App engine read DataStore data between modules

Question

I have a app divided in 5 modules (see my beautiful ascii art) Each have their own directory, just like this structure

      AppEngine App     <--Here's the dispatch.yaml
 ---------------------
 |    |    |    |    |
 |    |    |    |    |
Mod1 Mod2 Mod3 Mod4 Mod5
 ^                     ^
 \__Here's the models  |__ Here i wanna read the models
    .py file 
    with the __init__.py

The NDB models are defined in one module (mod1 by example) and i wanna read some data in the Mod5, the official documentation says that's posible, but i can't do it. I'm importing the model in this ways

#this is in mod5 py file
import Mod1.models # No module named Mod1.models
from Path.Mod1 import models  #No module named Path.Mod1 
from Mod1 import models  #No module named Mod1 
from Mod1.models import specific_model  #No module named Mod1.models 
from Path.models import specific_model  #No module named Path.models

I change the --storage_path setting to each module to be able tu run all modules at the same time in the launcher, i think that could be the problem. But if i leave the same directory how can run at the same time all the modules (i got "OperationalError: database is locked" error) Any clue here?

I remove the storage_path, and the DB file is in the same path, but the problem persist, so this is not the cause — Kristian Damian, Oct 16 '14 at 23:17

score 2 · Answer 1 · edited May 23 '17 at 11:46

According to this answer from google cloud support there are 3 ways.

Symbolic link to a single file with definitions... this can get sticky when using different OSs. According to this SO answer linked in Dan's comment, GAE copies the contents of a directory to the target directory.
Write a build script to copy model definitions to each service.
Manually copy model definitions to each service.

score 1 · Answer 2 · edited Oct 17 '14 at 06:25

1

Based on the given information, I am wondering if you are missing the __init__.py file in each of the subdirectories. This will allow the Python modules to be usable in those directorie. See https://docs.python.org/2/tutorial/modules.html#packages

Can you share the file structure in the directories?

edited Oct 17 '14 at 06:25

Lipis

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answered Oct 17 '14 at 03:03

ChrisC73

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i already have the __init__.py file in each sub-directory but had not realized it that doesn't have the corresponding .pyc, so i think that app engine is ignoring it – Kristian Damian Oct 17 '14 at 14:00

Kristian Damian · Accepted Answer · 2014-10-17T22:06:35.893

I found a answer, not ideal, but works.

If i clone (A.K.A copy-paste) the models.py file in the Mod5 folder and remove the --storage_path setting (the db is shared in the same temp folder in the develop server) i can read the data stored.

Obviously the models needs to be sync in EVERY change, but at least i can move forward in my code

The directory structure stay as follows:

-- Main (with the dispatch.yaml)
 |__ Mod1
 |      |__ model.py
 |      |__ app.yaml
 |      |__ specificMod1Code.py
 |      |______ Templates
 |      |______ js
 |      |______ css
 |      |______ img
 :
 :
 :
 |__ Mod5
        |__ model.py #equal that mod1
        |__ app.yaml #with the mod5 instace and stuff
        |__ specificMod5Code.py
        |______ Templates
        |______ js
        |______ css
        |______ img

To run all the modules at the same time it's necesary run the dev_appserver command in the root directory of the app (source)

python dev_appserver.py mod1\app.yaml mod2\app.yaml mod3\app.yaml mod4\app.yaml mod5\app.yaml

Runnind in this URL's

Mod1=> localhost:8080

Mod2=> localhost:8081

Mod3=> localhost:8082

Mod4=> localhost:8083

Mod5=> localhost:8084

App engine read DataStore data between modules

3 Answers3