bgtasks

bgtasks is python library for dealing with data exchange between micro services using rabbitmq protocol. Moreover, you can use it as trigger for events which belongs to another services.

Installation

Use the package manager pip to install bgtasks.

pip install bgtasks

Configuration

settings.py

AMQP = {
    'USERNAME': 'guest',
    'PASSWORD': 'guest',
    'VHOST': '/',
    'HOST': 'localhost',
    'PORT': 5672,
    'RPC_SLEEP_TIME': 0.005,
    'RPC_TIMEOUT': 5,
}

Default values

'RPC_TIMEOUT': 60
'RPC_SLEEP_TIME': 0.05,

Usage

Creating bgtask view for handle actions through route

app1 tasks.py

from bgtasks import rpc_tasks
from bgtasks import Response

@rpc_tasks('message')
def handle(data):
    print(data)
    return Response('I received your message %s' % data)

To get response

from bgtasks import RPCClient

rpc_client = RPCClient()

try:
    response = rpc_client.call('message', 'Hi')
    print(response)
except TimeoutError:
    print('Service is not responding')

In order to avoid conflicts between remote procedure calls you should pass parameters explicitly with keywords

To run rpc task run command below

python manage.py tasks

RestFramework

service1

Model

models.py

from django.db import models

class Category(models.Model):
    name = models.CharField(max_length=255)

In this case your add should receive arguments' list with explicit variable name ids

Tasks

tasks.py

from bgtasks import rpc_tasks
from bgtasks import Response
from bgtasks import serializer_class
from testapp.models import Category
from rest_framework import serializers


class CategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = Category
        fields = ('id', 'name')


@rpc_tasks('add')
@serializer_class(CategorySerializer, many=True)
def handle(serializer):
    serializer.save()
    return Response(serializer.data)


@rpc_tasks('get')
@serializer_class()
def handle(serializer):
    queryset = Category.objects.filter(id__in=serializer.validated_data['ids'])
    serializer = CategorySerializer(queryset, many=True)
    return Response(serializer.data)

service2

app1 models.py

from django.db import models
from bgtasks.models import RemoteField

class Product(models.Model):
    name = models.CharField(max_length=255)
    category = RemoteField() # in our case, it is in another service id

RemoteField

from rest_framework import serializers
from bgtasks.rest_framework.fields import RemoteField
from app1.models import Product


class ProductSerializer(serializers.ModelSerializer):
    category = RemoteField(route='get')

    class Meta:
        model = Product
        fields = ('id', 'name', 'category', )

Format

And make sure that returned response should be formed as below format.

{
    'status': 'success/fail',
    'data': [
        {
            'id': 1,
            # 'data'
        },
        {
            'id': 2,
            # data
        }
    ]
}

Handling list serializer

In order to avoid from sending many rpc requests at first level of serializer we added RPCSerializerMixin

from bgtasks import RemoteField
from bgtasks.rest_framework.serilaizers import RPCSerializerMixin
from rest_framework import serializers
from app1.models import Product

class ProductListSerializer(RPCSerializerMixin, serializers.ModelSerializer):
    category = RemoteField(route='get')

    class Meta:
        model = Product
        fields = '__all__'

users = Product.objects.all()
serializer = ProductListSerializer(users, many=True)
print(serializer.data)

It will send to route one request with gathered pks in body as [1,2,3,4,5], after which will be iterated to merge current serializer data which maps to id field in rpc response

Output

[
    {
        'id': 1,
        'name': 'IPhone',
        'category': {
            'id': 5,
            'name': 'Phone',
        }
    },
    {
        'id': 2,
        'name': 'LG Smart Tv',
        'category': {
            'id': 3,
            'name': 'TV',
        }
    },
]

Merge methods

To handle many=True in serializer we introduce RPCSerializerMixin which uses merge functions. You can import them as below, and to understand can look to function profile.

from bgtasks.utils.merge import merge, merge_dict, merge_obj

Testing

Add ENVIRONMENT = 'test' on settings.py in order to imitate response from another service

import json
from django.test import TestCase
from django.test import Client
from bgtasks import rpc_tasks
from bgtasks import RPCClient
from bgtasks import SUCCESS
from bgtasks.amqp import register_tasks


@rpc_tasks('user.add')
def add_user(data):
    return 1

class RPCTestCase(TestCase):
    def setUp(self):
        register_tasks() # If you want to run your tasks to test them out, not only rpc tasks which are registered inside of your test file

    def test_add_user(self):
        data = {'username': 'john', 'password': 'smith'}
        c = Client()
        response = c.post('/user/add/', data)
        data = json.loads(response.content)
        self.assertEqual(response.status_code, 201)
        self.assertEqual(data['user_id'], 1)


    def test_your_tasks(self):
        data = RPCClient().call('mytasks', {})
        self.assertEqual(data['status'], SUCCESS)

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

How to deploy

Create config file in home directory ~/.pypirc

[distutils] 
index-servers=pypi
[pypi] 
repository = https://upload.pypi.org/legacy/ 
username = myrubapa

After run command for build and deploy

python3 setup.py sdist bdist_wheel
python3 -m twine upload dist/*

for more detail read packaging-projects

License

MIT