Microservices using ZMQ and Go. You need docker and docker compose to run this.

Suggestions and pull requests welcome 😃

Build the images:

docker-compose build

Run the containers with:

docker-compose up

You should see something like this:

worker_1  | Received request [Hello 9]
client_1  | Received [Hello 9]
client_1  | It took: 10.074335 seconds.

It shows that it took more or less 10 seconds to process all the requests for 1 client. This example client is doing 10 requests, each request takes 1 second to process on the worker for this demo.

You can define the number of clients:

docker-compose up --scale client=2

stop:

docker-compose down

With more clients the time to process everyone increases, so we need to make it scalable, you can define the number of threads for each worker in the docker-compose.yaml file, or run any number of workers with:

docker-compose up --scale client=2 --scale worker=2

The router container will receive all the requests from the clients, his job is to do a fairly distribution of the workload.
Is based on the request-reply broker of the ZMQ guide: http://zguide.zeromq.org/page:all#Shared-Queue-DEALER-and-ROUTER-sockets

The worker connects to a router and is always waiting for requests, its has a internal router to distribute the work by his threads. If only one worker process is preferred the router can be removed making a direct communication between the clients and the worker.

The logger container work as a log sink, it pulls the logs from the workers and write to a log file.
It uses: https://github.com/natefinch/lumberjack for log rotation.
Logging options:

log.SetOutput(&lumberjack.Logger{
        Filename:   "logs/log.log",
        MaxSize:    2, // megabytes
        MaxBackups: 10,
        MaxAge:     28,   //days
        Compress:   true, // disabled by default
    })