From: Alex Tomlins <redacted>
Date: Wed, 3 Apr 2019 20:08:11 +0000 (+0100)
Subject: prometheus-node-exporter-lua: fix missing conntrack values
X-Git-Url: http://git.99rst.org/?a=commitdiff_plain;h=0100a2cb26c30ee091a259625b9496dd7805aaaa;p=openwrt-packages.git

prometheus-node-exporter-lua: fix missing conntrack values

If the /proc/sys/net/netfilter/nc_conntrack_* files are not present,
this exporter was outputting a blank value, which is invalid. These
files will not be present when using an image that doesn't include the
iptables and firewall packages (eg a minimal access-point type image).

This updates the collector to only output the metrics if the
corresponding /proc files are present.

Signed-off-by: Alex Tomlins <redacted>
---

diff --git a/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/conntrack.lua b/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/conntrack.lua
index 93b26c266..1abb7a191 100644
--- a/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/conntrack.lua
+++ b/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/conntrack.lua
@@ -1,8 +1,12 @@
 local function scrape()
-  metric("node_nf_conntrack_entries", "gauge", nil,
-    string.sub(get_contents("/proc/sys/net/netfilter/nf_conntrack_count"), 1, -2))
-  metric("node_nf_conntrack_entries_limit", "gauge", nil,
-    string.sub(get_contents("/proc/sys/net/netfilter/nf_conntrack_max"), 1, -2))
+  local count = get_contents("/proc/sys/net/netfilter/nf_conntrack_count")
+  local max = get_contents("/proc/sys/net/netfilter/nf_conntrack_max")
+  if count ~= "" then
+    metric("node_nf_conntrack_entries", "gauge", nil, string.sub(count, 1, -2))
+  end
+  if max ~= "" then
+    metric("node_nf_conntrack_entries_limit", "gauge", nil, string.sub(max, 1, -2))
+  end
 end
 
 return { scrape = scrape }