I am building Microservice, I have 2 project / 1 DB in Warehouse and 1 DB in Shop. When I have a new book in Warehouse I have updated DB in Shop - celery takes this task and does
Models in Warehouse and Shop it same.
I'm getting a strange error that I can't find information for.
Models:
from django.db import models
from django.urls import reverse
class Author(models.Model):
first_name = models.CharField(max_length=50)
last_name = models.CharField(max_length=50)
def __str__(self):
return f'{self.first_name} {self.last_name}'
class Genre(models.Model):
name = models.CharField(max_length=50, db_index=True)
slug = models.SlugField(max_length=50, unique=True)
class Meta:
ordering = ('name',)
verbose_name = 'genre'
verbose_name_plural = 'genres'
def __str__(self):
return self.name
def get_absolute_url(self):
return reverse('shop:book_list_by_genre', args=[self.slug])
class Book(models.Model):
author = models.ForeignKey('Author', on_delete=models.CASCADE)
genre = models.ForeignKey(Genre,
related_name='books',
on_delete=models.CASCADE)
title = models.CharField(max_length=255)
description = models.TextField(blank=True)
language = models.CharField("language", max_length=20)
pages = models.IntegerField()
image = models.ImageField(upload_to='products/%Y/%m/%d')
slug = models.SlugField(max_length=255)
price = models.DecimalField(max_digits=10, decimal_places=2)
isbn = models.CharField('ISBN', max_length=13,
unique=True)
created = models.DateTimeField(auto_now_add=True)
available = models.BooleanField(default=True)
quantity = models.IntegerField()
class Meta:
ordering = ('title',)
index_together = (('id', 'slug'),)
def __str__(self):
return self.title
def get_absolute_url(self):
return reverse('shop:book_detail',
args=[self.id, self.slug])
Celery:
from celery import shared_task
from django.core.mail import send_mail
import requests
from .models import Author, Book, Genre
@shared_task
def send_mail_task(subject, message, email):
send_mail(subject, message, email, ['[email protected]'])
@shared_task
def shop_sync():
print('Starting update from warehouse api for database')
print('Getting data from api...')
url = 'http://warehouse:8001/warehouse/authors/'
print('Clearing data...')
response_author = requests.get(url)
if response_author.status_code != 200:
return
response_data_author = response_author.json()
while 1:
for counter, data in enumerate(response_data_author['results']):
Author.objects.get_or_create(
id=data['id'],
defaults={
'id': data['id'],
'first_name': data['first_name'],
'last_name': data['last_name']
}
)
if response_data_author['next']:
response_data_author = requests.get(response_data_author['next']).json()
else:
break
url = 'http://warehouse:8001/warehouse/genres/'
print('Clearing data...')
response_genre = requests.get(url)
if response_genre.status_code != 200:
return
response_data_genre = response_genre.json()
while 1:
for counter, data in enumerate(response_data_genre['results']):
Genre.objects.get_or_create(
id=data['id'],
defaults={
'slug': data['slug'],
'name': data['name'],
}
)
if response_data_genre['next']:
response_data_genre = requests.get(
response_data_genre['next']
).json()
else:
break
url = 'http://warehouse:8001/warehouse/books/'
print('Clearing data...')
