Question about using redigo for that it does not support concurrently Receive and Close

[tony21177]

Fleet version (Head to the "My account" page in the Fleet UI or run fleetctl version): 3.10.1

Fleet tier (Are you using the free (Fleet Core) or paid (Fleet Basic) tier?): free

User role (Which role are you assigned in Fleet? (Admin, Maintainer, or Observer)):

3 roles are introduced in Fleet 4.0.0. If you're using a prior version of Fleet or don't know your assigned role, please feel free to leave this item blank.

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🧑‍💻  Expected behavior

As Redigo's documentation describe:

Connections support one concurrent caller to the Receive method and one concurrent caller to the Send and Flush methods. No other concurrency is supported including concurrent calls to the Do method.

For full concurrent access to Redis, use the thread-safe Pool to get, use and release a connection from within a goroutine. Connections returned from a Pool have the concurrency restrictions described in the previous paragraph.

https://pkg.go.dev/github.com/garyburd/redigo/redis#hdr-Concurrency

💥  Actual behavior

https://github.com/fleetdm/fleet/blob/main/server/pubsub/redis_query_results.go#L163
redis_query_results.go#L163
the goroutine use the redis connection to Receive

https://github.com/fleetdm/fleet/blob/main/server/pubsub/redis_query_results.go#L167
redis_query_results.go#L167
but another goroutine use the same connection to Close.

Doesn't it violate the redigo not supporting concurrency limitation?

[tony21177]

Hi,
Because the connection is retrieved from the connection pool,so it assure the thread safety?
If so,I will close the issue

[tony21177]

profile001.pdf
Actually,My fleet server bumps into a redis max connections issue , and the attached file is the goroutine debug pdf
the detailed description as the other issue I report #1541

[chiiph]

Hi @tony21177, the connection retrieving from the pool is thread safe. But what I believe that means is that the retrieving is thread safe, not the usage. Which is why it says "use and release a connection from within a goroutine".

Thank you for reporting this, I'll have a PR soon.