Implemented add and fix with some error handling (no saving yet)

cmd/main.go

@@ -1,9 +1,9 @@
 package main
 
 import (
-	"flag"
 	"fmt"
 	"github.com/cbednarski/hostess"
+	"github.com/codegangsta/cli"
 	"os"
 )
 
@@ -20,6 +20,8 @@ const help = `Hostess: an idempotent tool for managing /etc/hosts
 Commands will exit 0 or 1 in a sensible way so you can use the exit code for
 bash and make scripting. Add -h to any command to learn more about it.
 
+To preview a hostess-managed hostsfile run ` + "`" + `hostess fix -n` + "`" + `
+
 WARNING: This program is BETA and not all commands are implemented.
 
 Commands:
@@ -37,7 +39,7 @@ Commands:
 
 Options:
 
-   -f   Force write to the hostfile even if there are errors or conflicts
+   -f   Force write to the hostsfile even if there are errors or conflicts
    -n   No-op. Show changes but don't write them.
    -q   Supress error messages
    -s   Supress success messages (implies -q)
@@ -50,56 +52,77 @@ Report bugs at https://github.com/cbednarski/hostess
 `
 
 func main() {
-	hostfile := hostess.NewHostfile(hostess.GetHostsPath())
-	hostfile.Load()
-	hostfile.Parse()
-
-	flags := make(map[string]*bool)
+	app := cli.NewApp()
+	app.Name = "hostess"
+	app.Usage = help
+	app.Version = "0.1.0"
 
-	flags["force"] = flag.Bool("f", false, "Forcibly apply changes, even if there are errors or conflicts")
-	flags["noop"] = flag.Bool("n", false, "No-op. Show changes but don't write them.")
-	flags["quiet"] = flag.Bool("q", false, "Suppress error and conflict messages.")
-	flags["silent"] = flag.Bool("s", false, "Suppress all output. Check exit codes for success / failure.")
-	flags["help"] = flag.Bool("h", false, "Help")
-
-	flag.Parse()
+	var err error = nil
 
-	// Guard against zero arguments
-	var args []string
-	if len(flag.Args()) > 0 {
-		args = flag.Args()[1:]
+	app.Flags = []cli.Flag{
+		cli.BoolFlag{
+			Name:  "f",
+			Usage: "Force",
+		},
+		cli.BoolFlag{
+			Name:  "n",
+			Usage: "Noop",
+		},
+		cli.BoolFlag{
+			Name:  "q",
+			Usage: "Quiet",
+		},
+		cli.BoolFlag{
+			Name:  "s",
+			Usage: "Silent",
+		},
 	}
 
-	var err error = nil
-
-	switch flag.Arg(0) {
-	case "add":
-		err = hostess.Add(args, flags)
-	case "del":
-		err = hostess.Del(args, flags)
-	case "has":
-		err = hostess.Has(args, flags)
-	case "off":
-		err = hostess.Fix(args, flags)
-	case "on":
-		err = hostess.Fix(args, flags)
-	case "ls":
-		err = hostess.Fix(args, flags)
-	case "fix":
-		err = hostess.Fix(args, flags)
-	case "dump":
-		err = hostess.Fix(args, flags)
-	case "apply":
-		err = hostess.Fix(args, flags)
-
-	default:
-		fmt.Print(help)
+	app.Commands = []cli.Command{
+		{
+			Name: "add",
+			// Usage: "add a task to the list",
+			Action: hostess.Add,
+			Flags:  app.Flags,
+		},
+		{
+			Name: "fix",
+			// Usage: "add a task to the list",
+			Action: hostess.Fix,
+			Flags:  app.Flags,
+		},
 	}
 
+	// switch flag.Arg(0) {
+	// case "add":
+	// 	err = hostess.Add(args, flags)
+	// case "del":
+	// 	err = hostess.Del(args, flags)
+	// case "has":
+	// 	err = hostess.Has(args, flags)
+	// case "off":
+	// 	err = hostess.Off(args, flags)
+	// case "on":
+	// 	err = hostess.On(args, flags)
+	// case "ls":
+	// 	err = hostess.Ls(args, flags)
+	// case "fix":
+	// 	err = hostess.Fix(args, flags)
+	// case "dump":
+	// 	err = hostess.Dump(args, flags)
+	// case "apply":
+	// 	err = hostess.Apply(args, flags)
+
+	// default:
+	// 	fmt.Print(help)
+	// }
+
 	if err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}
 
+	app.Run(os.Args)
+
 	os.Exit(0)
 }

commands.go

@@ -1,44 +1,112 @@
 package hostess
 
 import (
-	"errors"
+	// "errors"
+	"fmt"
+	"github.com/codegangsta/cli"
+	"os"
 )
 
