prometheus-node-exporter-lua: Added entropy.lua.

Signed-off-by: Jonathan Davies <jpds@protonmail.com>

utils/prometheus-node-exporter-lua/Makefile

@@ -4,7 +4,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=prometheus-node-exporter-lua
-PKG_VERSION:=2021.10.31
+PKG_VERSION:=2021.12.21
 PKG_RELEASE:=1
 
 PKG_MAINTAINER:=Etienne CHAMPETIER <champetier.etienne@gmail.com>
@@ -36,6 +36,7 @@ define Package/prometheus-node-exporter-lua/install
 	$(INSTALL_DIR) $(1)/usr/lib/lua/prometheus-collectors
 	$(INSTALL_BIN) ./files/usr/lib/lua/prometheus-collectors/cpu.lua         $(1)/usr/lib/lua/prometheus-collectors/
 	$(INSTALL_BIN) ./files/usr/lib/lua/prometheus-collectors/conntrack.lua   $(1)/usr/lib/lua/prometheus-collectors/
+	$(INSTALL_BIN) ./files/usr/lib/lua/prometheus-collectors/entropy.lua     $(1)/usr/lib/lua/prometheus-collectors/
 	$(INSTALL_BIN) ./files/usr/lib/lua/prometheus-collectors/filefd.lua      $(1)/usr/lib/lua/prometheus-collectors/
 	$(INSTALL_BIN) ./files/usr/lib/lua/prometheus-collectors/loadavg.lua     $(1)/usr/lib/lua/prometheus-collectors/
 	$(INSTALL_BIN) ./files/usr/lib/lua/prometheus-collectors/meminfo.lua     $(1)/usr/lib/lua/prometheus-collectors/

utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/entropy.lua

@@ -0,0 +1,9 @@
+local function scrape()
+  local available_bits = get_contents("/proc/sys/kernel/random/entropy_avail")
+  local pool_size_bits = get_contents("/proc/sys/kernel/random/poolsize")
+
+  metric("node_entropy_available_bits", "gauge", nil, available_bits)
+  metric("node_entropy_pool_size_bits", "gauge", nil, pool_size_bits)
+end
+
+return { scrape = scrape }