How to log error message in drupal

Question

How to log our own error messages(for ex: error due to invalid user date entry) which is generated in php program to drupal error log.

Answer 1

Both watchdog for D7 & \Drupal::logger for D8 will write log in watchdog table (in your database), and with HUGE data logged, you can imagine performance impact.

You can use error_log php function to do it (see PHP manual).

error_log("Your message", 3, "/path/to/your/log/file.log");

You need to have permission to write in your log file (/path/to/your/log/file.log)

drupal-8drupalphplog

Answer 2

1) Indeed, watchdog is a standard way to record own PHP errors.

2) Alternatively, if you need to immediately see error messages while debugging your Drupal pages, you may want to see them logged/printed right at the related page - in FireBug console. Sometimes is this very convenient when you can see page-related just-in-time logs. This requires - Devel module, Firebug extension to FireFox and possibly Firephp.

You can use the dfb() function to write log messages directly to the general Firebug console.

dfb($input, $label = NULL)

If you want to keep your Drupal-related log messages out of the normal Firebug console, you can write messages to the Drupal for Firebug log with the firep() function:

firep($item, $optional_title)

Answer 3

Drupal 8

// Logs a notice
\Drupal::logger('my_module')->notice($message);
// Logs an error
\Drupal::logger('my_module')->error($message);

See more examples at How to Log Messages in Drupal 8.

Answer 4

In drupal 7 we can log message by following method:

drupal watchdog function we can use to log message in database , make sure we have enabled optional core module for Database Logging at /admin/build/modules.

watchdog($type, $message, $variables = array(), $severity = WATCHDOG_NOTICE, $link = NULL)

$type: The category to which this message belongs , Example: PHP,cron.., we can filter message by type.

$message : The message to store in the log,Example: 'The following module is missing from the file system: security_review'

$variables : Array of variables to replace in the message on display or NULL if message is already translated or not possible to translate. to make message translated , do not pass dynamic value pass variables in the message should be added by using placeholder strings.

Example: watchdog('cg_volunteer', 'cg in form_alter %formly', array('%formly' => $form['#id']), WATCHDOG_NOTICE, $link = NULL);

$severity The severity of the message,logs can be filter by severity as per RFC 3164. Possible values are WATCHDOG_ERROR, WATCHDOG_WARNING, etc. For more example see https://api.drupal.org/api/drupal/includes!bootstrap.inc/function/watchdog/7.x

$link: A link to associate with the message.

Example

// for logs notices

watchdog('my_module', $message, array());

// for Loging Error

watchdog('my_module', $message, array(), WATCHDOG_ERROR);

In drupal 8 we used following method:

// For Logs a notice.

\Drupal::logger('my_module')->notice($message);

// For Logs an error.

\Drupal::logger('my_module')->error($message);

// For Alert, action must be taken immediately.

\Drupal::logger('my_module')->alert($message);

// For Critical message.

\Drupal::logger('my_module')->critical($message);

// For Debug-level messages.

\Drupal::logger('my_module')->debug($message);

//For Emergency, system is unusable.

\Drupal::logger('my_module')->emergency($message);

//For Warning

\Drupal::logger('my_module')->warning($message);

//For Informational messages.

\Drupal::logger('my_module')->info($message);

Also for translate we should not use t() function.

\Drupal::logger('my_module')->alert('Message from @module: @message.', [
'@module' => $module,
'@message' => $message,
]);

this will be translated on run time.

Example :

\Drupal::logger('content_entity_example')->notice('@type: deleted %title.',
array(
'@type' => $this->entity->bundle(),
'%title' => $this->entity->label(),
));

Answer 5

Watchdog is the way to go for a production system no doubt but during debugging I find the drupal_set_message function useful.

It outputs the message to the screen where the 'Operation Successful'-type messages are normally displayed (so make sure you remove them before making the site Live).

http://api.drupal.org/api/function/drupal_set_message/6

Answer 6

// Get logger factory.
$logger = \Drupal::service('logger.factory');

// Log a message with dynamic variables.
$nodeType = 'Article';
$userName = 'Admin';
$logger->get($moduleName)->notice('A new "@nodeType" created by %userName.', [
    '@nodeType' => $nodeType,
    '%userName' => $userName,
]);

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