util.openmetrics: Prettify format of histogram buckets "%g" turns 1GB into 1.07374e+09, which is a bit awkward for the bytes measurements IMO. Turning up the precision, at "%.17g" turns 0.1 into 0.10000000000000001 while "%0.16" gives 0.1, hiding most of those pesky floating point artefacts. Lua version 5.2 uses "%.14g" ( see LUA_NUMBER_FMT in luaconf.h.html ) so it seems like a sensible choice here.

--- a/util/openmetrics.lua	Mon Jun 07 17:37:14 2021 +0200
+++ b/util/openmetrics.lua	Tue Jun 08 00:58:27 2021 +0200
@@ -58,7 +58,7 @@
 		return "+Inf"
 	end
 
-	return string.format("%g", v)
+	return string.format("%.14g", v)
 end
 
 -- BEGIN of generic MetricFamily implementation