use go's internal flag library to reduce binary size

cmd/root.go

@@ -2,141 +2,115 @@ package cmd
 
 import (
 	"encoding/json"
+	"flag"
 	"fmt"
-	"log/slog"
+	"log"
 	"os"
-	"slices"
 	"strings"
 
-	"github.com/numtide/nixos-facter/pkg/hwinfo"
-
 	"github.com/numtide/nixos-facter/pkg/facter"
-
-	"github.com/spf13/cobra"
+	"github.com/numtide/nixos-facter/pkg/hwinfo"
 )
 
 var (
-	cfgFile          string
 	outputPath       string
 	logLevel         string
 	hardwareFeatures []string
 
 	scanner = facter.Scanner{}
 )
 
-// rootCmd represents the base command when called without any subcommands
-var rootCmd = &cobra.Command{
-	Use:   "nixos-facter",
-	Short: "Hardware report generator",
-	// todo Long description
-	// todo add Long description
-	RunE: func(cmd *cobra.Command, args []string) error {
-		// check the effective user id is 0 e.g. root
-		if os.Geteuid() != 0 {
-			cmd.SilenceUsage = true
-			return fmt.Errorf("you must run this program as root")
-		}
+const usage = `nixos-facter [flags]
+Hardware report generator
 
-		// convert the hardware features into probe features
-		for _, str := range hardwareFeatures {
-			probe, err := hwinfo.ProbeFeatureString(str)
-			if err != nil {
-				return fmt.Errorf("invalid hardware feature: %w", err)
-			}
-			scanner.Features = append(scanner.Features, probe)
-		}
+Usage:
+  nixos-facter [flags]
 
-		// set the log level
-		if logLevel != "" {
-			if logLevel == "debug" {
-				slog.SetLogLoggerLevel(slog.LevelDebug)
-			} else if logLevel == "info" {
-				slog.SetLogLoggerLevel(slog.LevelInfo)
-			} else if logLevel == "warn" {
-				slog.SetLogLoggerLevel(slog.LevelWarn)
-			} else if logLevel == "error" {
-				slog.SetLogLoggerLevel(slog.LevelError)
-			} else {
-				return fmt.Errorf("invalid log level: %s", logLevel)
-			}
-		}
+Flags:
+  -e, --ephemeral          capture all ephemeral properties e.g. swap, filesystems and so on
+  -f, --hardware strings   Hardware items to probe. Possible values are memory,pci,isapnp,net,floppy,misc,misc_serial,misc_par,misc_floppy,serial,cpu,bios,monitor,mouse,scsi,usb,usb_mods,adb,modem,modem_usb,parallel,parallel_lp,parallel_zip,isa,isa_isdn,isdn,kbd,prom,sbus,braille,braille_alva,braille_fhp,braille_ht,ignx11,sys,bios_vbe,isapnp_old,isapnp_new,isapnp_mod,braille_baum,manual,fb,veth,pppoe,scan,pcmcia,fork,parallel_imm,s390,cpuemu,sysfs,s390disks,udev,block,block_cdrom,block_part,edd,edd_mod,bios_ddc,bios_fb,bios_mode,input,block_mods,bios_vesa,cpuemu_debug,scsi_noserial,wlan,bios_crc,hal,bios_vram,bios_acpi,bios_ddc_ports,modules_pata,net_eeprom,x86emu,max,lxrc,all,, (default [memory,pci,net,serial,cpu,bios,monitor,scsi,usb,prom,sbus,sys,sysfs,udev,block,wlan])
+  -h, --help               help for nixos-facter
+  -o, --output string      path to write the report
+  -s, --swap               capture swap entries
 
-		report, err := scanner.Scan()
-		if err != nil {
-			return err
-		}
+`
 
-		bytes, err := json.MarshalIndent(report, "", "  ")
-		if err != nil {
-			return fmt.Errorf("failed to marshal report to json: %w", err)
-		}
+func init() {
+	// Define flags
+	flag.StringVar(&outputPath, "output", "", "path to write the report")
+	flag.BoolVar(&scanner.Swap, "swap", false, "capture swap entries")
+	flag.BoolVar(&scanner.Ephemeral, "ephemeral", false, "capture all ephemeral properties e.g. swap, filesystems and so on")
+	flag.StringVar(&logLevel, "log-level", "info", "log level")
+
+	defaultFeatures := []string{
+		"memory", "pci", "net", "serial", "cpu", "bios", "monitor", "scsi", "usb", "prom", "sbus", "sys", "sysfs",
+		"udev", "block", "wlan",
+	}
 
