.1:6379> mruby.eval "%q{hello}"
"hello"

Array

127.0.0.1:6379> mruby.eval "[1, 2, [3, 4, [5, 6]]]"
1) (integer) 1
2) (integer) 2
3) 1) (integer) 3
   2) (integer) 4
   3) 1) (integer) 5
      2) (integer) 6

Error

127.0.0.1:6379> mruby.eval "no_such_method"
(error) undefined method 'no_such_method' for main

Author

Kentaro Kuribayashi

License

MIT