code: def discord_sender(webhook_url: str):
      """
      Discord sender wrapper: execute func, send a Discord message with the end status
      (sucessfully finished or crashed) at the end. Also send a Discord message before
      executing func.
  
      `webhook_url`: str
          The Discord webhook URL for posting messages.
          Visit https://support.discordapp.com/hc/en-us/articles/228383668-Intro-to-Webhooks to
          set up your webhook and get your URL.
      """
  
      def decorator_sender(func):
          def send_message(text: str):
              headers = {"Content-Type": "application/json"}
              payload = json.dumps({"content": text})
              r = requests.post(
                  url=webhook_url, data=payload, headers=headers
              )
  
          @functools.wraps(func)
          def wrapper_sender(*args, **kwargs):
              start_time = datetime.datetime.now()
              host_name = socket.gethostname()
              func_name = func.__name__
  
              # Handling distributed training edge case.
              # In PyTorch, the launch of `torch.distributed.launch` sets up a RANK environment variable for each process.
              # This can be used to detect the master process.
              # See https://github.com/pytorch/pytorch/blob/master/torch/distributed/launch.py#L211
              # Except for errors, only the master process will send notifications.
              if "RANK" in os.environ:
                  master_process = int(os.environ["RANK"]) == 0
                  host_name += " - RANK: %s" % os.environ["RANK"]
              else:
                  master_process = True
  
              if master_process:
                  contents = [
                      "Your training has started 🎬",
                      "Machine name: %s" % host_name,
                      "Main call: %s" % func_name,
                      "Starting date: %s"
                      % start_time.strftime(DATE_FORMAT),
                  ]
                  text = "\n".join(contents)
                  send_message(text=text)
  
              try:
                  value = func(*args, **kwargs)
  
                  if master_process:
                      end_time = datetime.datetime.now()
                      elapsed_time = end_time - start_time
                      contents = [
                          "Your training is complete 🎉",
                          "Machine name: %s" % host_name,
                          "Main call: %s" % func_name,
                          "Starting date: %s"
                          % start_time.strftime(DATE_FORMAT),
                          "End date: %s"
                          % end_time.strftime(DATE_FORMAT),
                          "Training duration: %s" % str(elapsed_time),
                      ]
  
                      try:
                          str_value = str(value)
                          contents.append(
                              "Main call returned value: %s" % str_value
                          )
                      except:
                          contents.append(
                              "Main call returned value: %s"
                              % "ERROR - Couldn't str the returned value."
                          )
  
                      text = "\n".join(contents)
                      send_message(text=text)
  
                  return value
  
              except Exception as ex:
                  end_time = datetime.datetime.now()
                  elapsed_time = end_time - start_time
                  contents = [
                      "Your training has crashed ☠️",
                      "Machine name: %s" % host_name,
                      "Main call: %s" % func_name,
                      "Starting date: %s"
                      % start_time.strftime(DATE_FORMAT),
                      "Crash date: %s" % end_time.strftime(DATE_FORMAT),
                      "Crashed training duration: %s\n\n"
                      % str(elapsed_time),
                      "Here's the error:",
                      "%s\n\n" % ex,
                      "Traceback:",
                      "%s" % traceback.format_exc(),
                  ]
                  text = "\n".join(contents)
                  send_message(text=text)
                  raise ex
  
          return wrapper_sender
  
      return decorator_sender
  
file_path: knockknock/knockknock/discord_sender.py
imports: import datetime
  import functools
  import json
  import os
  import requests
  import socket
  import traceback
label_desc: Use image node_id 1 for calling a global function with example usage: discord_sender(webhook_url) and returns: decorator_sender, wrapper_sender, value