ssh: Update welcome message

internal/dis/component/ssh2/server_handler.go

@@ -2,8 +2,8 @@ package ssh2
 
 import (
 	"bufio"
-	"fmt"
 	"io"
+	"strings"
 
 	"github.com/gliderlabs/ssh"
 )
@@ -12,9 +12,78 @@ func (ssh2 *SSH2) setupHandler(server *ssh.Server) {
 	server.Handle(ssh2.handleConnection)
 }
 
+const welcomeMessage = `
+__        ___         _  _____   ____  _     _   _ _ _
+\ \      / (_)___ ___| |/ /_ _| |  _ \(_)___| |_(_) | | ___ _ __ _   _
+ \ \ /\ / /| / __/ __| ' / | |  | | | | / __| __| | | |/ _ \ '__| | | |
+  \ V  V / | \__ \__ \ . \ | |  | |_| | \__ \ |_| | | |  __/ |  | |_| |
+   \_/\_/  |_|___/___/_|\_\___| |____/|_|___/\__|_|_|_|\___|_|   \__, |
+                                                                 |___/
+
+Welcome to the WissKI SSH Server.
+You've successfully authenticated, but we don't provide shell access to
+the main server. You may use this connection as part of a proxy jump to
+connect to your WissKI Instance.
+
+In the following we will provide instructions on how to connect to your
+distillery instance via this server. We will assume
+
+${SLUG}
+
+is the name of the WissKI you want to you want to connect to.
+
+From a linux (or mac, or windows 11) command line you may use: 
+
+ssh -J ${DOMAIN}:2222 www-data@${HOSTNAME}
+
+You may also place the following into your $HOME/.ssh/config file:
+
+Host *.${DOMAIN}
+  ProxyJump ${DOMAIN}.proxy
+  User www-data
+Host ${DOMAIN}.proxy
+  User www-data
+  Hostname ${DOMAIN}
+  Port 2222
+
+and then connect simply via:
+
+ssh ${HOSTNAME}
+
+On windows you should use the "ssh" executable from the command line if
+available. 
+
+If you must, you can also use Putty. 
+
+THIS IS NOT RECOMMENDED AND NOT OFFICIALLY SUPPORTED
+
+First make sure your SSH Key is configured under Connection > Auth > 
+Credentials. Then configure a proxy under Connection > Proxy. The Proxy 
+Hostname should be
+
+${DOMAIN}
+
+and the port "2222". The proxy type should be "SSH to proxy and use
+port forwarding". Then you may enter the hostname 
+
+www-data@${HOSTNAME}
+
+with port 22. 
+
+Press CTRL-C to close this connection.
+`
+
 func (ssh2 *SSH2) handleConnection(session ssh.Session) {
 	slug, _ := getAnyPermission(session.Context())
-	banner := fmt.Sprintf(welcomeMessage, ssh2.Config.DefaultDomain, slug+"."+ssh2.Config.DefaultDomain)
+
+	banner := welcomeMessage
+	for _, oldnew := range [][2]string{
+		{"${SLUG}", slug},
+		{"${DOMAIN}", ssh2.Config.DefaultDomain},
+		{"${HOSTNAME}", slug + "." + ssh2.Config.DefaultDomain},
+	} {
+		banner = strings.ReplaceAll(banner, oldnew[0], oldnew[1])
+	}
 
 	io.WriteString(session, banner)