from __future__ import print_function
from IPython.lib import backgroundjobs as bg

import sys
import time

def sleepfunc(interval=2, *a, **kw):
    args = dict(interval=interval,
                args=a,
                kwargs=kw)
    time.sleep(interval)
    return args

def diefunc(interval=2, *a, **kw):
    time.sleep(interval)
    raise Exception("Dead job with interval %s" % interval)

def printfunc(interval=1, reps=5):
    for n in range(reps):
        time.sleep(interval)
        print('In the background...', n)
        sys.stdout.flush()
    print('All done!')
    sys.stdout.flush()

jobs = bg.BackgroundJobManager()

# Start a few jobs, the first one will have ID # 0
jobs.new(sleepfunc, 4)
jobs.new(sleepfunc, kw={'reps':2})
jobs.new('printfunc(1,3)')

# This makes a couple of jobs which will die.  Let's keep a reference to
# them for easier traceback reporting later
diejob1 = jobs.new(diefunc, 1)
diejob2 = jobs.new(diefunc, 2)

jobs.status()

jobs[0].result
j0 = jobs[0]
j0.join?

print "Status of diejob1:", diejob1.status
diejob1.traceback()  # jobs.traceback(4) would also work here, with the job number

jobs.traceback()

jobs.flush()

jobs.status()

j = jobs.new(sleepfunc, 2)
print("Will wait for j now...")
sys.stdout.flush()
j.join()
print("Result from j:")
j.result