Next iteration of pub/sub quickstarts (python, dotnet)

[paulyuk]

This addresses a few challenges with the current quickstart both around functionality and style:

Python

• example: checkout service is now the publisher, and order-processor is now the subscriber. this matches common examples, e.g. https://docs.microsoft.com/en-us/azure/architecture/example-scenario/data/ecommerce-order-processing
• function: use HTTP routes in subscriber, in case app protocol not set to gRPC. I like the decorator example but we need a bigger change for that.
• function: send a python -> json object for orders instead of raw int for orderid, which will break json.dumps parsing downstream. now it looks like order = {"orderid": random.randint(1, 1000)}
• function: reduced use of random and simplified sleep
• style:
• created a folder for each service
• changed all files to lowercase
• changed main running file name to app.py
• updated requirements.txt with matching pip install dependencies, namely dapr and Flask
• checked with Flake8 linter

Dotnet (C#)

• matches python example with checkout and order-processor
• .NET 6
• minimal coding pattern, no Main or controllers needed. See https://docs.microsoft.com/en-us/aspnet/core/fundamentals/minimal-apis?view=aspnetcore-6.0
• passed Order object as json data, not just int orderid

[greenie-msft]

PubSub Subscribe was recently added to Flask Dapr: dapr/python-sdk#351.

My suggestion is to publish this update and use it as it simplifies the amount of code developers need to write:

from flask import Flask, request
from flask_dapr import DaprApp
app = Flask('myapp')
dapr_app = DaprApp(app)

@dapr_app.subscribe(pubsub='pubsub', topic='some_topic', route='/some_endpoint')
def my_event_handler():
  # request.data contains pubsub event
  pass

[paulyuk]

PubSub Subscribe was recently added to Flask Dapr: dapr/python-sdk#351.

My suggestion is to publish this update and use it as it simplifies the amount of code developers need to write:

from flask import Flask, request
from flask_dapr import DaprApp
app = Flask('myapp')
dapr_app = DaprApp(app)

@dapr_app.subscribe(pubsub='pubsub', topic='some_topic', route='/some_endpoint')
def my_event_handler():
  # request.data contains pubsub event
  pass

Agreed. Nice! It's in. You just have to pip install the 1.5 sdk version but the requirements.txt now does this.

[amulyavarote]

We might have to change the variables and method names later on to keep it consistent across all the programming languages. I am currently working on the spec/template to be followed in the coding/design. We might make few changes according to it.

Now the PR looks good to me :-)