Don't show HTTP2 GoawayError in terminal

[bruno-]

Here's a minimal example that illustrates the problem:

require "async"
require "async/http/internet"

Async do |task|
  internet = Async::HTTP::Internet.new
  puts internet.get("https://economist.com/").status # 301, HTTP2 connection
  task.sleep 10 # Protocol::HTTP2::GoawayError raised in ~5 seconds as the server closes the connection.

  puts "This code unexpectedly runs because the exception was only raised in the background."
  puts "The internet object is also fine."
  puts internet.get("https://economist.com/").status # 301
end

The problem is Protocol::HTTP2::GoawayError + its backtrace show up in the terminal whenever the remote server benevolently closes idle connection outside the request-response cycle. The premise is: this scenario is not an error. It's equivalent to HTTP1 connection close after the request is done.

The current behavior looks like a scary issue (red characters in the terminal, stack trace etc), but it's not. In fact, async-http handles things great and there's nothing a user should do (like rescue, retry or similar).

I have not run an extensive research, but I think all the sites running http2 using amazon cloudfront or Incapsula/imperva do benevolently close idle http2 connections after 4 minutes. This maybe applies to other CDNs. Heres an example for site running on Incapsula CDN:

require "async"
require "async/http/internet"

Async do |task|
  internet = Async::HTTP::Internet.new
  puts internet.get("https://www.proofpoint.com").read&.length
  task.sleep 250 # Protocol::HTTP2::GoawayError raised in 4 minutes
end

The proposal: don't show background task exception for Protocol::HTTP2::GoawayError. I will add specs and improve the code if the idea is green-lighted.

Types of Changes

• [x] Bug fix.
• [ ] New feature.
• [ ] Performance improvement.

Testing

• [ ] I added new tests for my changes.
• [x] I ran all the tests locally.

[ioquatix]

This seems fine to me and it's probably the right thing to do.

[bruno-]

Feedback addressed.

[ioquatix]

Thanks.