How to protect against Redis::TimeoutError: Connection timed out on Heroku

Question

这似乎是一个愚蠢的问题，但我认为 Whosebug 上的某个人可能对此有一些想法。什么鬼，对吧？

我正在使用带有 1X Dynos 的 Heroku worker 来运行 Resque。有时我会收到此错误：Redis::TimeoutError: Connection timed out。它发生在 redis gem;这是堆栈跟踪：

Redis::TimeoutError Connection timed out
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/connection/ruby.rb:55 rescue in _read_from_socket
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/connection/ruby.rb:48 _read_from_socket
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/connection/ruby.rb:41 gets
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/connection/ruby.rb:273 read
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:245 block in read
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:233 io
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:244 read
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:175 block in call_pipelined
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:214 block (2 levels) in process
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:340 ensure_connected
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:204 block in process
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:286 logging
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:203 process
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:174 call_pipelined
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:146 block in call_pipeline
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:273 with_reconnect
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis/client.rb:144 call_pipeline
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis.rb:2101 block in pipelined
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis.rb:37 block in synchronize
    vendor/ruby-2.1.5/lib/ruby/2.1.0/monitor.rb:211 mon_synchronize
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis.rb:37 synchronize
    vendor/bundle/ruby/2.1.0/gems/redis-3.2.0/lib/redis.rb:2097 pipelined
    vendor/bundle/ruby/2.1.0/gems/redis-namespace-1.5.1/lib/redis/namespace.rb:413 namespaced_block
    vendor/bundle/ruby/2.1.0/gems/redis-namespace-1.5.1/lib/redis/namespace.rb:265 pipelined
    vendor/bundle/ruby/2.1.0/gems/resque-1.25.2/lib/resque.rb:214 push
    vendor/bundle/ruby/2.1.0/gems/resque-1.25.2/lib/resque/job.rb:153 create
    vendor/bundle/ruby/2.1.0/gems/resque_solo-0.1.0/lib/resque_ext/job.rb:7 create_solo
    vendor/bundle/ruby/2.1.0/gems/resque-1.25.2/lib/resque.rb:317 enqueue_to
    vendor/bundle/ruby/2.1.0/gems/resque-1.25.2/lib/resque.rb:298 enqueue

我们已经设置了 resque-retry，但我想即使 enqueue 调用甚至无法连接到 redis 也没有关系。

我目前的解决方案是用 begin/rescue 包装每个 Resque.enqueue 调用，以便我们可以重试 enqueue 调用（根据 https://github.com/resque/resque/issues/840）。但是有没有更好的办法呢？

Answer 1

Heroku Redis 允许您更改实例超时和最大内存策略设置。这些设置将在升级和 HA 故障转移期间保留。

来自documentation：

The timeout setting sets the number of seconds Redis waits before killing idle connections. A value of zero means that connections will not be closed. The default value is 300 seconds (5 minutes). You can change this value using the CLI:
$ heroku redis:timeout maturing-deeply-2628 --seconds 60
Timeout for maturing-deeply-2628 (REDIS_URL) set to 60 seconds. Connections to the redis instance will be stopped after idling for 60 seconds.

看起来在 resque 的情况下，0（不使用连接超时）将是最好的选择 (--seconds 0)。

How to protect against Redis::TimeoutError: Connection timed out on Heroku

How to protect against Redis::TimeoutError: Connection timed out on Heroku

ruby-on-rails

heroku

redis

resque

resque-retry