Examples of multiline configuration
editExamples of multiline configuration
editThe examples in this section cover the following use cases:
- Combining a Java stack trace into a single event
- Combining C-style line continuations into a single event
- Combining multiple lines from time-stamped events
Java stack traces
editJava stack traces consist of multiple lines, with each line after the initial line beginning with whitespace, as in this example:
Exception in thread "main" java.lang.NullPointerException at com.example.myproject.Book.getTitle(Book.java:16) at com.example.myproject.Author.getBookTitles(Author.java:25) at com.example.myproject.Bootstrap.main(Bootstrap.java:14)
To consolidate these lines into a single event in Filebeat, use the following multiline configuration:
multiline.pattern: '^[[:space:]]' multiline.negate: false multiline.match: after
This configuration merges any line that begins with whitespace up to the previous line.
Here’s a Java stack trace that presents a slightly more complex example:
Exception in thread "main" java.lang.IllegalStateException: A book has a null property at com.example.myproject.Author.getBookIds(Author.java:38) at com.example.myproject.Bootstrap.main(Bootstrap.java:14) Caused by: java.lang.NullPointerException at com.example.myproject.Book.getId(Book.java:22) at com.example.myproject.Author.getBookIds(Author.java:35) ... 1 more
To consolidate these lines into a single event in Filebeat, use the following multiline configuration:
multiline.pattern: '^[[:space:]]+(at|\.{3})\b|^Caused by:' multiline.negate: false multiline.match: after
In this example, the pattern matches the following lines:
-
a line that begins with spaces followed by the word
at
or...
-
a line that begins with the words
Caused by:
Line continuations
editSeveral programming languages use the backslash (\
) character at the end of a line to denote that the line continues,
as in this example:
printf ("%10.10ld \t %10.10ld \t %s\ %f", w, x, y, z );
To consolidate these lines into a single event in Filebeat, use the following multiline configuration:
multiline.pattern: '\\$' multiline.negate: false multiline.match: before
This configuration merges any line that ends with the \
character with the line that follows.
Timestamps
editActivity logs from services such as Elasticsearch typically begin with a timestamp, followed by information on the specific activity, as in this example:
[2015-08-24 11:49:14,389][INFO ][env ] [Letha] using [1] data paths, mounts [[/ (/dev/disk1)]], net usable_space [34.5gb], net total_space [118.9gb], types [hfs]
To consolidate these lines into a single event in Filebeat, use the following multiline configuration:
multiline.pattern: '^\[[0-9]{4}-[0-9]{2}-[0-9]{2}' multiline.negate: true multiline.match: after
This configuration uses the negate: true
and match: after
settings to specify that any line that does not match the
specified pattern belongs to the previous line.
Application events
editSometimes your application logs contain events, that begin and end with custom markers, such as the following example:
[2015-08-24 11:49:14,389] Start new event [2015-08-24 11:49:14,395] Content of processing something [2015-08-24 11:49:14,399] End event
To consolidate this as a single event in Filebeat, use the following multiline configuration:
multiline.pattern: 'Start new event' multiline.negate: true multiline.match: after multiline.flush_pattern: 'End event'
The flush_pattern
option, specifies a regex at which the current multiline will be flushed. If you think of the pattern
option specifying the beginning of an event, the flush_pattern
option will specify the end or last line of the event.