Consistence problem on delete activity posts

Currently there is a nasty problem when we delete Activity Posts: we delete the Activity Posts, but we don't delete its reference in its parent Activity Record's activity_posts field. And then, when we request the said Activity Record, it tries to access to the Activity Post to calculate the metrics, and as the post doesn't exist anymore, we get an internal server error.

I see three possible solutions :

In the Delete Activity Post endpoint we modify also the parent Activity Record to delete the Activity Post reference

Not to use the said reference anymore, as we don't need it really... Right now we calculate the metrics like this:

def metric_reached(self):
   total_reached = 0

   if len(self.activity_posts) == 0:
       return total_reached

   for post_id in self.activity_posts:
       post_key = ndb.Key(ActivityPost, int(post_id))
       activity_post = post_key.get()
       total_reached += activity_post.metric_reached
   return total_reached

We could instead directly query the Activity post to get those whose the parent is the current Activity Record:

def metric_reached(self):
   total_reached = 0

   for activity_post in ActivityPost.query(ActivityPost.id == self.id) :
       total_reached += activity_post.metric_reached
   return total_reached

Model Activity Posts as Structured Properties If I understand correctly, every Activity Post is always associated to one and only one Activity Record, i.e. they are not full-fledged entities.

I'm not an expert on Google API Engine, but according to the reference they seem a good candidate for be modelled as Structured Properties instead of Entities.

That would make some things way easier. If Activity Post were Structured Properties instead of Entities, the consistence problem would disappear by itself...

I think I solved this in the current code deployed this morning after your post.
We can think about the benefit of accessing the posts independently for batch processing of metric updates and whether going through Activity Records is a pain.

Patrick Martinent

On 17 August 2016 at 04:18, Horacio Gonzalez notifications@github.com wrote:

If I understand correctly, every Activity Post is always associated to one and only one Activity Record, i.e. they are not full-fledged entities.

I'm not an expert on Google API Engine, but according to the reference https://cloud.google.com/appengine/docs/python/ndb/entity-property-reference#structured they seem a good candidate for be modelled as Structured Properties instead of Entities.

That would make some things way easier. Right now wer have a nasty consistence problem: when we delete an Activity Record, we must delete the associated activity posts (this is done in the current version), and when we delete an Activity Post we should delete the reference to the post in the parent Activity Record (and it isn't done in current version, generating nasty errors 500 when we request again the Activity Record...).

If Activity Post were Structured Properties instead of Entities, the consistence problem would disappear by itself...

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Yeas, the problem was solved, I forgot to close this one :)

About accessing the posts independently, yeah, it could be a need. But with the Structured properties it could be done almost as easily.

On Wed, Aug 17, 2016 at 8:30 PM, Patrick Martinent <notifications@github.com

wrote:

I think I solved this in the current code deployed this morning after your post.

We can think about the benefit of accessing the posts independently for batch processing of metric updates and whether going through Activity Records is a pain.

Patrick Martinent

On 17 August 2016 at 04:18, Horacio Gonzalez notifications@github.com wrote:

If I understand correctly, every Activity Post is always associated to one and only one Activity Record, i.e. they are not full-fledged entities.

I'm not an expert on Google API Engine, but according to the reference https://cloud.google.com/appengine/docs/python/ndb/ entity-property-reference#structured they seem a good candidate for be modelled as Structured Properties instead of Entities.

That would make some things way easier. Right now wer have a nasty consistence problem: when we delete an Activity Record, we must delete the associated activity posts (this is done in the current version), and when we delete an Activity Post we should delete the reference to the post in the parent Activity Record (and it isn't done in current version, generating nasty errors 500 when we request again the Activity Record...).

If Activity Post were Structured Properties instead of Entities, the consistence problem would disappear by itself...

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Consistence problem on delete activity posts #29