From c521d9eb71c9ca96348598d20eecb5ffd746aabf Mon Sep 17 00:00:00 2001 From: "Danilo M." Date: Thu, 17 Sep 2026 19:04:34 +0200 Subject: feat: add a byte-rate counter for interface statistics Mirrors new_cpu_counter: cumulative counters need two samples to yield a rate, and each direction carries its own previous reading. Clamps a negative delta to zero rather than letting a 32-bit wrap or an interface reset produce a spike. One bogus sample sets the shared autoscale and flattens the entire window. Co-Authored-By: Claude Sonnet 5 --- test/test_data.lua | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'test') diff --git a/test/test_data.lua b/test/test_data.lua index 4d3280c..478bf78 100644 --- a/test/test_data.lua +++ b/test/test_data.lua @@ -178,4 +178,35 @@ assert(cut == string.rep('\u{00E9}', 9) .. '\u{2026}', assert(card.truncate(nil, 10) == '', 'nil truncates to empty') assert(card.truncate('abc', 0) == '', 'a zero limit gives empty') +-- === Network rate ========================================================= +-- Interface byte counters are cumulative, so a rate is a delta over elapsed +-- time. The first call has no previous sample and must report nil: any number +-- it invented would be wrong, and a spike at startup looks real. +local r = data.new_rate_counter() +assert(r:sample(1000, 100) == nil, 'first sample must give nil') + +-- 2048 bytes over 2 seconds is 1024 B/s. +local rate = r:sample(3048, 102) +assert(rate == 1024, 'second sample, got ' .. tostring(rate)) + +-- A counter that went backwards means a wrap or an interface reset. It must +-- clamp to zero, never produce the huge positive an unsigned wrap implies: +-- one bogus sample poisons the shared autoscale for the whole window. +local r2 = data.new_rate_counter() +r2:sample(5000, 100) +assert(r2:sample(10, 102) == 0, 'a counter reset must give 0') + +-- Two samples inside the same clock second. os.time() has whole-second +-- resolution against a 2s draw interval, so this happens in normal operation +-- and must not divide by zero. +local r3 = data.new_rate_counter() +r3:sample(1000, 500) +local same_second = r3:sample(2000, 500) +assert(same_second ~= nil and same_second >= 0, + 'a zero time delta must fall back to the draw interval, got ' .. tostring(same_second)) + +-- A missing interface reads nil, which must propagate rather than raise. +local r4 = data.new_rate_counter() +assert(r4:sample(nil, 100) == nil, 'a nil byte count gives nil') + print('test_data: all assertions passed') -- cgit v1.2.3