refactor: domainName as arg and doc strings

See coop-cloud/organising#163.

cli/server/init.go

@@ -2,7 +2,6 @@ package server
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"net"
 	"time"
@@ -20,7 +19,7 @@ var serverInitCommand = &cli.Command{
 	Usage:     "Initialise server for deploying apps",
 	Aliases:   []string{"i"},
 	HideHelp:  true,
-	ArgsUsage: "<server>",
+	ArgsUsage: "<domain>",
 	Description: `
 Initialise swarm mode on the target <server>.
 
@@ -29,12 +28,9 @@ the default IPv4 address as the advertising address. This can be re-configured
 later for more advanced use cases.
 `,
 	Action: func(c *cli.Context) error {
-		server := c.Args().First()
-		if server == "" {
-			internal.ShowSubcommandHelpAndError(c, errors.New("no server provided"))
-		}
+		domainName := internal.ValidateDomain(c)
 
-		cl, err := client.New(server)
+		cl, err := client.New(domainName)
 		if err != nil {
 			return err
 		}
@@ -51,13 +47,13 @@ later for more advanced use cases.
 		}
 
 		ctx := context.Background()
-		ips, err := resolver.LookupIPAddr(ctx, server)
+		ips, err := resolver.LookupIPAddr(ctx, domainName)
 		if err != nil {
 			logrus.Fatal(err)
 		}
 
 		if len(ips) == 0 {
-			return fmt.Errorf("unable to retrieve ipv4 address for %s", server)
+			return fmt.Errorf("unable to retrieve ipv4 address for %s", domainName)
 		}
 		ipv4 := ips[0].IP.To4().String()