Prerequisites

Pycopine requires Python 3.2+, but may be backportet to 2.7 in the future.

Installation

Pycopine is not released yet.

(Planned) Features

• Detect and report failing services.

• Short-circuit services that fail on high load to help them recover.

• Monitor failure rates and performance metrics to detect bottlenecks.

• Manage thread pool and queue sizes on demand, at runtime, from everywhere.

• … (more to come)

Example

Lets say we want to speak to a remote service that is slow, unreliable or both:

import time
import random

def crappy_service(input):
    ''' The most useless piece of code ever.'''
    time.sleep(5)
    if 'OK' != random.choice(['OK', 'OK', 'f**ck']):
        raise RuntimeError('We broke something.')
    return input

You could throw lots of threads and try/except clauses at the problem and hope to not break the internet. Or you could use pycopine:

from pycopine import Command

class MyCommand(Command):
    ''' Does nothing with the input, but with style. '''

    def run(self, input):
        return crappy_service(input)

    def fallback(self, input):
        return input

# Run and wait for the result
result = MyCommand('input').result()

# Give up after 2 seconds
result = MyCommand('input').result(timeout=2)

# Fire and forget
MyCommand('input').submit()

# Do stuff in parallel
foo = MyCommand('input_a').submit()
bar = MyCommand('input_b').submit()
results = [foo.result(), bar.result()]

# Change your mind midway through
foobar = MyCommand('input').submit()
if foobar.wait(timeout=2):
    result = foobar.reault()
else:
    foobar.cancel(RuntimeError('No time for this sh**t'))