start glances, single instance, user glances

glances-start.sh

#!/usr/bin/env bash
#
# run single instance of glances on the system as user glances.
# follows from https://gist.github.com/jtmoon79/1b5a806b3e71874542c21b1578156a42
# designed for a Debian-based Linux
#
# place this file at /var/lib/glances/glances-start.sh
#     chmod +x /var/lib/glances/glances-start.sh
# should look like:
#     ls -l /var/lib/glances/glances-start.sh
#     -rwxr-xr-x 1 root root 620 Jul 14 11:40 /var/lib/glances/glances-start.sh
#

set -e
set -u

if [ "$(whoami)" != "glances" ]; then
    set -x
    exec sudo -u glances -- "${0}" "${@}"
fi

if pgrep --exact glances &>/dev/null; then
    pkill --echo glances
fi

export VENV_GLANCES="/var/lib/glances/.venv-glances"
if [[ ! -d "${VENV_GLANCES}" ]]; then
    echo "Virtual Environment path not found '${VENV_GLANCES}'" >&2
    exit 1
fi
set +u
source "${VENV_GLANCES}/bin/activate"
set -u
python --version
glances --version
set -x
# XXX: glances does not seem to output anything if stdout/stderr are redirected to a file
glances \
    --webserver \
    --debug \
    --diskio-show-ramfs \
    --diskio-iops \
    --fs-free-space \
    --byte \
    --enable-process-extended \
    &>/var/lib/glances/glances.log &