CODEWITHSUNDEEP
pythonpython-2.7google-app-enginegoogle-cloud-datastoreapp-engine-ndb
vkb
vkb

Reputation: 458

GAE datastore query ConjunctionNode error

I have a ndb model in datastore with two fields - expired and expiry besides other details such as bookname, author etc. 

class Books(ndb.Model):  
     expiry = ndb.IntegerProperty() #epoch
     expired = ndb.BooleanProperty(default=False) # set True if expiry < curr_time

I have written cron.yaml and cron.py to mark expired=True for finding the books where the expiry < curr_time.

Following is my cron.py snippet:

    from google.appengine.api import search
    import logging
    from models.books import Books
    from google.appengine.ext import ndb
    import time

    def deleteindex(cls):
           curr_time = int(time.time()) + 60
           #find the books which have expired but not marked expired. 
           expired_books = Books.query(ndb.AND(Books.expiry < curr_time, not Books.expired)) 
           print expired_books

However, I am getting error :

File "/home/hduser/Documents/GCP/book-shelf453/default/app/cron.py", line 16, in deleteindex

expired_books = Books.query(ndb.AND(Books.expiry < curr_time, not Books.expired)) File "/home/hduser/Documents/GCP/google-cloud-sdk/platform/google_appengine/google/appengine/ext/ndb/query.py", line 583, in new ' received a non-Node instance %r' % node)

TypeError: ConjunctionNode() expects Node instances as arguments; received a non-Node instance False

I am not sure about the issue here. Please suggest ! Thanks!

Upvotes: 1

Views: 151

Answers (1)

snakecharmerb
snakecharmerb

Reputation: 55894

ndb query filters must consist of comparisons between a model property and a value - for example between Books.expiry and an int.

not Books.expired is not such a comparison, and this is the cause of the error.

Instead of negating Books.expired, compare it to a boolean.

This should work:

expired_books = Books.query(ndb.AND(Books.expiry < curr_time, Books.expired != False))

Upvotes: 1

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