How does dyno know about redis is unavailable?

[lampmanyao]

Hi, here is my test case, and i use hiredis client:
0) dyno client reads a key

1. dynomite replies "ERR Storage: Connection refused" if it's redis was unavailable

Because hiredis can read something from dynomite, so redisContext's err field would not be set to ERROR, and the redisReply is not NULL. We get the wrong value.

My question is:
How does dyno handle this situation?

[lampmanyao]

We won't get the wrong value.
Because redisReply has a type field, in this situation, it will be set to REDIS_REPLY_ERROR.