chore: publish pxmon v0.2.0

internal/cluster/change_history.go

@@ -0,0 +1,89 @@
+package cluster
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+type ChangeRecord struct {
+	At      time.Time `json:"at"`
+	Action  string    `json:"action"`
+	Target  string    `json:"target"`
+	Details string    `json:"details,omitempty"`
+}
+
+func (s *Service) changeHistoryPath() string {
+	return filepath.Join(s.DataDir(), "history", "changes.log")
+}
+
+func (s *Service) AppendChange(action, target, details string) error {
+	if s == nil {
+		return nil
+	}
+	rec := ChangeRecord{
+		At:      s.now().UTC(),
+		Action:  strings.TrimSpace(action),
+		Target:  strings.TrimSpace(target),
+		Details: strings.TrimSpace(details),
+	}
+	if rec.Action == "" {
+		return nil
+	}
+	path := s.changeHistoryPath()
+	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
+		return err
+	}
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o600)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	b, err := json.Marshal(rec)
+	if err != nil {
+		return err
+	}
+	_, err = f.Write(append(b, '\n'))
+	return err
+}
+
+func (s *Service) ListChanges(limit int) ([]ChangeRecord, error) {
+	path := s.changeHistoryPath()
+	f, err := os.Open(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	defer f.Close()
+	capHint := 32
+	if limit > capHint {
+		capHint = limit
+	}
+	items := make([]ChangeRecord, 0, capHint)
+	sc := bufio.NewScanner(f)
+	sc.Buffer(make([]byte, 0, 64*1024), 2*1024*1024)
+	for sc.Scan() {
+		line := strings.TrimSpace(sc.Text())
+		if line == "" {
+			continue
+		}
+		var rec ChangeRecord
+		if err := json.Unmarshal([]byte(line), &rec); err != nil {
+			continue
+		}
+		items = append(items, rec)
+	}
+	if err := sc.Err(); err != nil {
+		return nil, fmt.Errorf("scan change history: %w", err)
+	}
+	if limit > 0 && len(items) > limit {
+		items = items[len(items)-limit:]
+	}
+	return items, nil
+}