Merge ~paulgear/charm-nrpe/+git/nrpe-charm:master into ~nrpe-charmers/charm-nrpe:master

[Paul Gear]

Tentative (untested) fix for https://bugs.launchpad.net/nrpe-charm/+bug/1673064

[Haw Loeung (hloeung)]

LGTM, +1

review: Approve

[Haw Loeung (hloeung)]

LGTM, +1

review: Approve

diff --git a/files/plugins/check_conntrack.sh b/files/plugins/check_conntrack.sh
index 0cfaf28..1f08075 100755
--- a/files/plugins/check_conntrack.sh
+++ b/files/plugins/check_conntrack.sh
@@ -20,8 +20,16 @@ if ! lsmod | grep -q conntrack; then
     exit $STATE_OK
 fi
 
-max=$(sysctl net.netfilter.nf_conntrack_max | awk '{ print $3 }')
-current=$(sysctl net.netfilter.nf_conntrack_count | awk '{ print $3 }')
+max=$(sysctl net.netfilter.nf_conntrack_max 2>/dev/null | awk '{ print $3 }')
+if [ -z "$max" ]; then
+    echo "UNKNOWN: unable to retrieve value of net.netfilter.nf_conntrack_max"
+    exit $STATE_UNKNOWN
+fi
+current=$(sysctl net.netfilter.nf_conntrack_count 2>/dev/null | awk '{ print $3 }')
+if [ -z "$current" ]; then
+    echo "UNKNOWN: unable to retrieve value of net.netfilter.nf_conntrack_count"
+    exit $STATE_UNKNOWN
+fi
 
 # default thresholds
 crit=90
diff --git a/hooks/nrpe_helpers.py b/hooks/nrpe_helpers.py
index 90a6f8e..d96b0a8 100644
--- a/hooks/nrpe_helpers.py
+++ b/hooks/nrpe_helpers.py
@@ -250,11 +250,11 @@ class SubordinateCheckDefinitions(dict):
 
         if hookenv.config('load') == 'auto':
             # Give 1min load alerts higher thresholds than 15 min load alerts
-            warn_multipliers = (4,2,1)
-            crit_multipliers = (8,4,2)
+            warn_multipliers = (4, 2, 1)
+            crit_multipliers = (8, 4, 2)
             load_thresholds = ('-w %s -c %s') \
-                % (','.join([str(m*procs) for m in warn_multipliers]),
-                   ','.join([str(m*procs) for m in crit_multipliers]))
+                % (','.join([str(m * procs) for m in warn_multipliers]),
+                   ','.join([str(m * procs) for m in crit_multipliers]))
         else:
             load_thresholds = hookenv.config('load')
 
@@ -313,6 +313,8 @@ class SubordinateCheckDefinitions(dict):
         self['checks'] = []
         sub_postfix = str(hookenv.config("sub_postfix"))
         for check in checks:
+            if check['cmd_params'] == "":
+                continue
             check['description'] += " (sub)"
             check['cmd_name'] += sub_postfix
             self['checks'].append(check)