Wordpress Preview: addons/wp-redis-object-cache-setup.sh Wordpress Redis Object Cache Plugin Installer

Working on a new Centmin Mod 123.09beta01 addon this can install and configure Redis Object Cache Wordpress plugin as well as uninstall/remove it from Centmin Mod generated Nginx vhost based Wordpress sites. The addon will be at addons/wp-redis-object-cache-setup.sh eventually once I make the addon publicly available

The addon won't install Redis server itself, but check if Redis server is installed and running before proceeding. If Redis server isn't detected as running, then the addon will abort and exit the process.

What is Redis Object Cache Wordpress plugin?

Wordpress object caching basically caches the MySQL query results for subsequent MySQL query cache read offloading. This reduces MySQL read based query load on the MySQL server.

Official Redis Object Cache WP plugin description.

Usage

Example usage shows only 2 command options for enable and disable where they take several arguments.

Code (Text):

./wp-redis-object-cache-setup.sh
Usage:

./wp-redis-object-cache-setup.sh enable domain.com redis_db_number timeout maxttl 127.0.0.1:6379
./wp-redis-object-cache-setup.sh enable domain.com 2 2 3600 127.0.0.1:6379

./wp-redis-object-cache-setup.sh disable domain.com

Install & Enable Redis Object Cache WP Plugin

For example to install, activate and configure Redis object caching for Wordpress site on cache-enabler.domain.com with redis database number = 2 with Redis timeouts set to 2 seconds and Redis cache TTL set at 3600 seconds (1hr) using TCP port 6379 listening Redis server on 127.0.0.1.

Code (Text):

cd /usr/local/src/centminmod/addons
./wp-redis-object-cache-setup.sh enable cache-enabler.domain.com 2 2 3600 127.0.0.1:6379

example output

Code (Text):

cd /usr/local/src/centminmod/addons
./wp-redis-object-cache-setup.sh enable cache-enabler.domain.com 2 2 3600 127.0.0.1:6379
Configuring redis object cache plugin wp-login.php settings for:
/home/nginx/domains/cache-enabler.domain.com/public
Installing Redis Object Cache (2.0.13)
Downloading installation package from https://downloads.wordpress.org/plugin/redis-cache.2.0.13.zip...
Using cached file '/root/.wp-cli/cache/plugin/redis-cache-2.0.13.zip'...
Unpacking the package...
Installing the plugin...
Plugin installed successfully.
Activating 'redis-cache'...
Plugin 'redis-cache' activated.
Success: Installed 1 of 1 plugins.
Success: Added the constant 'WP_REDIS_HOST' to the 'wp-config.php' file with the value '127.0.0.1'.
Success: Added the constant 'WP_REDIS_PORT' to the 'wp-config.php' file with the raw value '6379'.
Success: Added the constant 'WP_REDIS_DATABASE' to the 'wp-config.php' file with the raw value '2'.
Success: Added the constant 'WP_REDIS_TIMEOUT' to the 'wp-config.php' file with the raw value '2'.
Success: Added the constant 'WP_REDIS_READ_TIMEOUT' to the 'wp-config.php' file with the raw value '2'.
Success: Added the constant 'WP_REDIS_MAXTTL' to the 'wp-config.php' file with the raw value '3600'.
Success: Updated object cache drop-in and enabled Redis object cache.
Restarting nginx (via systemctl):  [  OK  ]
Restarting php-fpm (via systemctl) [  OK  ]

Configured wp-login.php settings:

define( 'WP_REDIS_HOST', '127.0.0.1' );
define( 'WP_REDIS_PORT', 6379 );
define( 'WP_REDIS_DATABASE', 2 );
define( 'WP_REDIS_TIMEOUT', 2 );
define( 'WP_REDIS_READ_TIMEOUT', 2 );
define( 'WP_REDIS_MAXTTL', 3600 );

Installed & activated redis object cache plugin for:
/home/nginx/domains/cache-enabler.domain.com/public

So wp-config.php now have the following Redis object cache plugin settings added for

