ongoing work on new config system

config/server/nexus.conf

-# Port the API listens to (must be > 1024 and < 65535)
-APIDefaultPort = 1077
+[core]
 
-# Define the range of ports used by each VM for their spice server
-VMSpiceMinPort = 1100
-VMSpiceMaxPort = 65535
+# Supported levels: debug, info, warn, error, fatal, panic.
+log_level = info
 
-# Log level
-# Supported levels: panic, fatal, error, warn, info, debug
-LogLevel = info
+# Port the API listens to (must be > 1024 and < 65535).
+api_default_port = 1077
 
-# Absolute path to QEMU system binary
-QemuSystem = /usr/bin/qemu-system-x86_64
+# Define the range of ports reserved for spice.
+# Each running VM will use a port on the server.
+vm_spice_min_port = 1100
+vm_spice_max_port = 65535
 
-# Absolute path to QEMU image binary
-QemuImg = /usr/bin/qemu-img
+# Directory where temporary files are created.
+tmp_dir = /tmp
 
-# Absolute path to guestfish binary
-Guestfish = /usr/bin/guestfish
+[limits]
 
-# Directory where temporary files are created
-TmpDir = /tmp
-
-MaxUploadSize = 30G
+max_upload_size = 30G
 
 # We estimate that KVM allows for this amount of RAM saving in % (due to page sharing across VMs).
 # 30% seems to be a pretty conservative estimate.
-KsmRamSaving = 0.3
+ksm_ram_saving = 0.3
 
 # To prevent RAM saturation, we refuse running new VMs if more than
 # this amount of memory is being used (in %).
-RamUsageLimit = 0.85
+ram_usage_limit = 0.85
+
+[tools]
+
+# Absolute path to QEMU system binary.
+qemu_system = /usr/bin/qemu-system-x86_64
+
+# Absolute path to QEMU image binary.
+qemu_img = /usr/bin/qemu-img
+
+# Absolute path to guestfish binary.
+guestfish = /usr/bin/guestfish

