1. <?php
  3. /**
  4. * Aggregates values from log files with limited memory usage.
  5. *
  6. * @param array $logFiles An array of log file paths.
  7. * @param string $aggregationKey The key to aggregate values by.
  8. * @param callable $aggregationFunction A function to apply for aggregation (e.g., array_sum, array_count_values).
  9. * @return array An associative array containing the aggregated values.
  10. */
  11. function aggregateLogFiles(array $logFiles, string $aggregationKey, callable $aggregationFunction): array
  12. {
  13. $aggregatedData = [];
  15. foreach ($logFiles as $logFile) {
  16. if (file_exists($logFile)) {
  17. $logData = file($logFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES); // Read log file
  18. if ($logData) {
  19. foreach ($logData as $line) {
  20. if (strpos($line, $aggregationKey) !== false) {
  21. // Extract the value based on the aggregation key
  22. preg_match('/' . preg_quote($aggregationKey, '/') . '=\s*([^\s]+)/', $line, $matches);
  23. if (isset($matches[1])) {
  24. $value = trim($matches[1]);
  26. if (isset($aggregatedData[$value])) {
  27. $aggregatedData[$value][] = $value; // Add to existing array
  28. } else {
  29. $aggregatedData[$value] = [$value]; // Create new array
  30. }
  31. }
  32. }
  33. }
  34. }
  35. } else {
  36. error_log("Log file not found: " . $logFile);
  37. }
  38. }
  40. // Apply the aggregation function to the aggregated data
  41. foreach ($aggregatedData as $key => $values) {
  42. $aggregatedData[$key] = $aggregationFunction($values);
  43. }
  45. return $aggregatedData;
  46. }
  48. // Example Usage:
  49. /*
  50. $logFiles = ['log1.txt', 'log2.txt'];
  51. $aggregationKey = 'user_id';
  52. $aggregationFunction = function (array $values) {
  53. return array_count_values($values); // Count occurrences of each user_id
  54. };
  56. $aggregatedResults = aggregateLogFiles($logFiles, $aggregationKey, $aggregationFunction);
  58. print_r($aggregatedResults);
  59. */
  61. ?>

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