An introspective stats collector for Redis, in Redis

infospect.lua

-- infospect.lua - an introspective stats collector for Redis, in Redis
--
-- Each time you run this script, INFO lines are added to lists with
-- their respective names.
-- Suggested usage:
--   SCRIPT LOAD infospect.lua 
--   cron redis-cli EVALSHA <infospect-sha1> 

-- list of stat names/prefixes to collect
local collected_stats = 
  'cmdstat_,'..
  'connected_clients,'..
  'db0,'..
  'evicted_keys,'..
  'expired_keys,'..
  'instantaneous_ops_per_sec,'..
  'keyspace_hits,'..
  'keyspace_misses,'..
  'rejected_connections,'..
  'uptime_in_seconds,'..
  'used_memory,'

local samples_max = 100             -- the number of samples to keep
local samples_prefix = 'infospect'  -- the prefix for samples' keys

local function store(key, value)
  redis.call('lpush', key, value)
  redis.call('ltrim', key, 0, samples_max - 1)
end

local function collect(l)
  if l:len() > 0 then           -- ignore empty lines
    if l:sub(1,1) == '#' then   -- section line
      stats_section = l:match('# (.*)')
    else
      local name, value = l:match('([%a%d_]+):(.*)')
      local pre, post = name:match('([%a%d_]+)_(.*)')
      if (collected_stats:find(name) ~= nil or 
        (pre ~= nil and collected_stats:find(pre..'_') ~= nil)) then
        local key = samples_prefix..':'..stats_section..':'..name
        if value:find(',') == nil then
          store(key, value)
        else
          for n,v in value:gmatch('([%a%d_]*)=([%a%d_]*),?') do
            store(key..':'..n, v)
          end
        end
      end
    end
  end
  return ''
end

local stats_section = ''
local raw_info = redis.call('INFO', 'all')
collect(raw_info:gsub('(.-)\r?\n', collect))

return 'OK'

Won't work anymore, because INFO returns random stuff... unless used on Redis 3.2 + redis.replicate_commands()