code: def test_log_monitor(tmp_path, live_dead_pids):
      log_dir = tmp_path / "logs"
      log_dir.mkdir()
      # Create an old dir.
      (log_dir / "old").mkdir()
      worker_id = (
          "6df6d5dd8ca5215658e4a8f9a569a9d98e27094f9cc35a4ca43d272c"
      )
      job_id = "01000000"
      alive_pid, dead_pid = live_dead_pids
  
      mock_publisher = MagicMock()
      log_monitor = LogMonitor(
          "127.0.0.1",
          str(log_dir),
          mock_publisher,
          is_proc_alive,
          max_files_open=5,
      )
  
      # files
      worker_out_log_file = (
          f"worker-{worker_id}-{job_id}-{dead_pid}.out"
      )
      worker_err_log_file = (
          f"worker-{worker_id}-{job_id}-{dead_pid}.err"
      )
      monitor = "monitor.log"
      raylet_out = "raylet.out"
      raylet_err = "raylet.err"
      gcs_server_err = "gcs_server.1.err"
  
      contents = "123"
  
      create_file(log_dir, raylet_err, contents)
      create_file(log_dir, raylet_out, contents)
      create_file(log_dir, gcs_server_err, contents)
      create_file(log_dir, monitor, contents)
      create_file(log_dir, worker_out_log_file, contents)
      create_file(log_dir, worker_err_log_file, contents)
  
      """
      Test files are updated.
      """
      log_monitor.update_log_filenames()
  
      assert len(log_monitor.open_file_infos) == 0
      assert len(log_monitor.closed_file_infos) == 5
      assert log_monitor.can_open_more_files is True
      assert len(log_monitor.log_filenames) == 5
  
      def file_exists(log_filenames, filename):
          for f in log_filenames:
              if filename in f:
                  return True
          return False
  
      assert file_exists(log_monitor.log_filenames, raylet_err)
      assert not file_exists(log_monitor.log_filenames, raylet_out)
      assert file_exists(log_monitor.log_filenames, gcs_server_err)
      assert file_exists(log_monitor.log_filenames, monitor)
      assert file_exists(log_monitor.log_filenames, worker_out_log_file)
      assert file_exists(log_monitor.log_filenames, worker_err_log_file)
  
      def get_file_info(file_infos, filename):
          for file_info in file_infos:
              if filename in file_info.filename:
                  return file_info
          assert False, "Shouldn't reach."
  
      raylet_err_info = get_file_info(
          log_monitor.closed_file_infos, raylet_err
      )
      gcs_server_err_info = get_file_info(
          log_monitor.closed_file_infos, gcs_server_err
      )
      monitor_info = get_file_info(
          log_monitor.closed_file_infos, monitor
      )
      worker_out_log_file_info = get_file_info(
          log_monitor.closed_file_infos, worker_out_log_file
      )
      worker_err_log_file_info = get_file_info(
          log_monitor.closed_file_infos, worker_err_log_file
      )
  
      assert raylet_err_info.is_err_file
      assert gcs_server_err_info.is_err_file
      assert not monitor_info.is_err_file
      assert not worker_out_log_file_info.is_err_file
      assert worker_err_log_file_info.is_err_file
  
      assert worker_out_log_file_info.job_id is None
      assert worker_err_log_file_info.job_id is None
      assert worker_out_log_file_info.worker_pid == int(dead_pid)
      assert worker_out_log_file_info.worker_pid == int(dead_pid)
  
      """
      Test files are opened.
      """
      log_monitor.open_closed_files()
      assert len(log_monitor.open_file_infos) == 5
      assert len(log_monitor.closed_file_infos) == 0
      assert not log_monitor.can_open_more_files
  
      """
      Test files are published.
      """
  
      assert log_monitor.check_log_files_and_publish_updates()
      assert raylet_err_info.worker_pid == "raylet"
      assert gcs_server_err_info.worker_pid == "gcs_server"
      assert monitor_info.worker_pid == "autoscaler"
  
      assert mock_publisher.publish_logs.call_count
  
      for file_info in log_monitor.open_file_infos:
          mock_publisher.publish_logs.assert_any_call(
              {
                  "ip": log_monitor.ip,
                  "pid": file_info.worker_pid,
                  "job": file_info.job_id,
                  "is_err": file_info.is_err_file,
                  "lines": [contents],
                  "actor_name": file_info.actor_name,
                  "task_name": file_info.task_name,
              }
          )
      # If there's no new update, it should return False.
      assert not log_monitor.check_log_files_and_publish_updates()
  
      # Test max lines read == 99 is repsected.
      lines = "1\n" * int(
          1.5 * ray_constants.LOG_MONITOR_NUM_LINES_TO_READ
      )
      with open(raylet_err_info.filename, "a") as f:
          # Write 150 more lines.
          f.write(lines)
  
      assert log_monitor.check_log_files_and_publish_updates()
      mock_publisher.publish_logs.assert_any_call(
          {
              "ip": log_monitor.ip,
              "pid": raylet_err_info.worker_pid,
              "job": raylet_err_info.job_id,
              "is_err": raylet_err_info.is_err_file,
              "lines": [
                  "1"
                  for _ in range(
                      ray_constants.LOG_MONITOR_NUM_LINES_TO_READ
                  )
              ],
              "actor_name": file_info.actor_name,
              "task_name": file_info.task_name,
          }
      )
  
      """
      Test files are closed.
      """
      # log_monitor.open_closed_files() should close all files
      # if it cannot open new files.
      new_worker_err_file = (
          f"worker-{worker_id}-{job_id}-{alive_pid}.err"
      )
      create_file(log_dir, new_worker_err_file, contents)
      log_monitor.update_log_filenames()
  
      # System logs are not closed.
      # - raylet, gcs, monitor
      # Dead workers are not tracked anymore. They will be moved to old folder.
      # - dead pid out & err
      # alive worker is going to be newly opened.
      log_monitor.open_closed_files()
      assert len(log_monitor.open_file_infos) == 2
      assert log_monitor.can_open_more_files
      # Two dead workers are not tracked anymore, and they will be in the old folder.
      # monitor.err and gcs_server.1.err have not been updated, so they remain closed.
      assert len(log_monitor.closed_file_infos) == 2
      assert len(list((log_dir / "old").iterdir())) == 2
  
imports: import io
  import os
  import re
  import subprocess
  import sys
  import tempfile
  import time
  import logging
  from collections import Counter, defaultdict
  from contextlib import redirect_stderr, redirect_stdout
  from pathlib import Path
  from unittest.mock import Mock, MagicMock
  import pytest
  import ray
  from ray._private import ray_constants
  from ray._private.log_monitor import LOG_NAME_UPDATE_INTERVAL_S, RAY_LOG_MONITOR_MANY_FILES_THRESHOLD, LogFileInfo, LogMonitor, is_proc_alive
  from ray._private.test_utils import get_log_batch, get_log_message, get_log_data, init_log_pubsub, run_string_as_driver, wait_for_condition
  from ray.cross_language import java_actor_class
  from ray.autoscaler._private.cli_logger import cli_logger
label_desc: Use image node_id 16 for calling a global function with example usage: test_log_monitor(tmp_path, live_dead_pids) and returns: False, True, file_info