WP Toolkit shows WordPress instance as broken when a domain is using Alt-PHP: Error establishing a database connection

Kuzma Ivanov

Updated January 08, 2024 10:32

kb: bug Plesk for Linux ext: wptk ABT: Group B

Applicable to:

Plesk for Linux

Symptoms

Plesk is installed on a CloudLinux server.
When installing WordPress via WP Toolkit, the operation fails with the following error message:

PLESK_ERROR: PHP Fatal error: Uncaught Error: Call to undefined function json_encode() in /usr/local/psa/admin/plib/modules/wp-toolkit/vendor/wp-cli/wp-cli/vendor/mustache/mustache/src/Mustache/Engine.php:637
When scanning or refreshing a WordPress instance in WP Toolkit, one of the following happens:
- the operation completes with the following error message and the instance is marked as broken:
  
  PLESK_ERROR: Your PHP installation appears to be missing the MySQL extension which is required by WordPress. PHP Fatal error: Uncaught Error: Call to undefined function json_encode() in /usr/local/psa/admin/plib/modules/wp-toolkit/vendor/wp-cli/wp-cli/php/class-wp-cli.php:742
- the instance is marked as broken and the following error message appears in /var/log/plesk/panel.log:
  
  CONFIG_TEXT: ERR [extension/wp-toolkit] Failed to reset cache for the instance #X, reason: Error establishing a database connection.

Cause

This was reported as a WP Toolkit bug with ID EXTWPTOOLK-4371 and in the scope of PPP-52061 (Plesk 18.0.36) default configuration of Alt-PHP was adjusted to comply with Plesk needs.

PHP extensions like json.so and mysqli.so for Alt-PHP are disabled.

Resolution

Apply one of the following workarounds:

Create a symbolic link for mysql socket

Connect to the Plesk server via SSH.
Create a symbolic link:

# ln -s /var/lib/mysql/mysql.sock /tmp/mysql.sock

Enable additional extensions in PHP configuration

Log in to Plesk.
Go to Domains > example.com > PHP Settings.
Add the following lines to the Additional configuration directives field:

CONFIG_TEXT: extension=json.so
extension=mysqli.so
extension=pdo_mysql.so

Note: If the error "Module 'mysqli' already loaded at Unknown#0" is shown when accessing domains, disable the above extensions at Domains > example.com > PHP Selector.

Change Alt-PHP to PHP provided by Plesk

Log in to Plesk.
Go to Domains > example.com > PHP Settings.
Change PHP handler to any non Alt-PHP.
Go to Domains > example.com > WordPress.
On the affected WordPress instance, click > Detach.
Click Scan to detect the instance.

Screenshot_2020-06-03_Plesk_Obsidian_18_0_25.png
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