When redis-server is down, NotImplementedError is raised

[jeremyjung]

When redis-server goes down and a command is sent or client was waiting for a blocking pop, a NotImplementedError is raised.

Example stack trace:

        6: from /home/name/.gem/ruby/2.6.1/gems/async-1.15.2/lib/async/task.rb:199:in `block in make_fiber'
        5: from queue.rb:10:in `block in <main>'
        4: from /home/name/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/methods/keys.rb:37:in `exists'
        3: from /home/name/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/client.rb:104:in `call'
        2: from /home/name/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/pool.rb:51:in `acquire'
        1: from /home/name/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/client.rb:107:in `block in call'
/home/name/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/protocol/resp.rb:119:in `read_object': Implementation for token  missing (NotImplementedError)

Sample program to reproduce:

Async do
  client = Async::Redis::Client.new(Async::Redis.local_endpoint)
  _, command = client.blpop(10, "test")
end.wait

1. Open redis-server
2. Run sample application
3. Close redis-server during blpop.

Ideally an error related to connection should be raised. For instance, a library specific CannotConnectError (Used in redis-rb gem) or lower level ECONNREFUSED

[ioquatix]

This should be something like EOFError if it occurs during middle of reading response.

[ioquatix]

This is where it should be failing I guess.

async-redis/lib/async/redis/protocol/resp.rb

Line 71 in 301852c

line = read_line

Let me take a closer look.

[ioquatix]

I think this is already fixed on master branch but there was one other case where it was possible so I also fixed that. Can you try master?

[ioquatix]

Sorry, I didn't push master on my other computer.... I did it just now.

[jeremyjung]

I switched the Gemfile to use master

Using async 1.15.4 from https://github.com/socketry/async (at master@d07dc4a)
Using async-io 1.19.0 from https://github.com/socketry/async-io (at master@4dfd149)
Using async-redis 0.3.3 from https://github.com/socketry/async-redis (at master@b0cd6db)

I still get the NotImplementedError when testing a get command while server is down and having the server disconnect while inside a blpop call.

[jeremyjung]

Actually my bad, it does raise a Async::Redis::ServerError. I think things are working.

[jeremyjung]

Sorry again, haha.. it does still have the NotImplementedError. The ServerError was a different issue. So I still see the same problem on master.

[ioquatix]

Can you give me stack trace from master

[jeremyjung]

Traceback (most recent call last):
	6: from /Users/jjung/.gem/ruby/2.6.1/gems/async-1.15.4/lib/async/task.rb:199:in `block in make_fiber'
	5: from redis.rb:7:in `block in <main>'
	4: from /Users/jjung/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/methods/lists.rb:27:in `blpop'
	3: from /Users/jjung/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/client.rb:104:in `call'
	2: from /Users/jjung/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/pool.rb:51:in `acquire'
	1: from /Users/jjung/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/client.rb:107:in `block in call'
/Users/jjung/.gem/ruby/2.6.1/gems/async-redis-0.3.3/lib/async/redis/protocol/resp.rb:119:in `read_object': Implementation for token  missing (NotImplementedError)

[jeremyjung]

My apologies again. If I clone the async-redis repository and create a sample program at base then require_relative './lib/async/redis' I get the expected error (EOFError).

I thought that having a separate project and pulling all the gems directly from master in the Gemfile would have the same result but it did not. I guess maybe I am missing something.

If you would like I can try to create a spec that disconnects the client and looks for an EOFError to return.

[ioquatix]

Sounds like a great idea

[ioquatix]

I thought that having a separate project and pulling all the gems directly from master in the Gemfile would have the same result but it did not. I guess maybe I am missing something.

Maybe try bundle update? Did it check out the latest revision from git? b0cd6dbad8dd589ed7665ce95e576471d1c7edaa