1 local seq = 0

2 local saved_tree

3

4 request.for_each(function()

5 if seq == 0 then

6 -- prepare for configuration/initialization phase

7 trace._disabled = false

8 trace._tree = { type = "root", start_hires_time = extos.monotonic_hires_time() }

9 trace._stack = { trace._tree }

10 seq = 1

11 elseif seq == 1 then

12 -- save current state before processing first request

13 if not (trace._stack[1] == trace._tree and trace._stack[2] == nil) then

14 error("Trace stack unbalanced after initialization")

15 end

16 if not trace._disabled then

17 saved_tree = table.new(trace._tree)

18 end

19 seq = 2

20 elseif saved_tree then

21 -- restore state before processing next request

22 if saved_tree then

23 trace._disabled = false

24 trace._tree = table.new(saved_tree)

25 trace._stack = { trace._tree }

26 end

27 end

28 end)