-func Add(args []string, flags map[string]*bool) error {
-	if len(args) > 2 {
-		return errors.New("Unexpected arguments")
+func MaybeErrorln(c *cli.Context, message string) {
+	if !c.Bool("q") {
+		fmt.Printf("%s: %s\n", c.Command.Name, message)
 	}
-	return nil
 }
 
-func Del(args []string, flags map[string]*bool) error {
-	return nil
+func MaybeError(c *cli.Context, message string) {
+	if !c.Bool("q") {
+		fmt.Printf("%s: %s\n", c.Command.Name, message)
+	}
+	os.Exit(1)
+}
+
+func MaybePrintln(c *cli.Context, message string) {
+	if !c.Bool("s") {
+		fmt.Println(message)
+	}
+}
+
+func MaybeLoadHostFile(c *cli.Context) *Hostfile {
+	hostsfile, errs := LoadHostFile()
+	if len(errs) > 0 && !c.Bool("f") {
+		for _, err := range errs {
+			MaybeErrorln(c, err.Error())
+		}
+		MaybeError(c, "Errors while parsing hostsfile")
+	}
+	return hostsfile
+}
+
+func SprintEnabled(on bool) string {
+	if on {
+		return "(On)"
+	} else {
+		return "(Off)"
+	}
 }
 
-func Has(args []string, flags map[string]*bool) error {
+func Add(c *cli.Context) {
+	if len(c.Args()) != 2 {
+		MaybeError(c, "expected <hostname> <ip>")
+	}
+
+	hostsfile := MaybeLoadHostFile(c)
+	hostname := Hostname{c.Args()[0], c.Args()[1], true}
+	err := hostsfile.Add(hostname)
+	if err == nil {
+		if c.Bool("n") {
+			fmt.Println(hostsfile.Format())
+		} else {
+			MaybePrintln(c, fmt.Sprintf("Added %s -> %s %s", hostname.Domain, hostname.Ip, SprintEnabled(hostname.Enabled)))
+			hostsfile.Save()
+		}
+	} else {
+		MaybeError(c, err.Error())
+	}
+}
+
+func Del(c *cli.Context) error {
 	return nil
 }
 
-func Off(args []string, flags map[string]*bool) error {
+func Has(c *cli.Context) error {
 	return nil
 }
 
-func On(args []string, flags map[string]*bool) error {
+func Off(c *cli.Context) error {
 	return nil
 }
 
-func Ls(args []string, flags map[string]*bool) error {
+func On(c *cli.Context) error {
 	return nil
 }
 
-func Fix(args []string, flags map[string]*bool) error {
+func Ls(c *cli.Context) error {
 	return nil
 }
 
-func Dump(args []string, flags map[string]*bool) error {
+const fix_help = `Programmatically rewrite your hostsfile.
+
+Domains pointing to the same IP will be consolidated, sorted, and extra
+whitespace and comments will be removed.
+
+   hostess fix      Rewrite the hostsfile
+   hostess fix -n   Show the new hostsfile. Don't write it
+`
+
+func Fix(c *cli.Context) {
+	hostfile := MaybeLoadHostFile(c)
+	if c.Bool("n") {
+		fmt.Println(hostfile.Format())
+	} else {
+		hostfile.Save()
+	}
+}
+
+func Dump(c *cli.Context) error {
 	return nil
 }
 
-func Apply(args []string, flags map[string]*bool) error {
+func Apply(c *cli.Context) error {
 	return nil
 }

hostess.go

@@ -150,6 +150,13 @@ func NewHostfile(path string) *Hostfile {
 	return &Hostfile{path, make(map[string]*Hostname), ""}
 }
 
+func LoadHostFile() (*Hostfile, []error) {
+	hostfile := NewHostfile(GetHostsPath())
+	hostfile.Load()
+	errs := hostfile.Parse()
+	return hostfile, errs
+}
+
 func (h *Hostfile) Load() string {
 	data, err := ioutil.ReadFile(h.Path)
 	if err != nil {
@@ -160,12 +167,17 @@ func (h *Hostfile) Load() string {
 	return h.data
 }
 
-func (h *Hostfile) Parse() {
+func (h *Hostfile) Parse() []error {
+	var errs []error
 	for _, v := range strings.Split(h.data, "\n") {
 		for _, hostname := range parseLine(v) {
-			h.Add(hostname)
+			err := h.Add(hostname)
+			if err != nil {
+				errs = append(errs, err)
+			}
 		}
 	}
+	return errs
 }
 
 func getSortedMapKeys(m map[string][]string) []string {