Async to Sync

We often use legacy services that are designed to return result in callback urls and works in async styles. May be we only doing a query to fetch some results but that thing (response) is replied in a callback url we exposed.

So I am trying here to make that thing synchronous, like a user can call /async endpoint to get the result directly rather opening a callback url. The Go server will handle those callback things. This code is a good example of how we can leverage Go's channel to do awesome things!

Here I am guessing the async server (Python) will expect a trackId with the request, so I created a trackId in the Go server and send it to the async server. It can work in the vice-versa way. May be this type of ID can be generated by the async server and pass it with the acknowledgement.

P.S. : If we want to scale this Go server, we cannot do so. Can you guess why? Go channel cannot communicate between several servers right? So we can use a simple pub-sub there to do the same thing, may be a Redis pub-sub, or RabbitMQ. I will make a new repo about that soon.

Start async server

This server is written in python. It's in the async-server-python folder. You can create a venv if you wish with python 3.7(+)

# Make virtual env 
cd async-server-python
python3 -m venv venv
source venv/bin/activate

# Install the requirements 
pip install -r requirements.txt

# Start the server 
OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES python server.py

This OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES has a broad history, here is the explanation.

Start the Go server

This server will do all the works to make that async request to sync. Install the dependencies (I used Dep as dependency manager) -

dep ensure
# Start the server 
go run main.go

Test it

Endpoint - localhost:8005/async