src/server/config/config.go

+package config
+
+import (
+    "os"
+    "strings"
+    "path/filepath"
+    "nexus-server/logger"
+    "gopkg.in/ini.v1"
+    "github.com/sirupsen/logrus"
+)
+
+type Config struct {
+    Core struct {
+        TmpDir string `ini:"tmp_dir"`
+        LogLevel string `ini:"log_level"`
+        APIDefaultPort int `ini:"api_default_port"`
+        VMSpiceMinPort int `ini:"vm_spice_min_port"`
+        VMSpiceMaxPort int `ini:"vm_spice_max_port"`
+    } `ini:"core"`
+
+    Limits struct {
+        MaxUploadSize string `ini:"max_upload_sizeize"`
+        KsmRamSaving float64 `ini:"ksm_ram_saving"`
+        RamUsageLimit float64 `ini:"ram_usage_limit"`
+    } `ini:"limits"`
+
+    Tools struct {
+        QemuSystem string `ini:"qemu_system"`
+        QemuImg string `ini:"qemu_img"`
+        Guestfish string `ini:"guestfish"`
+    } `ini:"tools"`
+
+    // Unix permissions when creating directories: when creating templates and VMs and for tmp directory.
+    MkDirPerm os.FileMode
+
+    VMPwdLength int
+    VMPwdDigitCount int
+    VMPwdSymbolCount int
+    VMPwdRepeatChars bool
+
+    UsersFile string
+    DataDir string
+    VMsDir string
+    TemplatesDir string
+    CertsDir string
+}
+
+var log = logger.GetInstance()
+var config *Config
+
+func GetInstance() *Config {
+    return config
+}
+
+func Init() {
+    certsDir := "../certs"
+    configDir := "../config"
+    dataDir := "../dataDir"
+
+    conf, err := ini.LoadSources(ini.LoadOptions{
+        Loose: false,
+    }, filepath.Join(configDir, "nexus.conf"))
+    if err != nil {
+        log.Fatal("Failed reading config file: "+err.Error())
+    }
+
+    config = &Config {}
+    err = conf.StrictMapTo(config)
+    if err != nil {
+       log.Fatal("Failed parsing config file: "+err.Error())
+    }
+
+    // Limits struct {
+    //     MaxUploadSize string `ini:"max_upload_sizeize"`
+    //     KsmRamSaving float64 `ini:"ksm_ram_saving"`
+    //     RamUsageLimit float64 `ini:"ram_usage_limit"`
+    // } `ini:"limits"`
+
+    // Tools struct {
+    //     QemuSystem string `ini:"qemu_system"`
+    //     QemuImg string `ini:"qemu_img"`
+    //     Guestfish string `ini:"guestfish"`
+    // } `ini:"tools"`
+
+    if config.Core.TmpDir == "" {
+        log.Fatal("Config file error: tmp_dir must be defined")
+    }
+    _, err = os.Stat(config.Core.TmpDir)
+    if err != nil {
+        log.Fatal("Config file error: tmp_dir \""+config.Core.TmpDir+"\": "+err.Error())
+    }
+
+    if config.Core.LogLevel == "" {
+        log.Fatal("Config file error: log_level must be defined")
+    }
+    loglevelStr := strings.ToLower(config.Core.LogLevel)
+    switch loglevelStr {
+        case "debug":
+            log.SetLevel(logrus.DebugLevel)
+        case "info":
+            log.SetLevel(logrus.InfoLevel)
+        case "warn":
+            log.SetLevel(logrus.WarnLevel)
+        case "error":
+            log.SetLevel(logrus.ErrorLevel)
+        case "fatal":
+            log.SetLevel(logrus.FatalLevel)
+        case "panic":
+            log.SetLevel(logrus.PanicLevel)
+        default:
+            log.Fatal("Config file error: invalid log_level")
+    }
+
+    if config.Core.APIDefaultPort < 1025 || config.Core.APIDefaultPort > 65535 {
+        log.Fatal("Config file error: invalid api_default_port value")
+    }
+
+    if config.Core.VMSpiceMinPort < 1025 || config.Core.VMSpiceMinPort > 65535 {
+        log.Fatal("Config file error: invalid vm_spice_min_port value")
+    }
+    if config.Core.VMSpiceMaxPort < 1025 || config.Core.VMSpiceMaxPort > 65535 {
+        log.Fatal("Config file error: invalid vm_spice_max_port value")
+    }
+    if config.Core.VMSpiceMaxPort <= config.Core.VMSpiceMinPort {
+        log.Fatal("Config file error: vm_spice_max_port must be > vm_spice_min_port value")
+    }
+
+
+    config.MkDirPerm = 0750
+    config.VMPwdLength = 8
+    config.VMPwdDigitCount = 4
+    config.VMPwdSymbolCount = 0
+    config.VMPwdRepeatChars = false
+    
+    config.UsersFile = filepath.Join(configDir, "/users.json")
+    config.DataDir = dataDir
+    config.VMsDir = filepath.Join(dataDir, "/vms")
+    config.TemplatesDir = filepath.Join(dataDir, "/templates")
+    config.CertsDir = certsDir
+
+    log.Info("TmpDir: ", config.Core.TmpDir)
+    os.Exit(1)
+
+    // Deletes temp directory and its content.
+    if err := os.RemoveAll(config.Core.TmpDir); err != nil {
+        log.Fatal("Failed deleting tmp directory: "+err.Error())
+    }
+
+    if err := os.Mkdir(config.Core.TmpDir, config.MkDirPerm); err != nil {
+        log.Fatal("Failed creating tmp dir: "+err.Error())
+    }
+}

src/server/config/go.mod

+module nexus-server/config
+
+go 1.18

src/server/consts/consts.go

-package consts
-
-const (
-    DefaultLogLevel = "info"
-
-    APIDefaultPort = 1077
-    
-    VMSpiceMinPort = 1100
-    VMSpiceMaxPort = 65535
-
-    VMPwdLength = 8
-    VMPwdDigitCount = 4
-    VMPwdSymbolCount = 0
-    VMPwdRepeatChars = false
-
-    MaxUploadSize = "30G"
-
-    // We estimate that KVM allows for this amount of RAM saving in % (due to page sharing across VMs).
-    // 30% seems to be a pretty conservative estimate.
-    KsmRamSaving = 0.3
-
-    // To prevent RAM saturation, we refuse running new VMs if more than
-    // this amount of memory is being used (in %).
-    RamUsageLimit = .85
-)

src/server/consts/go.mod

-module nexus-server/consts
-
-go 1.18

src/server/go.mod

@@ -10,8 +10,6 @@ replace nexus-common/params => ../common/params
 
 replace nexus-common/caps => ../common/caps
 
-replace nexus-server/consts => ./consts
-
 replace nexus-server/users => ./users
 
 replace nexus-server/logger => ./logger
@@ -24,6 +22,8 @@ replace nexus-server/utils => ./utils
 
 replace nexus-server/paths => ./paths
 
+replace nexus-server/config => ./config
+
 replace nexus-server/cleaner => ./cleaner
 
