Add local and NetBox server notes and improve reliability

internal/notes/notes.go

@@ -0,0 +1,71 @@
+// Package notes stores private server notes independently of the host cache.
+package notes
+
+import (
+	"context"
+	"crypto/sha256"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/netbox"
+	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/storage"
+)
+
+type Note struct {
+	Text, ETag string
+	Host       netbox.HostEntry
+}
+type Service struct {
+	Dir, Namespace string
+	Client         *netbox.Client
+}
+
+func New(namespace string, client *netbox.Client) *Service {
+	dir, err := os.UserConfigDir()
+	if err != nil {
+		dir = filepath.Join(os.Getenv("HOME"), ".config")
+	}
+	return &Service{Dir: filepath.Join(dir, "netssh", "notes"), Namespace: strings.TrimRight(namespace, "/"), Client: client}
+}
+
+func (s *Service) path(host netbox.HostEntry) string {
+	key := fmt.Sprintf("%s\x00%s\x00%s", s.Namespace, host.Kind, strings.ToLower(host.Name))
+	return filepath.Join(s.Dir, fmt.Sprintf("%x.txt", sha256.Sum256([]byte(key))))
+}
+
+func (s *Service) Read(ctx context.Context, host netbox.HostEntry, remote bool) (Note, error) {
+	note := Note{Host: host}
+	if remote {
+		if s.Client == nil {
+			return note, fmt.Errorf("NetBox is not configured")
+		}
+		if host.ID == 0 {
+			resolved, err := s.Client.FindHost(ctx, host.Name, host.Kind)
+			if err != nil {
+				return note, err
+			}
+			note.Host = resolved
+		}
+		var err error
+		note.Text, note.ETag, err = s.Client.GetComments(ctx, note.Host)
+		return note, err
+	}
+	data, err := os.ReadFile(s.path(host))
+	if os.IsNotExist(err) {
+		return note, nil
+	}
+	note.Text = string(data)
+	return note, err
+}
+
+func (s *Service) Write(ctx context.Context, note Note, remote bool) error {
+	if remote {
+		if s.Client == nil {
+			return fmt.Errorf("NetBox is not configured")
+		}
+		return s.Client.SetComments(ctx, note.Host, note.Text, note.ETag)
+	}
+	return storage.WriteFile(s.path(note.Host), []byte(note.Text), 0o600)
+}