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

Hi,

You can use the watchdog function :

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

Quoting the manual, the parameters are :

• $type The category to which this message belongs.
• $message The message to store in the log.
• $variables Array of variables to replace in the message on display or NULL if message is already translated or not possible to translate.
• $severity The severity of the message, as per RFC 3164
• $link A link to associate with the message.

And the error levels can be found on the page of watchdog_severity_levels. For an error, you'll most probably use WATCHDOG_ERROR, or maybe even something more "critical", depending on the kind of error.

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

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%5Fset%5Fmessage/6