#!/usr/bin/env python
#
# Copyright (C) 2016 Rolf Neugebauer <rolf.neugebauer@docker.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#

"""Concurrent and random execution of commands

This utility starts 'n' threads which randomly execute commands from a
file. The file contains a line per command.
"""

import argparse
import random
import threading
import subprocess
import sys
import time

commands = []
status = 0


class thread(threading.Thread):
    def __init__(self, tid, iterations):
        threading.Thread.__init__(self)
        self.tid = tid
        self.iters = iterations

    def run(self):
        for i in range(self.iters):
            if len(commands) > 1:
                idx = random.randrange(0, len(commands))
                cmd = commands[idx]
            else:
                cmd = commands[0]

            print("[THREAD-%03d] %03d: %s\n" % (self.tid, i, cmd))

            ret = subprocess.call(cmd, shell=True)
            if not ret == 0:
                print("[THREAD-%03d] %03d: FAILED with %d\n" % (self.tid, i, ret))
                global status
                status = 1
                return
            print("[THREAD-%03d] %03d: DONE\n" % (self.tid, i))
            # yield
            time.sleep(0)


p = argparse.ArgumentParser()
p.description = "Concurrent and random execution of commands"

p.add_argument("-c", "--concurrent", default=10, type=int,
               help="How many current threads to execute")

p.add_argument("-i", "--iterations", default=10, type=int,
               help="How iterations per thread to execute")

p.add_argument('cmdfile', nargs=1,
               help="File to execute commands from.")


args = p.parse_args()

# read in the commands
with open(args.cmdfile[0], 'r') as f:
    commands = f.readlines()

# create threads
threads = []
for i in range(args.concurrent):
    threads.append(thread(i, args.iterations))

# run threads
for t in threads:
    t.start()

# wait for them to finish
for t in threads:
    t.join()

sys.exit(status)