Notification Server

Introduction

The notification server is a pub/sub service for the OT2.

Development Environment

• pipenv is the package manager.
• make setup will setup the project.
• make setup-ot2 will setup the project as it is on the OT2.
• make test will run the unit tests.
• make lint will run type checking and linting.
• make dev will run the server application locally in dev mode.

Project

notify_server is the root package and contains the following subpackages.

server

The server package contains the server application.

clients

The clients package has two client implementations: a subscriber and a publisher.

Asyncio Publisher Client Example

from datetime import datetime
from notify_server.models.event import Event
from notify_server.models.payload_type import UserData
from notify_server.clients.publisher import create

async def run():
    # Create the async publisher client
    pub = create("ipc:///tmp/notify-server")

    # Create a data event
    my_event = Event(
        createdOn=datetime.now(),
        publisher="my_publisher",
        data=UserData(data={
            "whatever_i_want": True
        })
    )

    # Publish an event
    await pub.send(topic="topic", event=my_event)

Publisher Client Example

from datetime import datetime
from notify_server.models.event import Event
from notify_server.models.payload_type import UserData
from notify_server.clients.publisher import create

def run():
    # Create the async publisher client
    pub = create("ipc:///tmp/notify-server")

    # Create a data event
    my_event = Event(
        createdOn=datetime.now(),
        publisher="my_publisher",
        data=UserData(data={
            "whatever_i_want": True
        })
    )

    # Publish an event
    pub.send_nowait(topic="topic", event=my_event)

Subscriber Client Example

from notify_server.clients.subscriber import create

async def run():
   # Create the async subscriber client.
   subscriber = create("tcp://localhost:5555",
                       ["topic"])

   # Use the async iterator interface to wait for events.
   async for e in subscriber:
       print(f"{e.event.createdOn}: topic={e.topic}, "
             f"publisher={e.event.publisher}, data={e.event.data}")

Subscriber Application

The notify_server.app_sub script is a useful application. It prints events from any number of topics to stdout.

To start from the command line:

python -m notify_server.app_sub -s tcp://localhost:5555 topic1 topic2

models

The models package defines event models.