-		// if a file path is provided write the report to it, otherwise output the report on stdout
-		if outputPath == "" {
-			if _, err = os.Stdout.Write(bytes); err != nil {
-				return fmt.Errorf("failed to write report to stdout: %w", err)
-			}
-			fmt.Println()
-		} else if err = os.WriteFile(outputPath, bytes, 0o644); err != nil {
-			return fmt.Errorf("failed to write report to output path: %w", err)
+	probeFeatures := hwinfo.ProbeFeatureStrings()
+	filteredFeatures := []string{}
+	for _, feature := range probeFeatures {
+		if feature != "default" && feature != "int" {
+			filteredFeatures = append(filteredFeatures, feature)
 		}
+	}
 
+	hardwareFeatures = defaultFeatures
+	flag.Func("hardware", fmt.Sprintf("Hardware items to probe. Possible values are %s", strings.Join(filteredFeatures, ",")), func(flagValue string) error {
+		hardwareFeatures = strings.Split(flagValue, ",")
 		return nil
-	},
+	})
+
+	// Custom usage function
+	flag.Usage = func() { fmt.Fprintf(os.Stderr, "%s\n", usage) }
 }
 
-// Execute adds all child commands to the root command and sets flags appropriately.
-// This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() {
-	err := rootCmd.Execute()
-	if err != nil {
-		os.Exit(1)
-	}
-}
+	flag.Parse()
 
-func init() {
-	// Here you will define your flags and configuration settings.
-	// Cobra supports persistent flags, which, if defined here,
-	// will be global for your application.s
-	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.nixos-facter.yaml)")
+	// Check if the effective user id is 0 e.g. root
+	if os.Geteuid() != 0 {
+		log.Fatalf("you must run this program as root")
+	}
 
-	// Cobra also supports local flags, which will only run when this action is called directly.
-	f := rootCmd.Flags()
-	f.StringVarP(&outputPath, "output", "o", "", "path to write the report")
+	// Convert the hardware features into probe features
+	for _, str := range hardwareFeatures {
+		probe, err := hwinfo.ProbeFeatureString(str)
+		if err != nil {
+			log.Fatalf("invalid hardware feature: %v", err)
+		}
+		scanner.Features = append(scanner.Features, probe)
+	}
 
-	// Options for optional ephemeral system properties.
-	f.BoolVarP(&scanner.Swap, "swap", "s", false, "capture swap entries")
-	f.BoolVarP(&scanner.Ephemeral, "ephemeral", "e", false, "capture all ephemeral properties e.g. swap, filesystems and so on")
-	f.StringVarP(&logLevel, "log-level", "l", "info", "log level")
+	// Set the log level
+	switch logLevel {
+	case "debug":
+		log.SetFlags(log.LstdFlags | log.Lshortfile)
+	case "info":
+		log.SetFlags(log.LstdFlags)
+	case "warn", "error":
+		log.SetFlags(0)
+	default:
+		log.Fatalf("invalid log level: %s", logLevel)
+	}
 
-	// We currently support all probe features at a high level as they share some generic information,
-	// but we do not have mappings for all of their detail sections.
-	// These will be added on a priority / need basis.
+	report, err := scanner.Scan()
+	if err != nil {
+		log.Fatalf("failed to scan: %v", err)
+	}
 
-	defaultFeatures := []string{
-		"memory", "pci", "net", "serial", "cpu", "bios", "monitor", "scsi", "usb", "prom", "sbus", "sys", "sysfs",
-		"udev", "block", "wlan",
+	bytes, err := json.MarshalIndent(report, "", "  ")
+	if err != nil {
+		log.Fatalf("failed to marshal report to json: %v", err)
 	}
 