Code (Text):

define( 'WP_REDIS_HOST', '127.0.0.1' );
define( 'WP_REDIS_PORT', 6379 );
define( 'WP_REDIS_DATABASE', 2 );
define( 'WP_REDIS_TIMEOUT', 2 );
define( 'WP_REDIS_READ_TIMEOUT', 2 );
define( 'WP_REDIS_MAXTTL', 3600 );

Disable & Uninstall Redis Object Cache WP Plugin

To disable and remove only need to use disable option and pass the domain name of the Centmin Mod Nginx vhost Wordpress site i.e. cache-enabler.domain.com

Code (Text):

cd /usr/local/src/centminmod/addons
./wp-redis-object-cache-setup.sh disable cache-enabler.domain.com

Code (Text):

cd /usr/local/src/centminmod/addons
./wp-redis-object-cache-setup.sh disable cache-enabler.domain.com
Remove redis object cache plugin from Wordpress installation at:
/home/nginx/domains/cache-enabler.domain.com/public
Success: Deleted the constant 'WP_REDIS_HOST' from the 'wp-config.php' file.
Success: Deleted the constant 'WP_REDIS_PORT' from the 'wp-config.php' file.
Success: Deleted the constant 'WP_REDIS_DATABASE' from the 'wp-config.php' file.
Success: Deleted the constant 'WP_REDIS_TIMEOUT' from the 'wp-config.php' file.
Success: Deleted the constant 'WP_REDIS_READ_TIMEOUT' from the 'wp-config.php' file.
Success: Deleted the constant 'WP_REDIS_MAXTTL' from the 'wp-config.php' file.
Success: Object cache disabled.
Plugin 'redis-cache' deactivated.
Success: Deactivated 1 of 1 plugins.
Uninstalled and deleted 'redis-cache' plugin.
Success: Uninstalled 1 of 1 plugins.
Restarting nginx (via systemctl):  [  OK  ]
Restarting php-fpm (via systemctl) [  OK  ]

Disabled & Uninstalled redis object cache plugin for:
/home/nginx/domains/cache-enabler.domain.com/public

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That is the eventual goal after the preview setup script testing is completed - which isn't right now.

 

Pretty close though haven't decided some things yet as out of the box Redis server is only pre-configured with databases 0 to 14 for 15 databases. So if you are using one Redis database per Wordpress site, if you have a lot of Wordpress sites, you'll need more that the pre-configured amount.

For most folks right now it's pretty easy to just manually install the Redis Object cache plugin and pluck in the following in wp-config.php for

Code (Text):

define( 'WP_REDIS_HOST', '127.0.0.1' );
define( 'WP_REDIS_PORT', 6379 );
define( 'WP_REDIS_DATABASE', 2 );
define( 'WP_REDIS_TIMEOUT', 2 );
define( 'WP_REDIS_READ_TIMEOUT', 2 );
define( 'WP_REDIS_MAXTTL', 3600 );

and that's it really!

The tool is more if you're automating Wordpress installs and need to automate Redis Object cache plugin install + configuration.

 

Yup same plugin and adding those settings to wp-config is correct provided your redis server is installed and running. This addon just automates that manual process

 

You can optionally use a different redis database number for each - by default there's redis database numbers 0-15 for 16 databases as defined in /etc/redis/redis.conf config file

You can edit that number of databases in /etc/redis/redis.conf and restart redis server

Code (Text):

grep -B2 -i '^databases ' /etc/redis/redis.conf 
# a different one on a per-connection basis using SELECT <dbid> where
# dbid is a number between 0 and 'databases'-1
databases 16

Code (Text):

define( 'WP_REDIS_DATABASE', 2 );

So if you purge/flush the redis database, you only are purging data to that Wordpress instance

flush redis database 2

Code (Text):

redis-cli -n 2 flushall
OK

 

Yes I do it so you can flush entire redis database just for that Wordpress instance.

 

Yes it should

 

The above addon was never released, but you can just manually install WP redis object cache plugin and add settings as per https://community.centminmod.com/th...ject-cache-plugin-installer.20418/#post-93759

 

Yup for Redis Unix sockets is faster though Centmin Mod defaults to TCP as most Web apps and users expect such. So leave reconfiguration of Redis to use Unix sockets up to end user. Also Unix sockets only allow connections inside the server and not remote so if you have Redis cluster or load balanced setups, you'd need TCP instead