src/site/apt/expression-rules.apt

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Expression Rules

  In order to select specified messages, Chainsaw allows you to define an
  expression rule that will match zero or more messages.  These expressions
  can be used to search for messages, or to colorize messages.

Basic Operators

  The basic operators are similar to normal programming operators.  They are:

*---*---*
|| Operator || Meaning
*---*---*
| ! | Not
*---*---*
| != | Not Equal
*---*---*
| == | Equal
*---*---*
| \~= | CASE-INSENSITIVE equals operator
*---*---*
| \|\| | OR
*---*---*
| && | And
*---*---*
| like | REGEXP operator
*---*---*
| exists | Not NULL
*---*---*
| \< | Less Than
*---*---*
| \<= | Less Than or equal
*---*---*
| \> | Greater Than
*---*---*
| \>= | Greater Than or equal
*---*---*

Grouping Expressions

  As with mathematical expressions, ordering/grouping can be enforced by
  using parentheses around the parts to group.

Fields to Match

  Expressions that are made can match on specific fields of a message.  The
  fields that can be matched are as follows:

*---*---*
|| Field | Meaning
*---*---*
| LOGGER | The logger that produced this log message
*---*---*
| LEVEL | The severity of the log message
*---*---*
| CLASS | The class that this log message is from
*---*---*
| FILE | The file that this log message was logged in
*---*---*
| METHOD | The method that produced this log message
*---*---*
| MSG | The log message
*---*---*
| NDC | The Nested Diagnostic Context of this message
*---*---*
| EXCEPTION | The exception in the log message
*---*---*
| TIMESTAMP | When the log message was created
*---*---*
| THREAD | The thread that produced this log message
*---*---*

Examples

  Capture messages at DEBUG level

+--
LEVEL==DEBUG
+--

  Capture message at DEBUG and TRACE levels(trace is less than DEBUG)

+--
LEVEL<=DEBUG
+--

  Capture DEBUG and TRACE messages for the logger named 'com'

+--
LEVEL<=DEBUG && LOGGER==com
+--

  Capture messages that have the string 'specific' in the message

+--
MSG like .*specific.*
+--

  Capture messages that are at INFO or above, or (messages that start with 'Start' or loggers named 'test').

+--
level >= INFO || ( msg like 'Start.*' || logger == 'test' )
+--