GENERIC_NGINX_CHECK uses ssh ControlMaster to share connections and save handshakes

script/monitor/checks/GENERIC_NGINX_CHECK.sh

@@ -1,14 +1,62 @@
 #!/bin/bash
 
-_SERVER="${1:?"FQDN of server missing"}"
-_PORT="${2:-"22"}"
-_USER="monitoring"
+_REMOTE_HOST="${1:?"FQDN of server missing"}"
+_REMOTE_PORT="${2:-"22"}"
+_REMOTE_USER="monitoring"
+_SOCKET='~/.ssh/%r@%h:%p'
+
+
+
+function checkViaHTTP() {
+    _STATUS="$(curl -I http://${_REMOTE_HOST} 2>/dev/null | head -n 1 | cut -d$' ' -f2)"
+    [ "${_STATUS}" == "200" ] \
+        && echo "OK" \
+        && return 0
+
+    return 1
+}
+
+function checkViaHTTPS() {
+    _STATUS="$(curl -k -I https://${_REMOTE_HOST} 2>/dev/null | head -n 1 | cut -d$' ' -f2)"
+    [ "${_STATUS}" == "200" ] \
+        && echo "OK" \
+        && return 0
+
+    return 1
+}
+
+function checkOrStartSSHMaster() {
+    timeout --preserve-status 1 "ssh -O check -S ${_SOCKET} ${_REMOTE_USER}@${_REMOTE_HOST}" &> /dev/null \
+        && return 0
+
+    ssh -O stop -S ${_SOCKET} ${_REMOTE_USER}@${_REMOTE_HOST} &> /dev/null
+    ssh -o ControlMaster=auto \
+        -o ControlPath=${_SOCKET} \
+        -o ControlPersist=65 \
+        -p ${_REMOTE_PORT} \
+        -f ${_REMOTE_USER}@${_REMOTE_HOST} exit &> /dev/null \
+        && return 0
+
+    echo "Fail: checkOrStartMaster()"
+    return 1
+}
 
 #grep:
-# -F                         Use fixed text, no regexp which has to be interpreted
+# -E                         Use regexp, '.*' => any chars between 'Active:' and '(running)', the round brackets are escaped.
 
 #cut:
 # -d                         Delimiter, marker where to cut (here ;)
 # -f                         Index of column to show (One based, so there is no -f0)
-_RESULT="$(ssh -p "${_PORT}" "${_USER}"@"${_SERVER}" 'systemctl status nginx.service' | grep -F Active: | grep -F running | cut -d';' -f2)"
-! [ -z "${_RESULT}" ] && echo "OK#UPTIME:${_RESULT}" || echo "FAIL"
+function checkViaSSH() {
+    checkOrStartSSHMaster \
+        || return 1
+
+    _RESULT=$(ssh -S ${_SOCKET} ${_REMOTE_USER}@${_REMOTE_HOST} 'systemctl status nginx.service' | grep -E 'Active:.*\(running\)' | cut -d';' -f2)
+    ! [ -z "${_RESULT}" ] && echo "INFO#UPTIME:${_RESULT}" || echo "FAIL"
+}
+
+#checkViaHTTP && exit 0
+#checkViaHTTPS && exit 0
+checkViaSSH && exit 0
+
+exit 1