ssh: Implement authentication for new ssh server

internal/wisski/ingredient/barrel/ssh/ssh.go

@@ -0,0 +1,32 @@
+package ssh
+
+import (
+	"io"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
+	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/barrel"
+	"github.com/FAU-CDI/wisski-distillery/pkg/environment"
+	"github.com/FAU-CDI/wisski-distillery/pkg/sshx"
+	"github.com/gliderlabs/ssh"
+)
+
+type SSH struct {
+	ingredient.Base
+	Barrel *barrel.Barrel
+}
+
+func (ssh *SSH) Keys() ([]ssh.PublicKey, error) {
+	file, err := ssh.Environment.Open(ssh.Barrel.AuthorizedKeysPath())
+	if environment.IsNotExist(err) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	bytes, err := io.ReadAll(file)
+	if err != nil {
+		return nil, err
+	}
+	return sshx.ParseAllKeys(bytes), nil
+}