Some plugins may only work when certain extra conditions are met, like having an unusual PHP extension installed or needing certain write permission on the file system. In these cases it is recommended to add new checks to the Matomo diagnostics system check which you can find by going to Matomo Administration -> Diagnostic -> System Check.
Matomo typically differentiates between three kind of checks:
A new check can be useful if your plugin requires for example a certain PHP extension or other capabilities for the plugin to work. If a Matomo installation does not have the required capability, then the user will be able to find out about this problem and find help to fix this issue.
An optional check can be useful if there's a way to improve the performance of your plugin, or if there are other optional or recommended changes that improve the experience.
Adding an informational output is typically useful for the plugin developer themselves to troubleshoot issues. Such information can then be easily requested from the user when a bug report is made. The user can then provide this information by simply copy / pasting the system check.
Typical information could be version numbers of installed packages or information about stored data.
To create a new system check, use the console to execute the below command (requires Matomo 4.4.1):
./console generate:system-check
The command will ask for your plugin name and for the name of the system check you want to create. You should enter some meaningful name that describes the check well. For example, "JS Directory Write Permission Check".
Once all information is provided, a system check class will be created in the Diagnostic directory of your plugin containing an example on how to define a system check. In the above example it would have created a file Diagnostic/JsDirectoryWritePermissionCheck.php within the chosen plugin.
Matomo won't discover your newly created system check automatically. You have to tell Matomo that it exists using the config/config.php file within your plugin.
First you need to decide if your system check is of type required, optional or informational. Then you can register one or multiple checks like below:
return [
'diagnostics.required' => DI\add(array(
// adds a required system check
DI\get('Piwik\Plugins\MyPluginName\Diagnostic\JsDirectoryWritePermissionCheck'),
)),
'diagnostics.optional' => DI\add(array(
// adds an optional system check
DI\get('Piwik\Plugins\MyPluginName\Diagnostic\JsDirectoryWritePermissionCheck'),
)),
'diagnostics.informational' => DI\add(array(
// adds an informational system check
DI\get('Piwik\Plugins\MyPluginName\Diagnostic\JsDirectoryWritePermissionCheck'),
))
];
Your plugin can also provide multiple system checks of different types.
To implement the actual check you need to edit the execute method within the diagnostic class. In the case of our example where we are checking if a specific directory is writable, this could look like this:
public function execute()
{
$result = [];
$directoryToCheck = PIWIK_DOCUMENT_ROOT . '/js';
if (!is_writable($directoryToCheck)) {
$status = DiagnosticResult::STATUS_ERROR;
$comment = "The $directoryToCheck is not writable but it is required because ... To make this directory writable execute ...";
} else {
$status = DiagnosticResult::STATUS_OK;
$comment = '';
}
$label = 'JS Direcotry Writable';
$result[] = DiagnosticResult::singleResult($label, $status, $comment);
return $result;
}
Each check can have one of four different statuses:
DiagnosticResult::STATUS_OK) - Everything is fine and the system passes the check.DiagnosticResult::STATUS_ERROR) - There is an error which needs to be fixed. Typically used for a required check.DiagnosticResult::STATUS_WARNING) - There is a warning and it is optional to fix this. Typically used for an optional check.DiagnosticResult::STATUS_INFORMATIONAL) - Only provides information. Typically used for an informational check.You can check for different requirements in each diagnostic class and return multiple results by adding another result to the $result array. However, we don't recommend mixing required, optional and informational checks within one class.
Similarly, you can print informational output that helps you as a developer troubleshoot bug reports. For example, you can print the PHP version like this:
public function execute()
{
$result = [];
$label = 'PHP Version';
$comment = 'The PHP version is ' . PHP_VERSION;
$result[] = DiagnosticResult::informationalResult($label, $comment);
return $result;
}
You can remove existing system checks from other plugins using the config/config.php within your plugin where you define any system check class that should be removed like this:
return [
'diagnostics.disabled' => DI\add(array(
DI\get('Piwik\Plugins\Diagnostics\Diagnostic\PhpVersionCheck'),
)),
];
Above example would remove the PHP version check from the system report and afterwards the check will be no longer executed and neither be visible anywhere.