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    Simple Log Service:Extension plug-in: Pack fields

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    Simple Log Service:Extension plug-in: Pack fields

    Last Updated:Aug 22, 2025

    When you use Logtail to collect logs, you can use the processor_packjson plug-in to pack one or more fields into a field in JSON object format. This topic describes the parameters of the processor_packjson plug-in and provides configuration examples.

    Limits

    Text logs and container standard output support only form-based configuration. Other input plugins support only JSON configuration.

    Entry point

    To use a Logtail plugin to process logs, you can add a plugin configuration when you create or modify a Logtail collection configuration. For more information, see Overview of Logtail plugins for data processing.

    Configuration description

    Important

    Logtail 0.16.28 and later supports the processor_packjson plug-in.

    Configure the plug-in using the form

    • Parameters

      Set Processor Type to Pack Fields. The following table describes the parameters.

      Parameter

      Description

      Source Fields

      The source fields to pack.

      Destination Field

      The destination field after packing.

      Keep Source Fields

      Select this option to keep the source fields in the parsed log.

      Alarm On Missing Source Fields

      Select this option to report an error if the specified source fields do not exist in the raw log.

    • Example

      The following example shows how to pack the a and b fields into the d_key JSON field:

      • Raw log

        "a":"1"
"b":"2"

      • Logtail plug-in configuration 打包字段

      • Processing result 

        "a":"1"
"b":"2"
"d_key":"{\"a\":\"1\",\"b\":\"2\"}"

    Configure the plug-in using JSON

    • Parameters

      Set type to processor_packjson. The following table describes the parameters in the detail object.

      Parameter

      Type

      Required

      Description

      SourceKeys

      Array of strings

      Yes

      The source fields to pack.

      DestKey

      String

      No

      The destination field after packing.

      KeepSource

      Boolean

      No

      Specifies whether to keep the source fields in the parsed log. Valid values:

      • true (default)

      • false

      AlarmIfIncomplete

      Boolean

      No

      Specifies whether to report an error if the specified source fields do not exist in the raw log. Valid values:

      • true (default value): Reports an error.

      • false

    • Example

      The following example shows how to pack the a and b fields into the d_key JSON field:

      • Raw log

        "a":"1"
"b":"2"

      • Logtail plug-in configuration 

        {
  "processors":[
    {
      "type":"processor_packjson",
      "detail": {
        "SourceKeys": ["a","b"],
        "DestKey":"d_key",
        "KeepSource":true,
        "AlarmIfEmpty":true
      }
    }
  ]
}

      • Processing result 

        "a":"1"
"b":"2"
"d_key":"{\"a\":\"1\",\"b\":\"2\"}"

    References