OpenSSL::SSL::SSLError: SSL_write at Heroku

[kokuyouwind]

At heroku, minimum app raises OpenSSL::SSL::SSLError: SSL_write .

# frozen_string_literal: true

ruby "2.7.4"
source "https://rubygems.org"

git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }

# gem "rails"

gem 'ruboty-slack_rtm'
gem 'ruboty-redis'

Log

Dec 06 16:34:11 ruboty-lp app/bot.1 E, [2021-12-07T09:34:11.071481 #4] ERROR -- : OpenSSL::SSL::SSLError: SSL_write
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/ruby-2.7.4/lib/ruby/2.7.0/openssl/buffering.rb:322:in `syswrite'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/ruby-2.7.4/lib/ruby/2.7.0/openssl/buffering.rb:322:in `do_write'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/ruby-2.7.4/lib/ruby/2.7.0/openssl/buffering.rb:339:in `block in write'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/ruby-2.7.4/lib/ruby/2.7.0/openssl/buffering.rb:338:in `each'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/ruby-2.7.4/lib/ruby/2.7.0/openssl/buffering.rb:338:in `inject'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/ruby-2.7.4/lib/ruby/2.7.0/openssl/buffering.rb:338:in `write'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/bundle/ruby/2.7.0/gems/websocket-client-simple-0.3.0/lib/websocket-client-simple/client.rb:75:in `send'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/bundle/ruby/2.7.0/bundler/gems/ruboty-slack_rtm-8d81111cdd1f/lib/ruboty/slack_rtm/client.rb:72:in `block (2 levels) in keep_connection'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/bundle/ruby/2.7.0/bundler/gems/ruboty-slack_rtm-8d81111cdd1f/lib/ruboty/slack_rtm/client.rb:69:in `loop'
Dec 06 16:34:11 ruboty-lp app/bot.1 /app/vendor/bundle/ruby/2.7.0/bundler/gems/ruboty-slack_rtm-8d81111cdd1f/lib/ruboty/slack_rtm/client.rb:69:in `block in keep_connection'
Dec 06 16:34:11 ruboty-lp app/bot.1 connection closed.
Dec 06 16:34:13 ruboty-lp app/bot.1 activated.

I think these updates are related.

https://api.slack.com/changelog

November 2021
If you still use rtm.connect or rtm.start to connect to Slack, you'll notice that all WebSocket URLs now begin with wss://wss-primary.slack.com.
As previously announced, apps & integrations created after today, November 30, 2021, must use rtm.connect instead of the deprecated rtm.start when connecting to the RTM API. Learn more about this and what's next for existing users of rtm.start.

[ry023]

I met same problem and realized that the cause was probably shokai/websocket-client-simple.

I monkey patched this line as follows and it worked fine in my application.

@socket.hostname = uri.host
@socket.connect

hostname= method is used for SNI extensions. I expect that slack has probably changed their architectures and use SNI ...

[takaishi]

I met same problem too.
I tried to use slack-ruby-client instead of websocket-client-simple and slack-api, it looks like work well.

[linyows]

There was already a pull-request for SNI support here: shokai/websocket-client-simple#36

[unasuke]

@kokuyouwind @ry023 @takaishi @linyows
Hello!!! SNI-supported websocket-client-simple was released!!! Could you try it?

• https://rubygems.org/gems/websocket-client-simple/versions/0.5.0
• https://github.com/ruby-jp/websocket-client-simple

[linyows]

Many thanks!