Cannot get the value from dogpile.cache from different modules.

[xeon Mailinglist]

On Tuesday, December 29, 2015 at 5:15:24 PM UTC, Mark Lawrence wrote:
> On 29/12/2015 15:20, xeon Mailinglist wrote:
> > On Tuesday, December 29, 2015 at 11:16:10 AM UTC, xeon Mailinglist wrote:
> >> 1. How do I create a global variable that can be accessed by all classes?
> >>
> >> 2. I am using `dogpile.cache` to store data in the cache [1], but if I set and get the same key from different modules, I don't get the value. Here is an example in [2]. The value than I get is `NO_VALUE.NO_VALUE`. Why this happens?
> >>
> >> setter is the setter.py
> >> getter is the getter.py
> >> Memoize is the file in [1].
> >>
> >>
> >> [1] my dogpile class `Memoize.py`
> >>
> >>      from dogpile.cache import make_region
> >>
> >>      region = make_region().configure('dogpile.cache.memory')
> >>
> >>      def save(key, value):
> >>        """
> >>        general purpose method to save data (value) in the cache
> >>
> >>        :param key (string) key of the value to be saved in cache
> >>        :param value (any type) the value to be saved
> >>        """
> >>        region.set(key, value)
> >>
> >>
> >>      def get(key):
> >>        """
> >>        general purpose method to get data from the cache
> >>
> >>        :param key (string) key of the data to be fetched
> >>        :return value (any type) data to be returned from the cache
> >>        """
> >>        return region.get(key)
> >>
> >>
> >> [2] My python example
> >>
> >> `setter.py`
> >>
> >>      def myset(value):
> >>        Memoize.save("myvalue", value)
> >>
> >> `getter.py`
> >>
> >>     def myget():
> >>        return Memoize.get("myvalue") <- this value is NO_VALUE. NO_VALUE
> >>
> >> My class:
> >>
> >>      setter.myset(123)
> >>      getter.myget()
> >
> > The idea that I get from dogpile, is that in each module (getter.py, or setter.py) there is a dictionary where the values are stored in the backend. Hence, getter.py has its dictionary and setter.py has its dictionary also. In the end, there is not a single dictionary where all the values should be put. And I want a single dictionary.
> >
> 
> Then put everything in one file.  Three files for the amount of code you 
> show above is nonsensical.  You might like to read 
> http://dirtsimple.org/2004/12/python-is-not-java.html and in response to 
> that http://dirtsimple.org/2004/12/java-is-not-python-either.html
> 
> -- 
> My fellow Pythonistas, ask not what our language can do for you, ask
> what you can do for our language.
> 
> Mark Lawrence

Here is the full class that I use to store the data.

from dogpile.cache import make_region


# my_dictionary = {}
region = make_region().configure('dogpile.cache.memory')
# arguments={"cache_dict":my_dictionary})
class Cache:

    @staticmethod
    def save(key, value):
        """
        general purpose method to save data (value) in the cache

        :param key (string) key of the value to be saved in cache
        :param value (any type) the value to be saved
        """
        region.set(key, value)

    @staticmethod
    def get(key):
        """
        general purpose method to get data from the cache

        :param key (string) key of the data to be fetched
        :return value (any type) data to be returned from the cache
        """
        return region.get(key)


    @staticmethod
    def get_or_create(key):
        """
        General purpose method to get data from the cache. If the value does not exist, it creates a list

        :param: key (string) key of the data to be fetched
        :return value (any type) data to be returned from the cache
        """
        return region.get_or_create(key, list)

    @staticmethod
    def set_job_predictions(rank_list):
        Cache.save("job_predictions", rank_list)

    @staticmethod
    def get_job_predictions():
        return Cache.get("job_predictions")