# lib/prometheus
# Functions to control the installation and configuration of prometheus

# Save trace setting
_XTRACE_PROMETHEUS=$(set +o | grep xtrace)
set +o xtrace

PROMETHEUS_SYSTEMD_SERVICE="devstack@prometheus.service"
PROMETHEUS_DATA_DIRECTORY="/var/lib/prometheus"
PROMETHEUS_PORT=${PROMETHEUS_PORT:-9090}

function pre_install_prometheus {
    # Install OS packages
    install_package wget tar jq
}

function install_prometheus {

    local prom_tarball=prometheus-${PROMETHEUS_VERSION}.linux-amd64.tar.gz
    local prom_url=https://github.com/prometheus/prometheus/releases/download/v${PROMETHEUS_VERSION}/${prom_tarball}

    # Download Prometheus
    local prom_dest
    prom_dest=`get_extra_file ${prom_url}`

    # Extract the tarball
    tar xzf ${prom_dest} -C $DEST

    # Move binaries to /usr/local/bin
    sudo mv $DEST/prometheus-${PROMETHEUS_VERSION}.linux-amd64/prometheus /usr/local/bin/
    sudo mv $DEST/prometheus-${PROMETHEUS_VERSION}.linux-amd64/promtool /usr/local/bin/

    # Set ownership
    sudo chown $(whoami):$(whoami) /usr/local/bin/prometheus
    sudo chown $(whoami):$(whoami) /usr/local/bin/promtool
}

function configure_prometheus {
    # Configure prometheus
    sudo mkdir /etc/prometheus
    sudo chown $(whoami):$(whoami) /etc/prometheus

    # Copy User's prometheus config
    sudo cp ${PROMETHEUS_CONFIG_FILE} /etc/prometheus

    # Change the permission of prometheus config
    sudo chmod 0644 /etc/prometheus/$(basename ${PROMETHEUS_CONFIG_FILE})

    # Show User's prometheus config
    sudo cat /etc/prometheus/$(basename ${PROMETHEUS_CONFIG_FILE})

    # Create data directory
    sudo mkdir ${PROMETHEUS_DATA_DIRECTORY}
    sudo chown $(whoami):$(whoami) ${PROMETHEUS_DATA_DIRECTORY}
}

function init_prometheus {
    prometheus_command="/usr/local/bin/prometheus"
    prometheus_command+=" --config.file=/etc/prometheus/prometheus.yml"
    prometheus_command+=" --storage.tsdb.path=${PROMETHEUS_DATA_DIRECTORY}"
    prometheus_command+=" --web.enable-admin-api"
    prometheus_command+=" --web.enable-remote-write-receiver"

    write_user_unit_file $PROMETHEUS_SYSTEMD_SERVICE "$prometheus_command" "" "$STACK_USER"

    enable_service $PROMETHEUS_SYSTEMD_SERVICE
}

function start_prometheus {
    start_service $PROMETHEUS_SYSTEMD_SERVICE
}

function stop_prometheus {
    stop_service $PROMETHEUS_SYSTEMD_SERVICE
}

function cleanup_prometheus {

    stop_prometheus

    disable_service $PROMETHEUS_SYSTEMD_SERVICE

    # Remove systemd unit files
    local unitfile="$SYSTEMD_DIR/$PROMETHEUS_SYSTEMD_SERVICE"
    sudo rm -f $unitfile
    $SYSTEMCTL daemon-reload

    # Remove Prometheus directories
    sudo rm -rf /etc/prometheus
    sudo rm -rf ${PROMETHEUS_DATA_DIRECTORY}

    # Remove binaries
    sudo rm /usr/local/bin/prometheus
    sudo rm /usr/local/bin/promtool

    # Remove untar location
    sudo rm -rf $DEST/prometheus-${PROMETHEUS_VERSION}.linux-amd64
}

function wait_for_data {
    # Adding sleep time so that data is scrapped by prometheus
    sleep 60
}

function check_data_prometheus {
    local url="http://$HOST_IP:$PROMETHEUS_PORT/api/v1/label/__name__/values"

    if curl -s --head  --request  GET "$url" | grep "200 OK" > /dev/null; then
        echo "#### List of metrics names ####"
        curl -s "$url" | jq -r '.data[]'
    else
        die $LINENO "Couldn't get data from prometheus"
    fi
}

# Restore xtrace
$_XTRACE_PROMETHEUS