Linux Server Health Monitor (Fyrehose/FnordMetric)

server_monitor.sh

#!/bin/bash

# This scripts sends a JSON message containing system health
# information to a fyrehose channel.
#
# Usage:
#   $ ./linux_health_monitor.sh [host] [port] [channel]
# e.g.
#   $ ./linux_health_monitor.sh localhost 2323 my_channel
#
# The JSON body will look like this:
# {
#   "hostname": "my-hostname",
#   "uptime": 1231523,
#   "load_avg": [0.32, 0.16, 0.13],
#   "mem": { "total": 4069, "free": 1096 },
#   "swap": { "total": 0, "free": 0 },
#   "disk_usage": "43%"
# }

if [[ $# -ne 3 ]]; then
  echo "usage: $0 [host] [port] [channel]"
  exit 1
fi

for cmd in df wc nc sed grep; do
  which $cmd &> /dev/null

  if [ $? != 0 ]; then
    echo "error: command not found: $cmd"
    exit 1
  fi
done

data=$(

  # hostname
  echo "\"hostname\": \"$(hostname)\","

  # uptime
  cat /proc/uptime | \
    sed -e 's/^\([0-9]\+\.[0-9]\+\).*/"uptime": \1,/'

  # load_avg
  cat /proc/loadavg | \
    sed -e 's/^\([0-9]\+\.[0-9]\+\) \([0-9]\+\.[0-9]\+\) \([0-9]\+\.[0-9]\+\).*/"load_avg": [\1, \2, \3],/'

  # mem usage
  cat /proc/meminfo | \
    grep -E '^(MemTotal|MemFree)' | \
    sed -e 's/Mem//' -e 's/Total:[^0-9]\+\([0-9]\+\).*/"mem": { "total": \1,/' \
        -e 's/Free:[^0-9]\+\([0-9]\+\).*/"free": \1 },/'

  # swap_usage
  cat /proc/meminfo | \
    grep -E '^(SwapTotal|SwapFree)' | \
    sed -e 's/Swap//' -e 's/Total:[^0-9]\+\([0-9]\+\).*/"swap": { "total": \1,/' \
        -e 's/Free:[^0-9]\+\([0-9]\+\).*/"free": \1 },/'

  # disk usage
    df | grep -E '\/$' | \
      sed -e 's/.* \([0-9]\+%\) .*/"disk_usage": "\1"/'

)

evt=$(echo "{ $data }" | sed -e ':x;N;$!bx;s/\n/ /g')
evt_len=$(echo -n $evt | wc -c)

(echo -n "#0 @$3 "'*'"$evt_len "; echo $evt) | \
  nc $1 $2 > /dev/null

exit $?