init

cmd/client/main.go

@@ -0,0 +1,155 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/wzray/dns/internal/client"
+)
+
+const defaultServer = "http://localhost:8080"
+
+func main() {
+	os.Exit(run(os.Args[1:], os.Stdout, os.Stderr))
+}
+
+func run(args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("dns-cli", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	server := fs.String("server", envOr("DNS_SERVER_URL", defaultServer),
+		"Base URL of the dns-server (env: DNS_SERVER_URL)")
+	fs.Usage = func() { printRootUsage(stderr, fs) }
+
+	if err := fs.Parse(args); err != nil {
+		return 2
+	}
+	rest := fs.Args()
+	if len(rest) == 0 {
+		printRootUsage(stderr, fs)
+		return 2
+	}
+
+	cmd, cmdArgs := rest[0], rest[1:]
+	c := client.New(*server)
+
+	switch cmd {
+	case "help", "-h", "--help":
+		printRootUsage(stdout, fs)
+		return 0
+	case "list", "ls":
+		return runList(c, cmdArgs, stdout, stderr)
+	case "add":
+		return runAdd(c, cmdArgs, stdout, stderr)
+	case "remove", "rm", "delete":
+		return runRemove(c, cmdArgs, stdout, stderr)
+	default:
+		fmt.Fprintf(stderr, "unknown command: %q\n\n", cmd)
+		printRootUsage(stderr, fs)
+		return 2
+	}
+}
+
+func runList(c *client.Client, args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("list", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	fs.Usage = func() {
+		fmt.Fprintln(stderr, "Usage: dns-cli list")
+		fmt.Fprintln(stderr, "\nList configured DNS nameservers.")
+	}
+	if err := fs.Parse(args); err != nil {
+		return 2
+	}
+	if fs.NArg() != 0 {
+		fmt.Fprintln(stderr, "list: unexpected arguments")
+		fs.Usage()
+		return 2
+	}
+	servers, err := c.List()
+	if err != nil {
+		fmt.Fprintf(stderr, "error: %v\n", err)
+		return 1
+	}
+	if len(servers) == 0 {
+		fmt.Fprintln(stdout, "(no nameservers configured)")
+		return 0
+	}
+	for _, s := range servers {
+		fmt.Fprintln(stdout, s)
+	}
+	return 0
+}
+
+func runAdd(c *client.Client, args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("add", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	fs.Usage = func() {
+		fmt.Fprintln(stderr, "Usage: dns-cli add <address>")
+		fmt.Fprintln(stderr, "\nAdd a DNS nameserver (IPv4 or IPv6).")
+	}
+	if err := fs.Parse(args); err != nil {
+		return 2
+	}
+	if fs.NArg() != 1 {
+		fmt.Fprintln(stderr, "add: exactly one <address> argument is required")
+		fs.Usage()
+		return 2
+	}
+	addr := fs.Arg(0)
+	if err := c.Add(addr); err != nil {
+		fmt.Fprintf(stderr, "error: %v\n", err)
+		return 1
+	}
+	fmt.Fprintf(stdout, "added: %s\n", addr)
+	return 0
+}
+
+func runRemove(c *client.Client, args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("remove", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	fs.Usage = func() {
+		fmt.Fprintln(stderr, "Usage: dns-cli remove <address>")
+		fmt.Fprintln(stderr, "\nRemove a DNS nameserver. Aliases: rm, delete.")
+	}
+	if err := fs.Parse(args); err != nil {
+		return 2
+	}
+	if fs.NArg() != 1 {
+		fmt.Fprintln(stderr, "remove: exactly one <address> argument is required")
+		fs.Usage()
+		return 2
+	}
+	addr := fs.Arg(0)
+	if err := c.Remove(addr); err != nil {
+		fmt.Fprintf(stderr, "error: %v\n", err)
+		return 1
+	}
+	fmt.Fprintf(stdout, "removed: %s\n", addr)
+	return 0
+}
+
+func printRootUsage(w io.Writer, fs *flag.FlagSet) {
+	fmt.Fprintln(w, "dns-cli — manage DNS nameservers on a remote host via the dns-server REST API.")
+	fmt.Fprintln(w)
+	fmt.Fprintln(w, "Usage:")
+	fmt.Fprintln(w, "  dns-cli [global flags] <command> [args]")
+	fmt.Fprintln(w)
+	fmt.Fprintln(w, "Commands:")
+	fmt.Fprintln(w, "  list            List configured DNS nameservers")
+	fmt.Fprintln(w, "  add <address>   Add a DNS nameserver")
+	fmt.Fprintln(w, "  remove <addr>   Remove a DNS nameserver (aliases: rm, delete)")
+	fmt.Fprintln(w, "  help            Show this help")
+	fmt.Fprintln(w)
+	fmt.Fprintln(w, "Global flags:")
+	fs.PrintDefaults()
+	fmt.Fprintln(w)
+	fmt.Fprintln(w, "Run 'dns-cli <command> --help' for command-specific help.")
+}
+
+func envOr(key, def string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return def
+}