Basic System Monitoring

package main

import (
    "fmt"
    "time"

    "github.com/shirou/gopsutil/v4/cpu"
    "github.com/shirou/gopsutil/v4/disk"
    "github.com/shirou/gopsutil/v4/host"
    "github.com/shirou/gopsutil/v4/mem"
)

func displayCPUInfo() error {
    // Get CPU usage percentage
    percentages, err := cpu.Percent(time.Second, false)
    if err != nil {
        return fmt.Errorf("error getting CPU percent: %w", err)
    }

    // Get number of CPU cores
    cores, err := cpu.Counts(true)
    if err != nil {
        return fmt.Errorf("error getting CPU counts: %w", err)
    }

    fmt.Println("\n=== CPU Information ===")
    fmt.Printf("CPU Usage: %.2f%%\n", percentages[0])
    fmt.Printf("CPU Cores: %d\n", cores)

    return nil
}

func displayMemoryInfo() error {
    // Get virtual memory statistics
    vmStat, err := mem.VirtualMemory()
    if err != nil {
        return fmt.Errorf("error getting memory info: %w", err)
    }

    // Get swap memory statistics
    swapStat, err := mem.SwapMemory()
    if err != nil {
        return fmt.Errorf("error getting swap info: %w", err)
    }

    fmt.Println("\n=== Memory Information ===")
    fmt.Printf("Total: %v MB\n", vmStat.Total/1024/1024)
    fmt.Printf("Used: %v MB (%.2f%%)\n", 
        vmStat.Used/1024/1024, vmStat.UsedPercent)
    fmt.Printf("Available: %v MB\n", vmStat.Available/1024/1024)
    fmt.Printf("\nSwap Total: %v MB\n", swapStat.Total/1024/1024)
    fmt.Printf("Swap Used: %v MB (%.2f%%)\n", 
        swapStat.Used/1024/1024, swapStat.UsedPercent)

    return nil
}

func displayDiskInfo() error {
    // Get all partitions
    partitions, err := disk.Partitions(false)
    if err != nil {
        return fmt.Errorf("error getting partitions: %w", err)
    }

    fmt.Println("\n=== Disk Information ===")
    for _, partition := range partitions {
        // Get usage statistics for each partition
        usageStat, err := disk.Usage(partition.Mountpoint)
        if err != nil {
            continue // Skip partitions we can't access
        }

        fmt.Printf("\nDevice: %s\n", partition.Device)
        fmt.Printf("Mountpoint: %s\n", partition.Mountpoint)
        fmt.Printf("Filesystem: %s\n", partition.Fstype)
        fmt.Printf("Total: %v GB\n", usageStat.Total/1024/1024/1024)
        fmt.Printf("Used: %v GB (%.2f%%)\n", 
            usageStat.Used/1024/1024/1024, usageStat.UsedPercent)
        fmt.Printf("Free: %v GB\n", usageStat.Free/1024/1024/1024)
    }

    return nil
}

func displayHostInfo() error {
    // Get host information
    hostInfo, err := host.Info()
    if err != nil {
        return fmt.Errorf("error getting host info: %w", err)
    }

    // Get uptime
    uptime, err := host.Uptime()
    if err != nil {
        return fmt.Errorf("error getting uptime: %w", err)
    }

    fmt.Println("\n=== Host Information ===")
    fmt.Printf("Hostname: %s\n", hostInfo.Hostname)
    fmt.Printf("OS: %s\n", hostInfo.OS)
    fmt.Printf("Platform: %s\n", hostInfo.Platform)
    fmt.Printf("Platform Version: %s\n", hostInfo.PlatformVersion)
    fmt.Printf("Kernel Version: %s\n", hostInfo.KernelVersion)
    fmt.Printf("Uptime: %v hours\n", uptime/3600)

    return nil
}

func main() {
    fmt.Println("System Monitor")
    fmt.Println("==============")

    // Display all system information
    if err := displayHostInfo(); err != nil {
        fmt.Printf("Error: %v\n", err)
    }

    if err := displayCPUInfo(); err != nil {
        fmt.Printf("Error: %v\n", err)
    }

    if err := displayMemoryInfo(); err != nil {
        fmt.Printf("Error: %v\n", err)
    }

    if err := displayDiskInfo(); err != nil {
        fmt.Printf("Error: %v\n", err)
    }
}