#!/usr/bin/env bash

log_msg() {
	echo -e "[ ${HOSTNAME} ] [ $(date -u +"%Y-%m-%dT%H:%M:%SZ") ] $*" >&2;
}


log_msg "Installing nomad";
sudo apt-get update;
sudo apt-get install --yes hashicorp-nomad;

log_msg "nomad installed successfully. Version:";
nomad --version;

log_msg "Creating directories";
if [[ ! -d "/etc/nomad" ]]; then
	sudo mkdir /etc/nomad;
	sudo chown root:root /etc/nomad;
fi

if [[ ! -d "/srv/nomad" ]]; then
	sudo mkdir /srv/nomad;
	sudo chown root:root /srv/nomad;
	sudo chmod 0750 /srv/nomad;
fi

check_cgroups_memory() {
	log_msg "Checking memory cgroups";
	
	cgroups_enabled="$(awk '/memory/ { print $2 }' < /proc/cgroups)";
	
	if [[ "${cgroups_enabled}" -ne 0 ]]; then
		log_msg "memory cgroups already enabled";
		return 0;
	fi
	
	
	filepath_cmdline="/boot/cmdline.txt";
	if [[ ! -e "${filepath_cmdline}" ]]; then
		filepath_cmdline="/boot/firmware/cmdline.txt";
	fi
	if [[ ! -e "${filepath_cmdline}" ]]; then
		log_msg "Failed to find cmdline.txt; can't check for cgroups";
		return 1;
	fi
	
	if grep -q cgroup_enable=memory /boot/cmdline.txt; then
		log_msg "memory cgroups already present in cmdline.txt, a reboot is required to apply the update";
		return 0;
	fi
	
	log_msg "memory cgroups not present in cmdline.txt, enabling....";
	(tr -d '\n' <"${filepath_cmdline}" && echo " cgroup_enable=memory cgroup_memory=1") | sudo tee "${filepath_cmdline}.new";
	
	sudo mv "${filepath_cmdline}" "${filepath_cmdline}.old-$(date +"%Y-%m-%d")";
	sudo mv "${filepath_cmdline}.new" "${filepath_cmdline}";
	
	log_msg "New contents of cmdline.txt:";
	cat "${filepath_cmdline}";
	log_msg "A reboot is required to apply the changes.";
}

check_cgroups_memory;