Add log viewer

internal/service/service.go

@@ -1,6 +1,7 @@
 package service
 
 import (
+	"bytes"
 	"context"
 	"crypto/rand"
 	"encoding/hex"
@@ -65,6 +66,51 @@ func (s *Service) RunQueue(ctx context.Context) { s.queue.Run(ctx) }
 func (s *Service) Stop()                        { s.queue.Stop() }
 func (s *Service) Config() model.Config         { s.mu.RLock(); defer s.mu.RUnlock(); return s.config }
 func (s *Service) Runs() []model.Run            { return s.queue.Snapshot() }
+func (s *Service) Logs() map[string]any {
+	return map[string]any{
+		"daemon": tailFile("/var/log/urbm.log", 512*1024, 300),
+		"runs":   runsWithLogs(s.queue.Snapshot(), 25),
+	}
+}
+
+func runsWithLogs(runs []model.Run, limit int) []model.Run {
+	result := make([]model.Run, 0, limit)
+	for index := len(runs) - 1; index >= 0 && len(result) < limit; index-- {
+		if len(runs[index].LiveLog) == 0 {
+			continue
+		}
+		result = append(result, runs[index])
+	}
+	return result
+}
+
+func tailFile(path string, maxBytes int64, maxLines int) map[string]any {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return map[string]any{"path": path, "lines": []string{}, "error": "Logdatei ist noch nicht vorhanden"}
+		}
+		return map[string]any{"path": path, "lines": []string{}, "error": err.Error()}
+	}
+	truncatedBytes := 0
+	if int64(len(data)) > maxBytes {
+		truncatedBytes = len(data) - int(maxBytes)
+		data = data[len(data)-int(maxBytes):]
+		if index := bytes.IndexByte(data, '\n'); index >= 0 && index+1 < len(data) {
+			data = data[index+1:]
+		}
+	}
+	rawLines := strings.Split(strings.TrimRight(string(data), "\n"), "\n")
+	if len(rawLines) == 1 && rawLines[0] == "" {
+		rawLines = []string{}
+	}
+	truncatedLines := 0
+	if len(rawLines) > maxLines {
+		truncatedLines = len(rawLines) - maxLines
+		rawLines = rawLines[len(rawLines)-maxLines:]
+	}
+	return map[string]any{"path": path, "lines": rawLines, "truncatedBytes": truncatedBytes, "truncatedLines": truncatedLines}
+}
 
 func (s *Service) BrowseDirectories(path string) ([]platform.DirectoryEntry, error) {
 	if path == "" || path == "/" {