Trilogy::SSLError is raised when a vitess vtgate is shut down

[brendar]

When using trilogy >= 2.5.0 with Vitess and connected to a vtgate (the proxy that mysql clients connect to), trilogy raises trilogy_query_recv: SSL Error: (null) (Trilogy::SSLError) when the vtgate shuts down and closes the connection on the server side. This issue did not occur in Trilogy v2.4.1, which raised trilogy_query_recv: TRILOGY_CLOSED_CONNECTION (Trilogy::QueryError).

This error makes it hard for clients to know whether they should reconnect and retry the query.

e.g. with 2.6.0

irb(main):001:0> vtgate_client = Trilogy.new(host: "127.0.0.1", port: 23306, ssl: true, ssl_mode: Trilogy::SSL_REQUIRED_NOVERIFY)
=> #<Trilogy:0x00007f855c19eb30 @connection_options={:host=>"127.0.0.1", :port=>23306, :ssl=>true, :ssl_mode=>3}>

# vtgate is stopped

irb(main):002:0> vtgate_client.query("SELECT 1")
(irb):2:in `query': trilogy_query_recv: SSL Error: (null) (Trilogy::SSLError)
	from (irb):2:in `<main>'
	from /opt/rubies/ruby-3.1.4-pshopify1/lib/ruby/gems/3.1.0/gems/irb-1.4.1/exe/irb:11:in `<top (required)>'
	from /usr/local/bin/irb:25:in `load'
	from /usr/local/bin/irb:25:in `<main>'

mysql2 raises this as a Mysql2::Error::ConnectionError, e.g.

irb(main):002:0> mysql2_vtgate_client = Mysql2::Client.new(host: "127.0.0.1", port: 23306, ssl_mode: :required)
=>
#<Mysql2::Client:0x00007f275fcd7480

# vtgate is stopped

irb(main):003:0> mysql2_vtgate_client.query("SELECT 1")
/home/spin/.local/share/gem/ruby/3.1.0/gems/mysql2-0.5.5/lib/mysql2/client.rb:151:in `_query': Lost connection to MySQL server during query (Mysql2::Error::ConnectionError)
	from /home/spin/.local/share/gem/ruby/3.1.0/gems/mysql2-0.5.5/lib/mysql2/client.rb:151:in `block in query'
	from /home/spin/.local/share/gem/ruby/3.1.0/gems/mysql2-0.5.5/lib/mysql2/client.rb:150:in `handle_interrupt'
	from /home/spin/.local/share/gem/ruby/3.1.0/gems/mysql2-0.5.5/lib/mysql2/client.rb:150:in `query'
	from (irb):3:in `<main>'
	from /opt/rubies/ruby-3.1.4-pshopify1/lib/ruby/gems/3.1.0/gems/irb-1.4.1/exe/irb:11:in `<top (required)>'
	from /usr/local/bin/irb:25:in `load'
	from /usr/local/bin/irb:25:in `<main>'

Running a git bisect, it looks like this behavior was introduced in #112

If you're interested in reproducing locally, I've added an SSL-enabled vtgate to docker-compose.yml in this branch.

[jhawthorn]

Thanks for the report and especially reproduction! We may have had the desired behaviour prior to #112, but that would have been due to a bug (two wrongs making a right 😅) and may not have been consistent (it relied on us attempting to read/write on that closed connection after we'd seen an error).

I've opened #128 which should fix this.

Also worth noting is that in Trilogy 2.6.0 TRILOGY_CLOSED_CONNECTION now has a proper error class Trilogy::EOFError instead of the generic Trilogy::QueryError, hope that helps 😊!

[brendar]

I can confirm that #128 resolves the issue. Thanks for the fix!