WebLogic Diagnostics Framework

WebLogic Diagnostic Framework (WLDF) is a monitoring and diagnostic framework that defines and implements a set of services that run within BEA WebLogic Server processes and participate in the standard server life cycle. WLDF falls somewhere between the old way of monitoring the environment (using the console or developing JMX based monitoring tools) and the fancy third-party JMX and SNMP monitoring tools.Using WLDF, you can create, collect, analyze, archive, and access diagnostic data generated by a running server and the applications deployed within its containers.WLDF includes several components for collecting and analyzing data:

• Diagnostic Image Capture: Creates a diagnostic snapshot from the server that can be used for post-failure analysis.
• Archive: Captures and persists data events, log records, and metrics from server instances and applications.
• Instrumentation: Adds diagnostic code to WebLogic Server instances and the applications running on them to execute diagnostic actions at specified locations in the code, usually at the beginning or end of a method (achieved using AspectJ) . The Instrumentation component provides the means for associating a diagnostic context with requests so they can be tracked as they flow through the system.
• Harvester: Captures metrics from run-time MBeans, including WebLogic Server MBeans and custom MBeans, which can be archived and later accessed for viewing historical data.
• Watches and Notifications: Provides the means for monitoring server and application states and sending notifications based on criteria set in the watches.
• Logging services: Manages logs for monitoring server, subsystem, and application events.

WLDF provides a set of standardized application programming interfaces (APIs) that enable dynamic access and control of diagnostic data, as well as improved monitoring that provides visibility into the server. Independent Software Vendors (ISVs) can use these APIs to develop custom monitoring and diagnostic tools for integration with WLDF.
WLDF was a new feature in WebLogic Server 9.0. WLDF enables dynamic access to server data through standard interfaces, and the volume of data accessed at any given time can be modified without shutting down and restarting the server.
References

• Introduction to Weblogic Diagnostic Framework (WLDF)
• Configuring and using Weblogic Diagnostic Framework