perfermance test for kong old and new dns client library

perf.lua

--[[
run it by this command:

$ resty --shdict "kong_dns_cache 10m" --shdict "kong_dns_cache_ipc 10m" ./perf.lua

]]

pcall(require, "luarocks.loader")
require("kong.globalpatches")()
local json = require("cjson").encode

-- hosted in Route53 in the AWS sandbox
local TEST_NS = "192.168.1.1:53"
local TEST_NS = "192.168.5.2:53"  -- Kong local official env

local TEST_NSS = { TEST_NS }

local not_found_answers = { errcode = 3, errstr = "not found" }

local a_answers = {{ address = "127.0.0.1", class = 1, ttl = 300, type = 1 }}

-- inject r.query
package.loaded["resty.dns.resolver"] = nil
local resolver = require("resty.dns.resolver")
local query_func = function(self, original_query_func, name, options)
  return original_query_func(self, name, options)
end

local old_new = resolver.new
resolver.new = function(...)
  local r, err = old_new(...)
  if not r then
    return nil, err
  end
  local original_query_func = r.query
  r.query = function(self, ...)
    return query_func(self, original_query_func, ...)
  end
  return r
end
--- end of inject r.query

-- restore its API overlapped by the compatible layer
package.loaded["kong.resty.dns_client"] = nil
local client = require("kong.resty.dns_client")
client.resolve = client._resolve

--- TEST APIs
local t
local n

local function test(name, f)
  local new_delta, old_delta
  print(name)
  -- new
  local cli = assert(client.new({
    nameservers = TEST_NSS,
    order = { "LAST", "SRV", "A", "CNAME" },
  }))
  t = os.clock()
  f(function (host) return cli:resolve(host) end)
  new_delta = os.clock() - t
  print("NEW DNS client consumes: ", new_delta, " 1 try=", new_delta/n *1000, " ms")

  -- old
  package.loaded["kong.resty.dns.client"] = nil
  local cli = require("kong.resty.dns.client")
  assert(cli.init({
    resolvConf = { "nameserver " .. TEST_NS },
    order = { "LAST", "SRV", "A", "CNAME" },
  }))

  local t = os.clock()
  f(function (host) return cli.resolve(host) end)
  old_delta = os.clock() - t
  print("OLD DNS client consumes: ", old_delta, " 1 try=", old_delta/n *1000, " ms")

  -- last
  local improved = (n/new_delta)/(n/old_delta) - 1
  print(("Improved: %.2f%%\n"):format(improved * 100))
end

--- run test
print("\n\n\n\n\n--- runing perf test ---\n")

--- 100% Hit
n = 100000
local title = "+ hit 100% (miss the first time)"

test(tile, function (cli_resolve)
  local answers, err, tries
  answers, err, tries = cli_resolve("www.konghq.com")
  t = os.clock()  -- skip first miss
  for i = 1, n do
    answers, err, tries = cli_resolve("www.konghq.com")
  end
  assert(answers[1].name == "www.konghq.com")
end)


--- ?% Hit
--[[
local rate = 9999
local title = ("+ %s%% Hit (Every query to the nameserver succeeds.)"):format(rate)
local count = 0

query_func = function(self, original_query_func, name, options)
  count = count + 1
  if options.qtype == 33 then -- SRV
    return not_found_answers
  end
  a_answers[1].name = name
  return a_answers
  --return {{ address = "127.0.0.1", class = 1, ttl = 300, type = 1, name = name }}
end

test(title, function (cli_resolve)
  local answers, err, tries, host
  answers, err, tries = cli_resolve("www.konghq.com")
  t = os.clock()  -- skip first miss
  count = 0
  for i = 1, n do
    host = ((i % 10000) < rate) and "www.konghq.com" or i .. ".konghq.com"
    answers, err, tries = cli_resolve(host)
    --assert(answers[1].name == host)
  end
  print("  rate:", 1 - count / (2 * n))
  -- assert(count == 2 * n)
end)
]]

--- 0% Hit
n = 10000
local title = "+ 0% Hit (Every query to the nameserver succeeds.)"
local count = 0

query_func = function(self, original_query_func, name, options)
  count = count + 1
  if options.qtype == 33 then -- SRV
    return not_found_answers
  end
  a_answers[1].name = name
  return a_answers
end

test(title, function (cli_resolve)
  local answers, err, tries
  count = 0
  for i = 1, n do
    answers, err, tries = cli_resolve(i .. ".konghq.com")
  end
  assert(answers[1].name == n .. ".konghq.com")
  assert(count == 2 * n)
end)

1. My test branch kong-ce refactor/dns_client from this PR Kong/kong#12305
2. git checkout to this branch refactor/dns_client
3. Go into Bazel development env: . bazel-bin/build/kong-dev-venv.sh
4. Run it with the command: resty --shdict "kong_dns_cache 10m" --shdict "kong_dns_cache_ipc 10m" ./perf.lua

Result like :

(kong-dev) xc kong $ resty --shdict "kong_dns_cache 10m" --shdict "kong_dns_cache_ipc 10m" /Users/xc/work/snippets/openresty/dns_client_test/perf.lua 2>/dev/null

--- runing perf test ---

NEW DNS client consumes: 0.020167 1 try=0.00020167 ms
OLD DNS client consumes: 0.054615 1 try=0.00054615 ms
Improved: 170.81%

+ 0% Hit (Every query to the nameserver succeeds.)
NEW DNS client consumes: 0.886844 1 try=0.0886844 ms
OLD DNS client consumes: 0.708964 1 try=0.0708964 ms
Improved: -20.06%