 replace nexus-server/exec => ./exec
@@ -35,7 +35,6 @@ replace nexus-server/version => ./version
 require (
 	github.com/sirupsen/logrus v1.9.0
 	nexus-server/cleaner v0.0.0-00010101000000-000000000000
-	nexus-server/consts v0.0.0-00010101000000-000000000000
 	nexus-server/logger v0.0.0-00010101000000-000000000000
 	nexus-server/paths v0.0.0-00010101000000-000000000000
 	nexus-server/router v0.0.0-00010101000000-000000000000
@@ -63,10 +62,12 @@ require (
 	golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect
 	golang.org/x/text v0.3.7 // indirect
 	golang.org/x/time v0.0.0-20201208040808-7e3f01d25324 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
 	nexus-common/caps v0.0.0-00010101000000-000000000000 // indirect
 	nexus-common/params v0.0.0-00010101000000-000000000000 // indirect
 	nexus-common/template v0.0.0-00010101000000-000000000000 // indirect
 	nexus-common/vm v0.0.0-00010101000000-000000000000 // indirect
+	nexus-server/config v0.0.0-00010101000000-000000000000 // indirect
 	nexus-server/exec v0.0.0-00010101000000-000000000000 // indirect
 	nexus-server/qga v0.0.0-00010101000000-000000000000 // indirect
 	nexus-server/version v0.0.0-00010101000000-000000000000 // indirect

src/server/go.sum

@@ -72,6 +72,8 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
+gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
+gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

src/server/nexus-server.go

@@ -2,10 +2,7 @@ package main
 
 import (
     "os"
-    "fmt"
     "path"
-    "flag"
-    "strings"
     "nexus-server/vms"
     "nexus-server/exec"
     "nexus-server/paths"
@@ -13,7 +10,7 @@ import (
     "nexus-server/utils"
     "nexus-server/router"
     "nexus-server/logger"
-    "nexus-server/consts"
+    "nexus-server/config"
     "nexus-server/cleaner"
     "nexus-server/version"
     "github.com/sirupsen/logrus"
@@ -28,6 +25,7 @@ func main() {
     log.Info(appname+" version "+version.Get().String())
 
     // These two lines must be executed very early on (basically, here).
+    config.Init()
     paths.Init()
     utils.RandInit()
 
@@ -41,32 +39,6 @@ func main() {
         log.Fatal(err)
     }
 
-    usage := func() {
-        fmt.Println("Usage of "+appname+":")
-        flag.PrintDefaults()
-        os.Exit(1)
-    }
-
-    loglevelFlag := flag.String("l", consts.DefaultLogLevel, "Log level: debug, info, warn, error, fatal")
-    flag.Parse()
-
-    loglevelStr := strings.ToLower(*loglevelFlag)
-    switch loglevelStr {
-        case "debug":
-            log.SetLevel(logrus.DebugLevel)
-        case "info":
-            log.SetLevel(logrus.InfoLevel)
-        case "warn":
-            log.SetLevel(logrus.WarnLevel)
-        case "error":
-            log.SetLevel(logrus.ErrorLevel)
-        case "fatal":
-            log.SetLevel(logrus.FatalLevel)
-        default:
-            log.Error("Invalid log level!")
-            usage()
-    }
-
     err := users.InitUsers()
     if err != nil {
         log.Fatal(err.Error())
@@ -85,5 +57,5 @@ func main() {
 
     cleaner.Start()
 
-    router.New().Start(consts.APIDefaultPort)
+    router.New().Start(config.GetInstance().Core.APIDefaultPort)
 }

src/server/paths/paths.go

@@ -6,7 +6,6 @@ import (
 )
 
 type Paths struct {
-    ConfigDir string
     UsersFile string
     DataDir string
     VMsDir string
@@ -24,11 +23,10 @@ func GetInstance() *Paths {
 
 func Init() {
     certs := "../certs"
-    config := "../config"
+    conf := "../config"
     data := "../data"
     paths = &Paths {
-        ConfigDir: config,
-        UsersFile: filepath.Join(config, "/users.json"),
+        UsersFile: filepath.Join(conf, "/users.json"),
         DataDir: data,
         VMsDir: filepath.Join(data, "/vms"),
         TemplatesDir: filepath.Join(data, "/templates"),

src/server/router/router.go

@@ -12,7 +12,7 @@ import (
     "nexus-server/paths"
     "nexus-server/users"
     "nexus-server/logger"
-    "nexus-server/consts"
+    "nexus-server/config"
     "github.com/labstack/echo/v4"
     "github.com/labstack/echo/v4/middleware"
 )
@@ -27,6 +27,7 @@ type Router struct {
 }
 
 var log = logger.GetInstance()
+var conf = config.GetInstance()
 
 func New() *Router {
     return &Router{
@@ -45,7 +46,7 @@ func (router *Router)Start(port int) {
     }
 
     router.echo.HideBanner = true
-    router.echo.Use(middleware.BodyLimit(consts.MaxUploadSize))
+    router.echo.Use(middleware.BodyLimit(conf.Limits.MaxUploadSize))
 
     // Login management.
     router.echo.POST("/login", auth.Login)

src/server/vms/template.go

@@ -56,7 +56,7 @@ func NewTemplateFromVM(name, owner, access string, vm *VM) (*Template, error) {
 
