Module utils

Decorator for printing execution time (in mins) of a function
Optionally takes a user-friendly msg as argument. This msg will
appear in the sentence "[msg] took XXX mins". If no msg is specified,
msg will default to the decorated function's name. e.g:

@print_timing
def myfunc():
    print 'Running myfunc'
>>> myfunc()
Running myfunc
myfunc took 0.000 mins

@print_timing('My function')
def myfunc():
    print 'Running myfunc'
>>> myfunc()
Running myfunc
My function took 0.000 mins

Check if bucket_name is a valid S3 bucket name (as defined by the AWS
docs):

1. 3 <= len(bucket_name) <= 255
2. all chars one of: a-z 0-9 .  _ -
3. first char one of: a-z 0-9
4. name must not be a valid ip

Check if image_name is a valid AWS image name (as defined by the AWS docs)

1. 3<= len(image_name) <=128
2. all chars one of: a-z A-Z 0-9 ( ) . - / _

Returns command to execute python script as a one-line python program

e.g.

    import os
    script = '''
    import os
    print os.path.exists('hi')
    '''
    os.system(make_one_liner(script))

Will print out:

    <module 'os' from ...>
    False

Returns generator of all permutations of a

The following code is an in-place permutation of a given list, implemented
as a generator. Since it only returns references to the list, the list
should not be modified outside the generator. The solution is
non-recursive, so uses low memory. Work well also with multiple copies of
elements in the input list.

Retrieved from:
    http://stackoverflow.com/questions/104420/         how-to-generate-all-permutations-of-a-list-in-python

Checks that all commands in the programs list exist. Returns True if all commands exist and raises exception.CommandNotFound if not.

Returns the path to the program provided it exists and is on the system's PATH

retrieved from code snippet by Jay:

http://stackoverflow.com/questions/377017/ test-if-executable-exists-in-python

Convenience wrapper around inspect.getargspec

Returns a tuple whose first element is a list containing the names of all required arguments and whose second element is a list containing the names of all keyword (optional) arguments.

iterate through 'chunks' of a list. final chunk consists of remaining elements if items does not divide len(ls) evenly.

items - size of 'chunks'