iPython notebook keyboard interrupt breaks cell when using Halo

[manrajgrover]

Description

Currently, in an iPython notebook, if a user does not handle keyboard interrupt and the spinner is running, a KeyboardInterrupt is thrown but the spinner keeps spinning.

System settings

• Operating System: MacOS
• Terminal in use: iTerm 2
• Python version: 2.7.10
• Halo version: 0.0.8

Error

Expected behaviour

In [5]: import time
   ...: import random
   ...:
   ...: spinner.start()
   ...: for i in range(100):
   ...:     spinner.text = '{0}% Downloaded dataset.zip'.format(i)
   ...:     time.sleep(random.random())
   ...: spinner.succeed('Downloaded dataset.zip')
   ...:
⠹ 4% Downloaded dataset.zip^C---------------------------------------------------------------------------
KeyboardInterrupt                         Traceback (most recent call last)
<ipython-input-5-81a625f23371> in <module>()
      5 for i in range(100):
      6     spinner.text = '{0}% Downloaded dataset.zip'.format(i)
----> 7     time.sleep(random.random())
      8 spinner.succeed('Downloaded dataset.zip')
      9

KeyboardInterrupt:

⠼ 4% Downloaded

Steps to recreate

Following snippet should recreate the error.

In [1]: from halo import Halo

In [2]: spinner = Halo(text='Downloading dataset.zip', spinner='dots')

In [3]: import time
   ...: import random
   ...:
   ...: spinner.start()
   ...: for i in range(100):
   ...:     spinner.text = '{0}% Downloaded dataset.zip'.format(i)
   ...:     time.sleep(random.random())
   ...: spinner.succeed('Downloaded dataset.zip')

People to notify

@manrajgrover

[winterjung]

In this case, if you type spinner.stop() (doesn't saw but it is kept handling) and press Enter, the spinner stops. But I think you want a more elegant solution.

To solve this problem, we capture KeyboardInterrupt signal, pass to the thread and stop a task immediately. One of the solutions is to implement specific thread class inherited thread.Thread like this. Second is to using signal module. In this way code is more clear and much better but there are maybe platform-specific issues.

I used the second way to solve the problem. Please review my method.

[winterjung]

@manrajgrover Can I send a PR for review?

[manrajgrover]

@jungwinter I would need a little more time to review the methods. Apologies for the delay.

[manrajgrover]

With reference to #38, adding test case seems to fail on Appveyor. Need to find the reason behind this.