A interruptible list

Build a list from a iterable, interruptible by KeyboardInterrupt (SIGINT), and monitorable by SIGUSR1 and SIGUSR2.

The function interruptible_list act as list() constructor, and build a list from an iterable, except:

• When a SIGINT (CTRL-C, KeyboardInterrupt) is received, the construction is stopped, and the current list is returned.
• When a SIGUSR1 is received, the last item is pickled in a file or a callback is called on the last item, and the construction of the list continues.
• When a SIGUSR2 is received, the whole current list is pickled in an file or a callback is called on the whole current list, and the construction of the list continues.

Examples

All examples are illustrated with a slow version of range(60).

import time

def mygen():
    for i in range(60):
        time.sleep(1)
        yield i

• Basic interruptible list:

  from interruptible_list import interruptible_list
  
  L = interruptible_list(mygen())
  

• With callback on SIGUSR1 to display the last item on stderr

  import sys
  from interruptible_list import interruptible_list
  
  def mycallback(x):
      print(x, file=sys.stderr)
  
  L = interruptible_list(mygen(), callback_last=mycallback)
  

• With callback on SIGUSR2 to display the mean on the current list on stderr:

  import sys
  from interruptible_list import interruptible_list
  
  def mycallback_mean(thelist):
      mean = sum(thelist)/len(thelist)
      print(mean, file=sys.stderr)
  
  L = interruptible_list(mygen(), callback_whole=mycallback_mean)
  

• With save on SIGUSR1 and SIGUSR2. Last item (USR1) or the whole current list (USR2) is pickled when the signal is received.

  from interruptible_list import interruptible_list
  
  L = interruptible_list(mygen(), save_last=True, save_whole=True)