django-nats-client 0.3.4

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Django NATS

Features

• Wrapper of NATS's nats-py
• Django management command to listen for incoming NATS messages
• Automatically serialize/deserialize message from/to JSON format
• Easy-to-call method for sending NATS messages

Installation

pip install django-nats-client

Setup

1. Add nats_client into INSTALLED_APPS

   # settings.py
   
   INSTALLED_APPS = [
       ...
       'nats_client',
   ]
   

2. Put NATS connection configuration in settings

   # settings.py
   
   NATS_OPTIONS = {
       'servers': ['nats://localhost:4222'],
       'max_reconnect_attempts': 2,
       'connect_timeout': 1,
       ...
   }
   NATS_LISTENING_SUBJECT = 'default'
   

Usage

Listen for messages

1. Create a new callback method and register

   # common/nats.py
   
   import nats_client
   
   @nats_client.register
   def get_year_from_date(date: str):
       return date.year
   
   # custom name
   @nats_client.register('get_current_time')
   def current_time():
       return datetime.datetime.now().strftime('%H:%M')
   
   # without decorator
   def current_time():
       return datetime.datetime.now().strftime('%H:%M')
   nats_client.register('get_current_time', current_time)
   

2. Import previously file in ready method of your apps.py

   # common/apps.py
   
   class CommonConfig(AppConfig):
       ...
   
       def ready(self):
           import common.nats
   

3. Run listener management command

   python manage.py nats_listener
   
   # or with autoreload enabled (suite for development)
   python manage.py nats_listener --reload
   

Sending message

import nats_client

arg = 'some arg'
nats_client.send(
   'subject_name',
   'method_name',
   arg,
   keyword_arg=1,
   another_keyword_arg=2,
)

Examples

import nats_client

nats_client.send('default', 'new_message', 'Hello, world!')
nats_client.send('default', 'project_created', 1, name='ACME')

Request-Reply

import nats_client

arg = 'some arg'
nats_client.request(
   'subject_name',
   'method_name',
   arg,
   keyword_arg=1,
   another_keyword_arg=2,
)

Examples

import nats_client

year = nats_client.request('default', 'get_year_from_date', datetime.date(2022, 1, 1))  # 2022
current_time = nats_client.request('default', 'get_current_time')  # 12:11

Settings

Key	Required	Default	Description
NATS_OPTIONS	Yes		Configuration to be passed in nats.connect()
NATS_LISTENING_SUBJECT	No	'default'	Subject for registering callback function
NATS_REQUEST_TIMEOUT	No	1	Timeout when using request() (in seconds)

Development

Requirements

• Docker
• Python
• Poetry

Linting

make lint

Testing

make test

Fix Formatting

make yapf