IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
« Manage multiline messages Examples of multiline configuration »
Elastic Docs ›Observability Guide [8.2] ›Send data to Elasticsearch ›Elastic Serverless Forwarder for AWS ›Configuration options for Elastic Serverless Forwarder ›Manage multiline messages

Configuration options

edit
Configuration options
edit

You can specify the following options for a specific input in the config.yaml file to control how the Elastic Serverless Forwarder deals with messages that span multiple lines.

inputs:
  - type: "s3-sqs"
    id: "arn:aws:sqs:%REGION%:%ACCOUNT%:%QUEUENAME%"
    multiline:
      type: pattern
      pattern: '^\\['
      negate: true
      match: after
    outputs:
      - type: "elasticsearch"
        args:
          elasticsearch_url: "arn:aws:secretsmanager:eu-central-1:123456789:secret:es_url"
          username: "arn:aws:secretsmanager:eu-west-1:123456789:secret:es_secrets:username"
          password: "arn:aws:secretsmanager:eu-west-1:123456789:secret:es_secrets:password"
          es_datastream_name: "logs-generic-default"

The forwarder takes all the lines that do not start with [ and combines them with the previous line that does. For example, you could use this configuration to join the following lines of a multiline message into a single event:

[beat-logstash-some-name-832-2015.11.28] IndexNotFoundException[no such index]
    at org.elasticsearch.cluster.metadata.IndexNameExpressionResolver$WildcardExpressionResolver.resolve(IndexNameExpressionResolver.java:566)
    at org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.concreteIndices(IndexNameExpressionResolver.java:133)
    at org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.concreteIndices(IndexNameExpressionResolver.java:77)
    at org.elasticsearch.action.admin.indices.delete.TransportDeleteIndexAction.checkBlock(TransportDeleteIndexAction.java:75)

Note that you should escape the opening square bracket ([) in the regular expression, because it specifies a character class i.e. a set of characters that you wish to match. You also have to escape the backslash (\) used for escaping the opening square bracket as raw strings are not used. Thus, ^\\[ will produce the required regular expression upon compiling.

inputs.[].multiline.type defines which aggregation method to use. The default is pattern. The other options are count, which enables you to aggregate a constant number of lines, and while_pattern, which aggregates lines by pattern without matching options.

inputs.[].multiline.pattern differs from the patterns supported by Logstash. See Python’s 3.9 regular expression syntax for a list of supported regexp patterns. Depending on how you configure other multiline options, lines that match the specified regular expression are considered either continuations of a previous line or the start of a new multiline event.

inputs.[].multiline.negate defines whether the pattern is negated. The default is false. This setting works only with pattern and while_pattern types.

inputs.[].multiline.match changes the grouping of multiple lines according to the schema below (works only with pattern type):

Setting for negate

Setting for match

Result

Example pattern: ^b

false

after

Consecutive lines that match the pattern are appended to the previous line that doesn’t match.

Lines a b b c b b become "abb" and "cbb"

false

before

Consecutive lines that match the pattern are prepended to the next line that doesn’t match.

Lines b b a b b c become "bba" and "bbc"

true

after

Consecutive lines that don’t match the pattern are appended to the previous line that does match.

Lines b a c b d e become "bac" and "bde"

false

before

Consecutive lines that don’t match the pattern are prepended to the next line that does match.

Lines a c b d e b become "acb" and "deb"

The after setting is equivalent to previous in Logstash, and before is equivalent to next.

inputs.[].multiline.flush_pattern specifies a regular expression, in which the current multiline will be flushed from memory, ending the multiline-message. Works only with pattern type.

inputs.[].multiline.max_lines defines the maximum number of lines that can be combined into one event. If the multiline message contains more than max_lines, any additional lines are truncated from the event. The default is 500.

inputs.[].multiline.max_bytes defines the maximum number of bytes that can be combined into one event. If the multiline message contains more than max_bytes, any additional content is truncated from the event. The default is 10485760.

inputs.[].multiline.count_lines defines the number of lines to aggregate into a single event. Works only with count type.

inputs.[].multiline.skip_newline defined whether multiline events must be concatenated, stripping the line separator. If set to true, the line separator will be stripped. The default is false.

« Manage multiline messages Examples of multiline configuration »