vms.go

package vms

import (
    "os"
    "sort"
    "sync"
    "math"
    "errors"
    "path/filepath"
    "nexus-server/exec"
    "nexus-server/caps"
    "nexus-server/paths"
    "nexus-server/utils"
    "nexus-server/logger"
    "nexus-server/consts"
    "github.com/google/uuid"
)

type (
    VMKeeperFn func(vm VM) bool

    VMs struct {
        m map[string]VM
        dir string             // Base directory where VMs are stored
        rwlock *sync.RWMutex   // RWlock to ensure the coherency of the map (m) of VMs
        usedPorts [65536]bool  // Indicates which ports are used by the VMs
        usedRAM int            // Used RAM by running VMs (in MB)
    }
)

var log = logger.GetInstance()
var vms *VMs

// Returns a VMs "singleton".
// IMPORTANT: the InitVMs function must have been previously called!
func GetVMsInstance() *VMs {
    return vms
}

// Creates all VMs from their files on disk.
// NOTE: path is the root directory where VMs reside.
func InitVMs() error {
    vmsDir := paths.GetInstance().VMsDir
    vms = &VMs { m: make(map[string]VM), dir: vmsDir, rwlock: new(sync.RWMutex), usedRAM: 0 }

    errMsg := "Failed reading VMs directory: "
    dirs1, err := utils.GetSubDirs(vmsDir)
    if err != nil {
        return errors.New(errMsg+err.Error())
    }

    for d1 := range(dirs1) {
        dirs2, err := utils.GetSubDirs(dirs1[d1])
        if err != nil {
            return errors.New(errMsg+err.Error())
        }

        for d2 := range(dirs2) {
            dirs3, err := utils.GetSubDirs(dirs2[d2])
            if err != nil {
                return errors.New(errMsg+err.Error())
            }

            for i := range(dirs3) {
                vmDir := dirs3[i]
                filename := filepath.Join(vmDir, vmConfFile)
                vm, err := newVMFromFile(filename)
                if err != nil {
                    log.Warn("Skipping VM: failed reading \""+filename+"\" "+err.Error())
                    continue