collect-ps-periodically

#!/usr/bin/env bash
# Collects the output of 'ps' periodically, and dumps them to
# the given directory, with one file per dump.
#
# ## Usage syntax
#
#     collect-ps-periodically <DUMP DIRECTORY> <INTERVAL>
#
# `DUMP DIRECTORY` specifies where to dump to. This directory must
# already exist.
#
# `INTERVAL` specifies the interval between dumps, in seconds. You
# can also specify a unit suffix, e.g. `5m` (5 minutes) or `2h` (2 hours).
#
# ## Example
#
# Create a dump directory and run the script in the background,
# collecting every 5 minutes:
#
#     mkdir ~/ps-dumps
#     nohup collect-ps-periodically ~/ps-dumps 5m &
#
# At any point, feel free to stop the script...
#
#     ps aux | grep collect-ps-periodically
#     kill <PID>
#
# ...and tar the dump directory and send it to someone for analysis:
#
#     tar -czf ps-dumps.tar.gz ~/ps-dumps

set -e

TARGET_DIR="$1"
INTERVAL="$2"
if [[ -z "$TARGET_DIR" || -z "$INTERVAL" ]]; then
	echo 'Usage: collect-ps-periodically <DUMP DIRECTORY> <INTERVAL>'
	exit 1
fi

function cleanup()
{
	# shellcheck disable=SC2155
	local PIDS=$(jobs -p)
	if [[ -n "$PIDS" ]]; then
		# shellcheck disable=SC2086
		kill $PIDS || true
	fi
}

trap cleanup EXIT

while true; do
	DATE=$(date --rfc-3339=seconds)
	ps -Ao 'user,pid,ppid,lwp,%cpu,%mem,rss,maj_flt,start_time,wchan,stat,flag,nlwp,cmd' --forest > "$TARGET_DIR/$DATE procs.txt"
	ps -ALo 'user,pid,ppid,lwp,%cpu,%mem,rss,maj_flt,start_time,wchan,stat,flag,cmd' > "$TARGET_DIR/$DATE threads.txt"
	sleep "$INTERVAL"
done