support nonblocking behavior.

[littleboss]

i check the lua redis client in https://github.com/agentzh/lua-resty-redis, it support 100% nonblocking behavior. because it uses cosocket api,

dose this client api support non blocking

thanks

[nrk]

Hi @littleboss,

This is a blocking client implementation and currently there are no plans to add a non-blocking interface to it (to be honest I've never experimented with cosocket) as it's not a priority. Things may change in this respect with help coming from other developers though.

[AMD-NICK]

You can make a non-blocking (asynchronous) implementation using copas. It will look like this ( example with benchmark):

local redis  = require("redis")
local copas  = require("copas")
local socket = require("socket")

local get_connection = function(host, port, pass)
	local sock = socket.tcp()
	sock = copas.wrap(sock)
	sock:connect(host, port or 6379)

	local client = redis.connect({
		socket = sock,
	})
	client:auth(pass)
	return client
end

local now = socket.gettime
local start = now()
local reps = 1000
for i = 1, reps do

	copas.addthread(function()
		local host, port, pass = "redis", 6379, "redis-pass"
		local client = get_connection(host, port, pass)

		print(i, client:incr("bench") )
		reps = reps - 1
		if reps == 0 then
			print("finished in " .. (now() - start) .. " seconds") -- 0.18 seconds for 1000 requests
		end
	end)
end

copas.loop()

⚠️ Yes, we making a new connection for every request, but you always can implement connection pool with copas.queue and copas.semaphore like I done it here: click, so you will not have to create new connections for every request

Here is the benchmark for the default implementation:

local redis = require("redis")

local host, port, pass = "redis", 6379, "redis_pass"

local client = redis.connect(host, port or 6379)
client:auth(pass)

local now = require("socket").gettime
local start = now()
for _ = 1, 1000 do
	print( client:incr("bench1") )
end
print("finished in " .. (now() - start) .. " seconds") -- 11.95 seconds

As you can see, 1000 queries in the synchronous implementation are executed in 11 seconds, while "async" queries are executed in 0.18 seconds