Library provides tools for:
- Publisher/Subscription pattern
- Sending async command
- REST API
pip install git+https://github.com/ksinn/django-microservices-communication
In requirements.txt file
...
Django==4.2
git+https://github.com/ksinn/django-microservice
8000
s-communication
django-cors-headers==3.14.0
...Installation in Docker If pip install execute in docker, you require git in image.
Add 'services_communication' to your INSTALLED_APPS setting.
INSTALLED_APPS = [
...
'services_communication',
]Any global settings are kept in a single configuration dictionary named MICROSERVICES_COMMUNICATION_SETTINGS. Start off by adding the following to your settings.py module:
MICROSERVICES_COMMUNICATION_SETTINGS = {
'APP_ID': 'my-service',
'BROKER_CONNECTION_URL': 'amqp://guest:guest@localhost:5672',
# or set as connection params dict
'BROKER_CONNECTION_PARAMETERS': {
'host': 'localhost',
'port': 5672,
'virtual_host': None,
'username': 'guest',
'password': 'guest',
# Instead username and password you may set pika credentials object
'credentials': pika.PlainCredentials('guest', 'guest')
},
'QUEUE': 'my-queue',
'EXCHANGES': [
'my-exchange1',
('my-other-exchange', 'fanout'),
'exchange3',
],
'BINDS': [
('my-exchange1', 'event.*'),
'my-other-exchange',
],
'REST_API_HOST': 'http://api.example.com',
'REST_API_AUTH_URL': 'api/v1/login',
# Set auth request body
'REST_API_CREDENTIAL': {
'login': 'sarvar',
'password': 'sarvar',
},
# Or username and password, if filed named as 'username' and 'password'
'REST_API_USERNAME': 'myusername',
'REST_API_PASSWORD': '12345',
# Set True for use future event
'PUBLISHER_FUTURE_EVENT_ENABLE': False,
}Defaults:
- exchange type - topic
- bind routing key - '#'
Run consumer
python manage.py runconsumer
Write logical consuming function in file 'consumers.py' in django app
some_project/
| some_project/
| settings.py
| urls.py
| some_app/
| __init__.py
| admin.py
| apps.py
| consumers.py <----
| models.py
| tests.py
| viwes.py
| some_other_app/
| __init__.py
| admin.py
| apps.py
| consumers.py <----
| models.py
| tests.py
| viwes.py
Consumer function must be registered in message router. Basic consumer function mast accept 2 positional arguments: routing key and message body.
Example consumers.py file:
from services_communication.consumer import message_router
@message_router.consumer('my-exchange1', 'event.update')
@message_router.consumer('my-exchange1', 'event.create')
@message_router.consumer('my-other-exchange') # For get all routing keys
@message_router.consumer() # For get all exchange (default consumer)
def stupid_consume_function(routing_key, body):
print(routing_key, body)
@message_router.default_consumer # For get message not routed to other consumers
def stupid_consume_function(routing_key, body):
print(payload)
If you want to consume aggregate event, use decorator @event_consumer and after then consumer function mast accept only on positional argument event payload and other event data as kwargs Example consumers.py file:
from services_communication.consumer import message_router
@message_router.consumer('my-exchange1', 'event.update')
@message_router.consumer('my-exchange1', 'event.create')
@message_router.consumer('my-ether_exchange') # For get all routing keys
@event_consumer
def stupid_consume_function(payload, **kwargs):
print(payload)
Or user devconsumer for auto reloading on change files
Publishing in transaction
For publish event happened with aggregate in transaction use publish_aggregate_event
from services_communication.publisher import publish_aggregate_event
def update_user_name(user, new_name):
user.name = new_name
user.save()
publish_aggregate_event(
aggregate='user',
event_type='update.base',
payload=build_user_data(user),
)This function save event data in db table. Then publisher process will read the event from the table and publish it to the broker in exchange same as aggregate name with routing key same as event type, event_type and body:
{
"eventId": "2",
"eventTime": "2023-06-02T10:58:58.340174Z",
"eventType": "update.base",
"aggregate": "user",
"payload": {
...
},
}Scheduling future event (in transaction)
Work the same as regular events, but you can specify a time (in the future) when the event will be sent. Tags can be used to later cancel an event. Tag values are cast to string and value 1 equals '1', but not equals True! Need PUBLISHER_FUTURE_EVENT_ENABLE setting in True.
from services_communication.publisher import publish_future_aggregate_event, cancel_future_aggregate_event
def registrate_user(user):
....
user.save()
# remind the user to set a photo
publish_future_aggregate_event(
aggregate='user',
event_type='remind.photo',
event_time=now() + timedelta(seconds=delay),
payload=build_user_data(user),
tags={'user_id': user.id, 'any_other_tag': 'any_value'}
)
def set_user_photo(user, photo):
user.photo = photo
user.save()
# cancel remind
cancel_future_aggregate_event(
aggregate='user',
event_type='remind.photo',
tags={'user_id': user.id}
)Run publisher process
python manage.py runpublisher
Or user devpublisher for auto reloading on change files
A command is a way of telling remote service to do something without waiting for a response from it.
For send command immediately, without regard to transactionality, use send_command with service name and payloads as arguments.
You can set timeout in seconds for command executing, this means that the executor of the command should not execute it if the specified time has passed since the time it was sent (called send_command function).
from services_communication.call import send_command
send_command(
'sms',
{
'phone': '998990000000',
'text': 'Hello world!',
}
)If remote service has any commands, you may want to use optional argument command_name.
For request endpoint use method functions from rest_api package.
from services_communication.rest_api import get, post, head, delete
from services_communication.rest_api.formatter import full_response
first_subject = get('api/v1/subjects/1') # return only response body as dict
first_subject = get(
'api/v1/subjects',
params={
'page': 2,
'size': 20,
},
) # sending query params
response = get('api/v1/subjects/1', response_formatter=full_response) # return response object
new_subject = post(
'api/v1/subjects',
json={
'name': 'My new subject',
'order': 5,
},
) # sending request bodyIn all methods function you can send additional keyword argument, it was sent to request.
For formatting request and response uoy can send custom function as request_formatter and response_formatter keyword arguments.
request_formatter will be applied to other request arguments(params, json, data).
response_formatter will be applied to response and it result be returned from method.
By default:
- get, post, delete methods return response.json
- head method return full response
- 2.5.x
2.5.0 - Atomic sending command
- 2.4.x
2.4.3 - Add put and patch api helper methods
2.4.1 - Fix: add pytz requirements
2.4.0 - Add future events
- 2.3.x
2.3.8 - Fix: add pytz requirements
2.3.6 - Add extra host param for rest api
2.3.5 - Fix loading module with consumers
2.3.4 - Fix logging configration
2.3.3 - Fix consumer: down on db connection error
2.3.1 - Allow set broker connection parameters as dict in settings
- 2.2.x
2.2.5 - Fix: add pytz requirements
2.2.4 - Fix loading module with consumers
2.2.3 - Fix consumer: down on db connection error
- 2.1.x
2.1.7 - Add put and patch api helper methods
2.1.5 - Fix: add pytz requirements
2.1.4 - Allow set rest api auth credentials and url in settings
2.1.3 - Fix loading module with consumers
2.1.2 - Fix consumer: down on db connection error
2.1.1 - Fix api error handling
2.1.0 - Any fix in consuming