-	// we strip default and int from the feature list
-	probeFeatures := hwinfo.ProbeFeatureStrings()
-	slices.DeleteFunc(probeFeatures, func(str string) bool {
-		switch str {
-		case "default", "int":
-			return true
-		default:
-			return false
+	// If a file path is provided write the report to it, otherwise output the report on stdout
+	if outputPath == "" {
+		if _, err = os.Stdout.Write(bytes); err != nil {
+			log.Fatalf("failed to write report to stdout: %v", err)
 		}
-	})
-
-	f.StringSliceVarP(
-		&hardwareFeatures,
-		"hardware",
-		"f",
-		defaultFeatures,
-		fmt.Sprintf(
-			"Hardware items to probe. Possible values are %s",
-			strings.Join(probeFeatures, ","),
-		),
-	)
+		fmt.Println()
+	} else if err = os.WriteFile(outputPath, bytes, 0o644); err != nil {
+		log.Fatalf("failed to write report to output path: %v", err)
+	}
 }

go.mod

@@ -4,16 +4,13 @@ go 1.22.3
 
 require (
 	github.com/klauspost/cpuid/v2 v2.2.9-0.20240805145549-92d5326f011e
-	github.com/spf13/cobra v1.8.1
 	github.com/stretchr/testify v1.9.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
-	github.com/spf13/pflag v1.0.5 // indirect
 	golang.org/x/sys v0.22.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -1,9 +1,6 @@
-github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
-github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/klauspost/cpuid/v2 v2.2.9-0.20240805145549-92d5326f011e h1:XLeT7xVis8xyC0F4CqQ2fAcuBar61PMI7GhrUEBBKas=
 github.com/klauspost/cpuid/v2 v2.2.9-0.20240805145549-92d5326f011e/go.mod h1:rqkxqrZ1EhYM9G+hXH7YdowN5R5RGN6NK4QwQ3WMXF8=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
@@ -15,11 +12,6 @@ github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRI
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
-github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
-github.com/spf13/cobra v1.8.1 h1:e5/vxKd/rZsfSJMUX1agtjeTDf+qv1/JdBF8gg5k9ZM=
-github.com/spf13/cobra v1.8.1/go.mod h1:wHxEcudfqmLYa8iTfL+OuZPbBZkmvliBWKIezN3kD9Y=
-github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
-github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=

nix/packages/nixos-facter/gomod2nix.toml

@@ -4,9 +4,6 @@ schema = 3
   [mod."github.com/davecgh/go-spew"]
     version = "v1.1.2-0.20180830191138-d8f796af33cc"
     hash = "sha256-fV9oI51xjHdOmEx6+dlq7Ku2Ag+m/bmbzPo6A4Y74qc="
-  [mod."github.com/inconshreveable/mousetrap"]
-    version = "v1.1.0"
-    hash = "sha256-XWlYH0c8IcxAwQTnIi6WYqq44nOKUylSWxWO/vi+8pE="
   [mod."github.com/klauspost/cpuid/v2"]
     version = "v2.2.9-0.20240805145549-92d5326f011e"
     hash = "sha256-yCZS40L97G7WZHhy/A6I8ArEkyHi86DGAW43SziYPek="
@@ -16,12 +13,6 @@ schema = 3
   [mod."github.com/pmezard/go-difflib"]
     version = "v1.0.1-0.20181226105442-5d4384ee4fb2"
     hash = "sha256-XA4Oj1gdmdV/F/+8kMI+DBxKPthZ768hbKsO3d9Gx90="
-  [mod."github.com/spf13/cobra"]
-    version = "v1.8.1"
-    hash = "sha256-yDF6yAHycV1IZOrt3/hofR+QINe+B2yqkcIaVov3Ky8="
-  [mod."github.com/spf13/pflag"]
-    version = "v1.0.5"
-    hash = "sha256-w9LLYzxxP74WHT4ouBspH/iQZXjuAh2WQCHsuvyEjAw="
   [mod."github.com/stretchr/testify"]
     version = "v1.9.0"
     hash = "sha256-uUp/On+1nK+lARkTVtb5RxlW15zxtw2kaAFuIASA+J0="