Errors during execution: Call to a member function ... on null

[cruvolo]

Hello, I'm investigating using relay with Object Cache Pro on Wordpress. This would likely be a paid license in prod. OCP is working without relay, but when I add relay I get errors. I'm now running in a test environment. I get the following error on every request in the apache log: objectcache.error: Call to a member function maxMemory() on null

Based on the php code, this makes it looks like the client object is null.

Occasionally, I also get the following:

[22-Apr-2025 15:04:16 UTC] PHP Fatal error:  Uncaught Error: Call to a member function idleTime() on null in /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Connections/RelayConnection.php:228
Stack trace:
#0 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Diagnostics/Diagnostics.php(793): RedisCachePro\Connections\RelayConnection->memoize('ping')
#1 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Diagnostics/Diagnostics.php(816): RedisCachePro\Diagnostics\Diagnostics->ping()
#2 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Diagnostics/Diagnostics.php(175): RedisCachePro\Diagnostics\Diagnostics->status()
#3 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Diagnostics/Diagnostics.php(156): RedisCachePro\Diagnostics\Diagnostics->gatherGeneral()
#4 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Plugin.php(166): RedisCachePro\Diagnostics\Diagnostics->__construct(Object(RedisCachePro\ObjectCaches\RelayObjectCache))
#5 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Plugin/Licensing.php(411): RedisCachePro\Plugin->diagnostics()
#6 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Plugin/Licensing.php(297): RedisCachePro\Plugin->telemetry()
#7 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Plugin/Licensing.php(204): RedisCachePro\Plugin->request('license')
#8 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Plugin/Licensing.php(185): RedisCachePro\Plugin->fetchLicense()
#9 /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Plugin/Lifecycle.php(52): RedisCachePro\Plugin->license()
#10 /usr/src/wordpress/wp-includes/class-wp-hook.php(324): RedisCachePro\Plugin->run('')
#11 /usr/src/wordpress/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array)
#12 /usr/src/wordpress/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#13 /usr/src/wordpress/wp-settings.php(704): do_action('init')
#14 /usr/src/wordpress/wp-config-docker.php(139): require_once('/usr/src/wordpr...')
#15 /usr/src/wordpress/wp-load.php(50): require_once('/usr/src/wordpr...')
#16 /usr/src/wordpress/wp-admin/admin-ajax.php(22): require_once('/usr/src/wordpr...')
#17 {main}
  thrown in /usr/src/wordpress/wp-content/plugins/object-cache-pro/src/Connections/RelayConnection.php on line 228
[22-Apr-2025 15:04:16 UTC] objectcache.error: Call to a member function maxMemory() on null

relay.ini:

extension = relay.so
relay.environment = staging
relay.maxmemory = 128M
relay.eviction_policy = lru
relay.logfile = /tmp/relay.log
relay.loglevel = debug

Object cache pro config:

              define( 'WP_REDIS_HOST', 'redis-stg-v1.pjymjr.0001.use2.cache.amazonaws.com' );
              define( 'WP_REDIS_PORT', 6379 );
              define( 'WP_REDIS_PREFIX', 'fpmu-stg_');
              define( 'WP_REDIS_DATABASE', 2 );
              define( 'WP_REDIS_TIMEOUT', 1 );
              define( 'WP_REDIS_READ_TIMEOUT', 1 );
              define( 'WP_REDIS_MAXTTL', 86400 * 7 ); // 7 days
              define( 'WP_REDIS_CLIENT', 'relay' );
              define( 'WP_REDIS_IGBINARY', true );
              define( 'WP_REDIS_CONFIG', [
                'token' => 'xxxxxxxxxxxxxxxxxxxxxx',
                'servers' => [
                  'tcp://master.redis-stg-v1.xxxxxxxxxxxxxxx:6379/?role=primary',
                  'tcp://replica.redis-stg-v1.xxxxxxxxxxxxxxx:6379/?role=replica',
                ],
                'client' => 'relay',
                'relay' => [
                  'cache' => true,
                  'listeners' => false,
                  'invalidations' => true,
                ],
                'shared' => true,
                'replication_strategy' => 'distribute',
                'prefix' => 'fpmu-stg_',
                'port' => 6379,
                'database' => 2,
                'maxttl' => 60 * 60 * 24 * 7,   // 7 days
                'timeout' => 1.0,
                'read_timeout' => 1.0,
                'prefetch' => true,
                'split_alloptions' => true,
                'strict' => true,
                'debug' => false,
                'compression' => 'lz4',         // lz4 is faster; zstd is smaller
                'serializer' => 'igbinary',
                'async_flush' => true,
                'save_commands' => false,
              ]);
              define( 'WP_REDIS_DISABLED', false );

I can provide sanitized relay.log debug output as well. Please let me know if that is needed.

I suspect something in our config is problematic, but I'm having trouble tracking down what that might be. Any advice is appreciated. Thank you.

[cruvolo]

Adding: version numbers:

• php-config --version = 8.2.28
• "rhubarbgroup/object-cache-pro":"1.23.1"
• RELAY_VERSION="v0.10.1"
• RELAY_ARCH="x86-64"
• msgpack-3.0.0
• igbinary 3.2.16
• phpredis 6.2.0
• liblz4 1.9.4-1
• libzstd 1.5.4+dfsg2-5
• libssl1.1 1.1.1w-0+deb11u2

[tillkruss]

Will be fixed in the next version 👍

[cruvolo]

Is there any mitigation or configuration change which can be done meanwhile? Thank you.

[tillkruss]

You can replace client with client() calls to make it work.

[cruvolo]

Thank you.