Title:  Patterns for Logging Diagnostic Messages

Neil B. Harrison

Bell Laboratories
11900 N. Pecos st.
Denver CO 80234
(303) 538-1541

nbh@dr.att.com


Most software systems report errors to the user, and many provide additional
diagnostic information to assist is troubleshooting.  Transaction-
oriented systems lend themselves to common approaches to logging
diagnostic messages.  These approaches are embodied in three patterns.
The first pattern, Diagnostic Logger, separates logging from the rest
of the software, and lays the groundwork for the other patterns.  The
second pattern, Transactional Buckets, provides association of diagnostics
with the correct transactions.  The third pattern, Diagnostic Types, helps
ensure uniformity of presentation for all diagnostics.  It also allows
the software to handle various diagnostics differently, depending on
characteristics such as error severity.