feat: add a surface to support Redis module

[spacewander]

No description provided.

[doujiang24]

bad indent.

[spacewander]

@doujiang24
Fixed.

[doujiang24]

Suggested change

	self._module_prefix = mod .. "."
	self._module_prefix = mod

move the .. "." to line 414: https://github.com/openresty/lua-resty-redis/pull/211/files#diff-adb515948c05651051c83fd6fb3ce7ceR414
to avoid creating a new string for better performance.

[spacewander]

@doujiang24
There will be more new strings, as each time the cmd argument need to be a concatenated string in line 414.

[doujiang24]

@spacewander I don't think so.
it will generate a new string when calling the module function, like redis:bp().
and generate another string when calling the method, like :add().

that means will generate two string in redis:bp:add().

while module_prefix .. "." .. cmd will generate one string.

[doujiang24]

I think this way may have better performance, thoughts?

local dot_cmds = {
    "bf.add", "bf.exists",
}

for i = 1, #dot_cmds do
    local cmd = dot_cmds[i]
    local name = string.gsub(cmd, ".", "_")

    _M[name] =
        function (self, ...)
            return _do_cmd(self, cmd, ...)
        end
end

[doujiang24]

@spacewander I don't think so.
it will generate a new string when calling the module function, like redis:bp().
and generate another string when calling the method, like :add().

that means will generate two string in redis:bp:add().

while module_prefix .. "." .. cmd will generate one string.

[spacewander]

I think this way may have better performance, thoughts?

local dot_cmds = {
    "bf.add", "bf.exists",
}

for i = 1, #dot_cmds do
    local cmd = dot_cmds[i]
    local name = string.gsub(cmd, ".", "_")

    _M[name] =
        function (self, ...)
            return _do_cmd(self, cmd, ...)
        end
end

OK, maybe we can just a much simpler solution like https://github.com/openresty/lua-resty-redis/pull/167/files

[doujiang24]

OK, maybe we can just a much simpler solution like https://github.com/openresty/lua-resty-redis/pull/167/files

it has two issues:

1. need a string.gsub call per redis method call.
2. some redis command may contains _, like SORT_RO: https://redis.io/commands/sort_ro

[doujiang24]

I like the new module function call style: redis:bf():add().