system-metrics-collector

#!/bin/sh

#
# Simple log system metrics collector. Polls the system state every 30s and
# saves the result to /tmp/system-metrics.
#
# The simple nature of the script allows it to seemlesly run in any Linux based
# VM, Docker image, or on a MacVM host.
#
# The recommended way to start the script is to run it in the background.
#
#   $ system-metrics-collector &
#
# The resulting file's format is the following:
#
#   $ cat /tmp/system-metrics-collector
#
#     Mon May 18 14:50:58 UTC 2020 | mem:   5.03%, disk:  47.75%
#     Mon May 18 14:51:28 UTC 2020 | mem:   5.03%, disk:  47.75%
#
# Jobs that run for an hour collect around 120 log lines. This should be safe
# and not introduce any performance of disk usage problems.
#

SYSTEM_DISK_LOCATION="/"
DOCKER_DISK_LOCATION="/$([ -d /var/lib/docker ] && echo 'var/lib/docker')"
OUTPUT="/tmp/system-metrics"

while true; do
  MEMORY=$(free | grep Mem | awk '{ printf("%6.2f%%\n", ($3/$2 * 100.0)) }')
  SHARED_MEMORY=$(free -m | grep Mem | awk '{ print $5 }')
  SYSTEM_DISK=$(df "$SYSTEM_DISK_LOCATION" | sed 1d | awk '{ printf("%6.2f%%\n", ($3/$2 * 100.0)) }')
  DOCKER_DISK=$(df "$DOCKER_DISK_LOCATION" | sed 1d | awk '{ printf("%6.2f%%\n", ($3/$2 * 100.0)) }')
  echo "$(date) | mem:$MEMORY,  system_disk:$SYSTEM_DISK,  docker_disk:$DOCKER_DISK,  shared_memory: $SHARED_MEMORY M" >> $OUTPUT
  sleep 1
done