Exception: Ruleset with {name of ruleset} already registered

[lechiffre]

Hi,

thanks for great module. I am trying to run in Python your "Hello world" example. I cannot run it more than once :(. Or I cannot run any other ruleset with different name. The exception is keep referring to the first run ruleset and any other rule I try to run does not work anymore and exception is keep referring to first rule set. See the exception below.

1) This is the response after I run the Hello world for the first time:

Hello World
{'sid': '0', 'id': 'sid-0', '$s': 1}

2) This is the exception I am getting after second run:

---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
<ipython-input-2-bcb2fdd60e15> in <module>
      8         print('Hello {0}'.format(c.m.subject))
      9 
---> 10 post('test', { 'subject': 'World' })

~/anaconda3/lib/python3.7/site-packages/durable/lang.py in post(ruleset_name, message, complete)
    664 
    665 def post(ruleset_name, message, complete = None):
--> 666     return get_host().post(ruleset_name, message, complete)
    667 
    668 def post_batch(ruleset_name, messages, complete = None):

~/anaconda3/lib/python3.7/site-packages/durable/lang.py in get_host()
    659         ruleset_definitions[full_name] = ruleset_definition
    660 
--> 661     _main_host.register_rulesets(ruleset_definitions)
    662     _rulesets = {}
    663     return _main_host

~/anaconda3/lib/python3.7/site-packages/durable/engine.py in register_rulesets(self, ruleset_definitions)
    784         for ruleset_name, ruleset in rulesets.items():
    785             if ruleset_name in self._ruleset_directory:
--> 786                 raise Exception('Ruleset with name {0} already registered'.format(ruleset_name))
    787             else:
    788                 self._ruleset_directory[ruleset_name] = ruleset

Exception: Ruleset with name test already registered

Any ideas what can I do with that? Thanks a million

[jruizgit]

Hi, thanks for asking the question. Would you mind pasting the exception that led to the exception?

[lechiffre]

Hi, yes. If I run the code below in jupiter notebook snippet twice, the exception above will raise. After that any other ruleset I would run would still return the exactly same exception as described above.

Here is what I run:

from durable.lang import *

with ruleset('test'):
    # antecedent
    @when_all(m.subject == 'World')
    def say_hello(c):
        # consequent
        print('Hello {0}'.format(c.m.subject))

post('test', { 'subject': 'World' })

Thanks for getting back to me.

[lechiffre]

Is it possible that this is an error that appears only in Jupyte notebook?

[jruizgit]

Hi, I'm guessing the notebook is running the code in the same python process. Two rulesets with the same name cannot exist in the same process. If you want to try a different ruleset, I suggest you use a different name. If you want to try the same ruleset, you don't need to declare it again. You just need to post events and assert facts.

[staylorx]

I've had the same experience. Not an error, per se, and your explanation above is clear. However, to allow for some idempotence, is there a way to reset the rules engine in code? If you've already got a way to clear rulesets, I just couldn't find it in the docs easily. So, apologies if you've already done this.

Duplicating the copy from above but with an imagined clear or reset:

from durable.lang import *

#I would expect this to clear the ruleset and return successfully even if the ruleset is already clear or doesn't exist:
ruleset('test').clear()  # or .reset() 

# then all should move along succesfully
with ruleset('test'):
    @when_all(m.subject == 'World')
    def say_hello(c):
        print ('Hello {0}'.format(c.m.subject))

post('test', { 'subject': 'World' })

[PrashanthK23]

Hi @staylorx did you find any solution for reset/clear ? I have a business need to do that

[PrashanthK23]

Hi @jruizgit,
1) Can we able to clear/reset the ruleset (as I want to update the ruleset regularly by maintaining the same ruleset name) 2) Do we have any method to check a ruleset is already exists or not ?

[jadami10]

For those looking for an easy way to test this in a notebook, you can clear the ruleset directory before recreating the rule. I use this to keep altering the say_hello function and just rerun the cell.

from durable.lang import ruleset, when_all, m, post, _main_host

if _main_host is not None:
    _main_host._ruleset_directory.clear()

with ruleset('test'):
    @when_all(m.subject == 'World')
    def say_hello(c):
        print ('Hello {0}'.format(c.m.subject))

You could also use that same method to check if rules exist already. I'd be happy to contribute a change to allow querying and overriding the _ruleset_directory if @jruizgit wants that functionality.

[jruizgit]

Hi, thanks for the suggestion. I'm sorry I missed this comment a while back. Please feel free to send me a pull request. Otherwise I'm planning to add the functionality in the next couple of weeks.

[harsha20-creator]

@jruizgit wanted to check on the above on how to clear the rule if that has already been run. I have a rule and when that rule triggers within few seconds when i trigger the same rule with different request. i get the above error.

I was trying to do something above but _ruleset_directory being a protected variable is not exposed to us. Appreciate if you can provide some insight on this one.

I tried something like this

if get_host() is not None and get_host().get_ruleset("test") is not None: get_host().get_ruleset("test").clear()

but still i wasn't able to get this cleared and ran into this error 'Exception: Ruleset with name test already registered\n

[ChristopherCorvo]

@jruizgit Also checking to see if the feature to update or clear an established rule has been created. I see that you were talking about developing this feature back in 2020. Curious if it was created or if there is a reason for why this feature should not be used. Thanks

[alifim]

I've managed to do it by adding this before creating ruleset. basically, it removes the ruleset from the ruleset dictionary

from durable.lang import ruleset, when_all, m, post, get_host

ruleset_name = "test"
host = get_host()

if ruleset_name in host._ruleset_directory.keys():
        host._ruleset_directory.pop(ruleset_name, None)

with ruleset(ruleset_name):
    ...