     // Creates the template directory.
     templateDir := template.getTemplateDir()
-    if err := os.Mkdir(templateDir, 0750); err != nil {
+    if err := os.Mkdir(templateDir, conf.MkDirPerm); err != nil {
         msg := "Failed creating template dir: " + err.Error()
         log.Error(msg)
         vm.mutex.Unlock()
@@ -109,7 +109,7 @@ func NewTemplateFromQCOW(name, owner, access, qcowFile string) (*Template, error
 
     // Creates the template directory.
     templateDir := template.getTemplateDir()
-    if err := os.Mkdir(templateDir, 0750); err != nil {
+    if err := os.Mkdir(templateDir, conf.MkDirPerm); err != nil {
         msg := "Failed creating template dir: " + err.Error()
         log.Error(msg)
         return nil, errors.New(msg)

src/server/vms/vm.go

@@ -255,7 +255,7 @@ func (vm *VM)writeFiles() error {
     }
 
     // Creates the 3-directory structure.
-    if err = os.MkdirAll(vm.dir, 0750); err != nil {
+    if err = os.MkdirAll(vm.dir, conf.MkDirPerm); err != nil {
         msg := "Failed creating VM dirs: "+err.Error()
         log.Error(msg)
         return errors.New(msg)

src/server/vms/vms.go

@@ -19,7 +19,7 @@ import (
     "nexus-server/utils"
     "nexus-server/users"
     "nexus-server/logger"
-    c "nexus-server/consts"
+    "nexus-server/config"
     "github.com/google/uuid"
 )
 
@@ -36,6 +36,7 @@ type (
 )
 
 var log = logger.GetInstance()
+var conf = config.GetInstance()
 var vms *VMs
 
 // Returns a VMs singleton to access this module's public functions.
@@ -51,7 +52,7 @@ func GetVMsInstance() *VMs {
 func InitVMs() error {
     vmsDir := paths.GetInstance().VMsDir
     vms = &VMs { m: make(map[string]*VM), dir: vmsDir, rwlock: new(sync.RWMutex), usedRAM: 0 }
-    vms.usedPorts[c.APIDefaultPort] = true
+    vms.usedPorts[conf.Core.APIDefaultPort] = true
 
     errMsg := "Failed reading VMs directory: "
     dirs1, err := utils.GetSubDirs(vmsDir)
@@ -229,13 +230,13 @@ func (vms *VMs)StartVMWithCreds(vmID uuid.UUID, port int, checkPort bool, pwd st
     }
 
     // We estimate ~30% of RAM saving thanks to KSM (due to page sharing across VMs).
-    estimatedVmRAM := int(math.Round(float64(vm.v.Ram)*(1.-c.KsmRamSaving)))
+    estimatedVmRAM := int(math.Round(float64(vm.v.Ram)*(1.-conf.Limits.KsmRamSaving)))
 
     vms.usedRAM += estimatedVmRAM
 
     // Checks that enough available RAM would be left after the VM has started,
     // otherwise, refuses to run it in order to avoid RAM saturation.
-    if availRAM - vms.usedRAM <= int(math.Round(float64(totalRAM)*(1.-c.RamUsageLimit))) {
+    if availRAM - vms.usedRAM <= int(math.Round(float64(totalRAM)*(1.-conf.Limits.RamUsageLimit))) {
         vms.usedRAM -= estimatedVmRAM
         return errors.New(prefix+"insufficient free RAM")
     }
@@ -332,7 +333,7 @@ func (vms *VMs)allocateFreeRandomPort() int {
     defer vms.rwlock.Unlock()
 
     for {
-        port := utils.Rand(c.VMSpiceMinPort, c.VMSpiceMaxPort)
+        port := utils.Rand(conf.Core.VMSpiceMinPort, conf.Core.VMSpiceMaxPort)
         if !vms.usedPorts[port] {
             if utils.IsPortAvailable(port) {
                 vms.usedPorts[port] = true
@@ -350,7 +351,7 @@ func (vms *VMs)StartVM(vmID uuid.UUID) (int, string, error) {
 
     // Randomly generates a 8 characters long password with 4 digits, 0 symbols,
     // allowing upper and lower case letters, disallowing repeat characters.
-    pwd, err := passwordGen.Generate(c.VMPwdLength, c.VMPwdDigitCount, c.VMPwdSymbolCount, false, c.VMPwdRepeatChars)
+    pwd, err := passwordGen.Generate(conf.VMPwdLength, conf.VMPwdDigitCount, conf.VMPwdSymbolCount, false, conf.VMPwdRepeatChars)
     if err != nil {
         msg := "Failed starting VM: password generation error: "+err.Error()
         log.Error(msg)