multiline

The multiline parser plugin parses multiline logs. This plugin is the multiline version of regexp parser.

The multiline parser parses log with formatN and format_firstline parameters. format_firstline is for detecting the start line of the multiline log. formatN, where N's range is [1..20], is the list of Regexp format for multiline log.

Unlike other parser plugins, this plugin needs special code in input plugin e.g. handle format_firstline. So, currently, in_tail plugin works with multiline but other input plugins do not work with it.

Parameters

See Parse Section Configurations.

format_firstline

Specifies the regexp pattern for the start line of multiple lines. Input plugin can skip the logs until format_firstline is matched. Default is nil.

If format_firstline is not specified, the input plugin should store the unmatched new lines in the temporary buffer and try to match the buffered logs with each new line.

formatN

type	default	version
string	nil	0.14.0

It is a required parameter.

Specifies the regexp patterns. For readability, you can separate the regexp patterns into multiple formatN parameters. See the Rails Log's example below. These patterns are joined and then construct a regexp pattern with multiline mode.

Example

Rails Log

With this configuration:

<parse>
  @type multiline
  format_firstline /^Started/
  format1 /Started (?<method>[^ ]+) "(?<path>[^"]+)" for (?<host>[^ ]+) at (?<time>[^ ]+ [^ ]+ [^ ]+)\n/
  format2 /Processing by (?<controller>[^\u0023]+)\u0023(?<controller_method>[^ ]+) as (?<format>[^ ]+?)\n/
  format3 /(  Parameters: (?<parameters>[^ ]+)\n)?/
  format4 /  Rendered (?<template>[^ ]+) within (?<layout>.+) \([\d\.]+ms\)\n/
  format5 /Completed (?<code>[^ ]+) [^ ]+ in (?<runtime>[\d\.]+)ms \(Views: (?<view_runtime>[\d\.]+)ms \| ActiveRecord: (?<ar_runtime>[\d\.]+)ms\)/
</parse>

This incoming event:

Started GET "/users/123/" for 127.0.0.1 at 2013-06-14 12:00:11 +0900
Processing by UsersController#show as HTML
  Parameters: {"user_id"=>"123"}
  Rendered users/show.html.erb within layouts/application (0.3ms)
Completed 200 OK in 4ms (Views: 3.2ms | ActiveRecord: 0.0ms)

is parsed as:

time:
1371178811 (2013-06-14 12:00:11 +0900)

record:
{
  "method"           :"GET",
  "path"             :"/users/123/",
  "host"             :"127.0.0.1",
  "controller"       :"UsersController",
  "controller_method":"show",
  "format"           :"HTML",
  "parameters"       :"{ \"user_id\":\"123\"}",
  ...
}

Java Stacktrace Log

With this configuration:

<parse>
  @type multiline
  format_firstline /\d{4}-\d{1,2}-\d{1,2}/
  format1 /^(?<time>\d{4}-\d{1,2}-\d{1,2} \d{1,2}:\d{1,2}:\d{1,2}) \[(?<thread>.*)\] (?<level>[^\s]+)(?<message>.*)/
</parse>

These incoming events:

2013-3-03 14:27:33 [main] INFO  Main - Start
2013-3-03 14:27:33 [main] ERROR Main - Exception
javax.management.RuntimeErrorException: null
    at Main.main(Main.java:16) ~[bin/:na]
2013-3-03 14:27:33 [main] INFO  Main - End

are parsed as:

time:
2013-03-03 14:27:33 +0900
record:
{
  "thread" :"main",
  "level"  :"INFO",
  "message":"  Main - Start"
}

time:
2013-03-03 14:27:33 +0900
record:
{
  "thread" :"main",
  "level"  :"ERROR",
  "message":" Main - Exception\njavax.management.RuntimeErrorException: null\n    at Main.main(Main.java:16) ~[bin/:na]"
}

time:
2013-03-03 14:27:33 +0900
record:
{
  "thread" :"main",
  "level"  :"INFO",
  "message":"  Main - End"
}

If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is an open-source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.