kong-propagation-timing-3.0.lua

local to_hex = require "resty.string".to_hex
local get_rand_bytes = require "kong.tools.utils".get_rand_bytes
local concat = table.concat

local proxy_span = {
  trace_id = get_rand_bytes(16),
  span_id = get_rand_bytes(8),
  parent_id = get_rand_bytes(8),
  should_sample = true,
}

local function target1()
  return to_hex(proxy_span.trace_id) ..
      "-" .. to_hex(proxy_span.span_id) ..
      "-" .. (proxy_span.should_sample and "1" or "0") ..
      (proxy_span.parent_id and "-" .. to_hex(proxy_span.parent_id) or "")
end

local function target2()
  return concat({
    to_hex(proxy_span.trace_id),
    to_hex(proxy_span.span_id),
    (proxy_span.should_sample and "1" or "0"),
    -- fine if parent_id is nil
    proxy_span.parent_id,
  }, "-")
end


local target = target2

for i = 1, 100 do
  target()
end
ngx.update_time()
local begin = ngx.now()
local N = 1e7
for i = 1, N do
  target()
end
ngx.update_time()
ngx.say("elapsed: ", (ngx.now() - begin) / N)