response_book = requests.get(url)
if response_book.status_code != 200:
return
response_data_book = response_book.json()
while 1:
for counter, data in enumerate(response_data_book['results']):
book, created = Book.objects.get_or_create(
id=data['id'],
defaults={
'id': data['id'],
"title": data['title'],
"description": data['description'],
"language": data['language'],
"pages": data['pages'],
"image": data['image'],
'slug': data['slug'],
"price": data['price'],
"isbn": data['isbn'],
"created": data['created'],
"available": data['available'],
"quantity": data['quantity'],
"author": Author.objects.get(id=data['author'])
}
)
if not created:
book.title = data['title']
book.description = data['description']
book.language = data['language']
book.pages = data['pages']
book.image = data['image']
book.slug = data['slug']
book.price = data['price']
book.isbn = data['isbn']
book.created = data['created']
book.available = data['available']
book.quantity = data['quantity']
book.author = Author.objects.get(id=data['author'])
book.save()
for i in data['genre']:
genre = Genre.objects.get(id=i)
book.genre.add(genre)
if response_data_book['next']:
response_data_book = requests.get(response_data_book['next']).json()
else:
break
print('Database was updated from warehouse api')
TRACEBACK:
-
Traceback (most recent call last): File "/usr/local/lib/python3.10/site-packages/celery/app/trace.py", line
450, in trace_task R = retval = fun(*args, **kwargs) File "/usr/local/lib/python3.10/site-packages/celery/app/trace.py", line
731, in protected_call return self.run(*args, **kwargs) File "/code/shop/tasks.py", line 78, in shop_sync book, created = Book.objects.get_or_create( File "/usr/local/lib/python3.10/site-packages/django/db/models/manager.py", line 85, in manager_method return getattr(self.get_queryset(), name)(*args, **kwargs) File "/usr/local/lib/python3.10/site-packages/django/db/models/query.py",
line 588, in get_or_create return self.create(**params), True File "/usr/local/lib/python3.10/site-packages/django/db/models/query.py",
line 453, in create obj.save(force_insert=True, using=self.db) File "/usr/local/lib/python3.10/site-packages/django/db/models/base.py",
line 726, in save self.save_base(using=using, force_insert=force_insert, File "/usr/local/lib/python3.10/site-packages/django/db/models/base.py",
line 763, in save_base updated = self._save_table( File "/usr/local/lib/python3.10/site-packages/django/db/models/base.py",
line 868, in _save_table results = self._do_insert(cls._base_manager, using, fields, returning_fields, raw) File "/usr/local/lib/python3.10/site-packages/django/db/models/base.py",
line 906, in _do_insert return manager._insert( File "/usr/local/lib/python3.10/site-packages/django/db/models/manager.py", line 85, in manager_method return getattr(self.get_queryset(), name)(*args, **kwargs) File "/usr/local/lib/python3.10/site-packages/django/db/models/query.py",
line 1270, in _insert return query.get_compiler(using=using).execute_sql(returning_fields) File "/usr/local/lib/python3.10/site-packages/django/db/models/sql/compiler.py", line 1416, in execute_sql cursor.execute(sql, params) File "/usr/local/lib/python3.10/site-packages/django/db/backends/utils.py", line 98, in execute return super().execute(sql, params) File "/usr/local/lib/python3.10/site-packages/django/db/backends/utils.py", line 66, in execute return self._execute_with_wrappers(sql, params, many=False, executor=self._execute) File "/usr/local/lib/python3.10/site-packages/django/db/backends/utils.py", line 75, in _execute_with_wrappers return executor(sql, params, many, context) File "/usr/local/lib/python3.10/site-packages/django/db/backends/utils.py", line 79, in _execute with self.db.wrap_database_errors: File "/usr/local/lib/python3.10/site-packages/django/db/utils.py", line
90, in exit raise dj_exc_value.with_traceback(traceback) from exc_value File "/usr/local/lib/python3.10/site-packages/django/db/backends/utils.py", line 84, in _execute return self.cursor.execute(sql, params) django.db.utils.IntegrityError: null value in column "genre_id" of relation "shop_book" violates not-null constraint DETAIL: Failing row contains (7, INFERNO, Finding himself in the most mysterious Italian town - Florence, ..., English, 472,
http://warehouse:8001/media/products/2021/09/15/cover-50.jpg,
inferno, 445.00, 9780307736925, 2021-10-19 23:38:08.910299 00, t, 8,
1, null).
CodePudding user response：
your Book model has mandatory One-to-many relation to Genre
class Book(models.Model):
genre = models.ForeignKey(Genre,
related_name='books',
on_delete=models.CASCADE)
That means you have to provide value for genre in defaults if creating new Book
book, created = Book.objects.get_or_create(
id=data['id'],
defaults={
'id': data['id'],
'genre': # value needs to be provided here
There is a code later trying to add genres
for i in data['genre']:
genre = Genre.objects.get(id=i)
book.genre.add(genre)
But that code is to late and it expects Book to Genre being Many-to-many relation when if fact Book to Genre defined as One-to-Many relation
Something will have to change either data model or synchronisation script.