A simple Timer.

timer.py

from datetime import datetime
import json

class Timer:
    def __init__(self, outputFile):
        self.fout = open(outputFile, 'w')
        self.cache = []
        self.records = {}
    
    def start(self, event="time"):
        self.records[event] = datetime.now()

    def stop(self, event='time'):
        end = datetime.now()
        start = self.records[event]
        self.cache.append({
            'event': event,
            'start': start.isoformat(),
            'end': end.isoformat(),
            'elapsed': (end - start).total_seconds()
        })
        del self.records[event]

    def flush(self):
        for row in self.cache:
            self.fout.write(json.dumps(row) + "\n")
            self.fout.flush()
        self.cache = []

    def __del__(self):
        self.flush()
        self.fout.close()

timer = Timer("default-timer.json")