Redis Timeout Configuration in SpinupWP Drop-In

[nilsringersma]

Hi SpinupWP team,

Lately we've been encountering several fatal errors across multiple servers/sites using Redis caching. The problem is when the SpinupWP plug-in tries to purge the Redis caches, the following error appears:

Error establishing a Redis connection. socket error on read socket.

This isn’t a Redis connection issue per se — Redis itself only logs a slow script:

757:M 27 Mar 2025 15:37:34.665 # Slow script detected: still in execution after 5137 milliseconds. You can try killing the script using the SCRIPT KILL command. Script name is: d41069bcd2020f6c3be92bfd8627cc8b743778ac.

This error comes from phpredis, which is used in the object-cache.php drop-in placed by SpinupWP. The connection timeout is defined in the build_parameters() method :

'timeout' => 5,
'read_timeout' => 5,

Unfortunately, there's currently no way to override these values. We’d like to increase the timeouts since certain cache flushes can legitimately take longer than 5 seconds.

Feature Request
Could you consider one of the following approaches?

Allow overriding these values via WP_REDIS_TIMEOUT and WP_REDIS_READ_TIMEOUT constants (similar to WP_REDIS_DISABLED).
Or, if feasible within the drop-in context, introduce WordPress filters for more granular control.
This would give us a clean way to adapt Redis behavior to real-world workloads, especially on high-traffic or WooCommerce-heavy sites.

Another option would be to set the timeout and read_timeout to the default 0, so we can leverage the default_socket_timeout as SpinupWP allows us to override the fpm's ini on a per-site level.

Thanks in advance — happy to help test or PR this if helpful!

P.S.: It has also been increased from 1 to 5 in the past (#70), but it seems to me that the value of 5 is still too low for larger sites.

[nilsringersma]

For the time being I've setup Ansible on our Spinup platform to configure both redis-server with a lua-time-limit and busy-reply-threshold that suits us better. Additionally I also created a playbook that searches all object-cache.php drop-in modules created by SpinupWP and updates the timeouts set to 5 to a timeout that suits us better. All problems on all servers and sites have been resolved now.

Off-topic:
During this process, I did notice that there were still drop-ins with the timeout set to 1, this has been updated a while ago in #70. Does this mean that when you guys update the drop-in, the drop-in itself on sites already using the SpinupWP plug-in will not update? I'm sure I saw code somewhere in this plug-in that's responsible for updating the drop-in, but perhaps that's not working. If needed I can investigate that further and make a separate issue if true.

[georgefehr]

Just a heads up, the drop-in already supports the WP_REDIS_TIMEOUT and WP_REDIS_READ_TIMEOUT constants.

[nilsringersma]

Just a heads up, the drop-in already supports the WP_REDIS_TIMEOUT and WP_REDIS_READ_TIMEOUT constants.

We do not find any of these constants in either the Spinupwp plug-in, or the drop-in created for the object caches. Can you elaborate further on where you find these constants?

Earlier we have updated the drop-in created by Spinupwp ourselves solving all these issues on all our websites. Lately Spinupwp have updated the drop-in module, overwriting our changes and re-introducing this issue on all our websites.

This issue is extremely annoying since we strongly believe those timeout values are subject to change depending on the platform and the applications hosted. Earlier Spinupwp has updated the timeout ( #70 ) from 1 to 5, but 5 is too short for our use cases.

Right now we have to run Ansible over all sites on all servers to increase the timeouts and fix this problem, but this is only a hotfix as Spinupwp will overwrite the object-cache.php drop-in occasionally.

[georgefehr]

We do not find any of these constants in either the Spinupwp plug-in, or the drop-in created for the object caches. Can you elaborate further on where you find these constants?

All of the parameters in the build_parameters() function in the drop-in can be overwritten using a constant. Here's a link to the relevant line in the code, where it loops over the available settings to check for constants:

spinupwp-plugin/drop-ins/object-cache.php

Line 661 in b20d6b7

$constant = sprintf( 'WP_REDIS_%s', strtoupper( $setting ) );

Note that the drop-in is a modified copy of the Redis Object Cache plugin, and most of the configuration options listed here are supported.