Debugging the Resource Type Implementation

The DSDL has built-in features to help you debug your data service.

The DSDL utility scds_syslog_debug() provides a basic framework for adding debugging statements to the resource type implementation. The debugging level (a number between 1-9) can be dynamically set for each resource type implementation on each cluster node. A file named /var/cluster/rgm/rt/rtname/loglevel, which contains only an integer between 1 and 9, is read by all resource type callback methods. The DSDL function scds_initialize() reads this file and sets the debug level internally to the specified level. The default debug level 0 specifies that the data service is not to log debugging messages.

The scds_syslog_debug() function uses the facility that is returned by the scha_cluster_getlogfacility() function at a priority of LOG_DEBUG. You can configure these debug messages in the /etc/syslog.conf file.

You can turn some debugging messages into information messages for regular operation of the resource type (perhaps at LOG_INFO priority) by using the scds_syslog() function. Note that the sample DSDL application in Chapter 8, Sample DSDL Resource Type Implementation includes calls to the scds_syslog_debug() and scds_syslog() functions.