CODEWITHSUNDEEP
pythonmongodbpython-3.xmongoengine
Jhorra
Jhorra

Reputation: 6321

Error trying to import between python files

I have a basic parser app I'm building in Python. I monitors a folder and imports files when they are dropped there. I have a MongoDB that I'm trying to save the imports to. There's almost nothing to it. The problem happens when I try to include one of my class/mongo-document files. I'm sure it's a simple syntax issue I don't understand. I have all my requirements installed, and I'm running this in an virtual env. This is my first python app though, so it's likely something I'm not seeing.

My file structure is

application.py
requirements.txt
__init__.py
-services
   parser.py
   __init__.py
-models
   hl7message.py
   __init__.py

Here is application.py

from mongoengine import connect
import os, os.path, time
from services import parser

db = connect('testdb')
dr = 'C:\\Imports\\Processed'

def processimports():
    while True:
        files = os.listdir(dr)
        print(str(len(files)) + ' files found')
        for f in files:
            msg = open(dr + '\\' + f).read().replace('\n', '\r')
            parser.parse_message(msg)

        print('waiting')
        time.sleep(10)

processimports()

requirements.txt

mongoengine
hl7

parser.py

import hl7
from models import hl7message

def parse_message(message):
    m = hl7.parse(str(message))
    h = hl7message()

hl7message.py

from utilities import common
from application import db
import mongoengine

class Hl7message(db.Document):
    message_type = db.StringField(db_field="m_typ")
    created = db.IntField(db_field="cr")
    message = db.StringField(db_field="m")

If I don't include the hl7message class in the parser.py it runs fine, but as soon as I include it I get the error, so I'm sure it has something to do with that file. The error message though isn't to helpful. I don't know if I've got myself into some kind of include loop or something.

Sorry, stack trace is below

Traceback (most recent call last):
  File "C:/OneDrive/Dev/3/Importer/application.py", line 3, in <module>
    from services import parser
  File "C:\OneDrive\Dev\3\Importer\services\parser.py", line 2, in <module>
    from models import hl7message
  File "C:\OneDrive\Dev\3\Importer\models\hl7message.py", line 2, in <module>
    from application import db
  File "C:\OneDrive\Dev\3\Importer\application.py", line 23, in <module>
    processimports()
  File "C:\OneDrive\Dev\3\Importer\application.py", line 17, in processimports
    parser.parse_message(msg)
AttributeError: module 'services.parser' has no attribute 'parse_message'

Upvotes: 3

Views: 162

Answers (1)

Gribouillis
Gribouillis

Reputation: 2220

This is a circular import issue. Application.py imports parser, which imports h17 which imports h17message, which imports application which runs processimports before the whole code of the parser module has been run.

It seems to me that service modules should not import application. You could create a new module common.py containing the line db = connect('testdb') and import db from common both in application.py and in h17message.

Upvotes: 2

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