[Browser] Sending more than 6 simultaneously requests to yagna is blocked by the Chrome-based browsers

[grisha87]

Context

golem-js can be run in WebBrowsers. To deliver functionality, the page using golem-js is making requests to the yagna running on localhost.

Problem

Unfortunately, we run into the limitation of max 6 requests that can be sent at the same time to the same domain - specifically http://localhost:7465/ . For reference, check out this article.

Each browser has a different default value for the maximum parallel connections. For example, in Google Chrome, the default value is 6 connections per domain. This means that Chrome will only make a maximum of 6 HTTP requests to a single domain at the same time.

Why are having the problem?

golem-js polls information from different event endpoints exposed by yagna. At least 3 requests are on-line at the same time:

• demand subscription + proposal events
• invoice evens
• debit note events
• agreeement events

This leaves out only 3 requests of free capacity to schedule exe-script requests or fetch exe-script results. If we're actively waiting for events by doing polling or even waiting for Server Sent Events, we're running into that limitation which makes the golem-based application unusable.

What should we change in the platform?

Solution proposal 1

Ideally, yagna woud deliver a single event endpoint that can emit various types of events (Server Sent Events + Event Source with different event types). This would allow us to keep only 1 connection for all kinds of events opened all the time, feeing the rest of the limit for other operations.

To really benefit from that, all kinds of events, even exec-batch-results would have to be delivered.

That is, ofcourse, relevant only in the context of running golem-related things in the browser. If golem-js won't be the beneficiary here, the requestor/provider dashboard will be as these web-apps would be subject of the same limitations as our demo apps.

Solution proposal 2

It seems that switching to HTTP/2 might do the trick for us.

Solution proposal 3 (by reqc)

Implement STOMP server in yagna and communicate using it. We can break this to 2 phases:

1. Initiate an operation via REST API and receive results via STOMP queue/topic
2. Full STOPMP - we initate opration via STOMP call (RPC) and receive the response