`machine`, `apps`, `devenv`; `service ...`-command(s) to control user service

[gbraad]

• service install/export
• service start|stop
• service enable|disable
• service status
• service remove
• service ...

If a service file exists, starting will be controlled by the service instead.

• uses userctl.

[gbraad]

Monitoring

monitor_systemd_percent_mem() {
    local SERVICE="$1"
    if [[ -z "$SERVICE" ]]; then
        echo "Usage: monitor_systemd_percent_mem <service-name>"
        return 1
    fi

    local CORES=$(nproc)
    local PREV_CPU=$(systemctl show --user "$SERVICE" --property=CPUUsageNSec | awk -F= '{print $2}')
    local PREV_MEM=$(systemctl show --user "$SERVICE" --property=MemoryCurrent | awk -F= '{print $2}')
    local PREV_TIME=$(date +%s%N)

    if [[ -z "$PREV_CPU" || -z "$PREV_MEM" ]]; then
        echo "Could not read CPUUsageNSec or MemoryCurrent for $SERVICE. Is the service running?"
        return 1
    fi

    while true; do
        sleep 2
        local CURR_CPU=$(systemctl show --user "$SERVICE" --property=CPUUsageNSec | awk -F= '{print $2}')
        local CURR_MEM=$(systemctl show --user "$SERVICE" --property=MemoryCurrent | awk -F= '{print $2}')
        local CURR_TIME=$(date +%s%N)

        if [[ -z "$CURR_CPU" || -z "$CURR_MEM" ]]; then
            echo "Could not read CPUUsageNSec or MemoryCurrent for $SERVICE. Is the service running?"
            continue
        fi

        local CPU_DELTA=$((CURR_CPU - PREV_CPU))
        local TIME_DELTA=$((CURR_TIME - PREV_TIME))
        local MEM_DELTA=$((CURR_MEM - PREV_MEM))

        # CPU usage percentage calculation
        local CPU_PCT="N/A"
        if [[ $TIME_DELTA -gt 0 && $CPU_DELTA -ge 0 ]]; then
            CPU_PCT=$(awk "BEGIN {printf \"%.2f\", ($CPU_DELTA / $TIME_DELTA) * 100 / $CORES}")
        fi

        # Memory in MB
        local CURR_MEM_MB=$(awk "BEGIN {printf \"%.2f\", $CURR_MEM/1024/1024}")
        local MEM_DELTA_MB=$(awk "BEGIN {printf \"%.2f\", $MEM_DELTA/1024/1024}")

        echo "CPU Usage:    $CPU_PCT %     Memory Usage: $CURR_MEM_MB MB (delta: $MEM_DELTA_MB MB)"
        PREV_CPU=$CURR_CPU
        PREV_MEM=$CURR_MEM
        PREV_TIME=$CURR_TIME
    done
}