Expand JSON fields - Simple Log Service - Alibaba Cloud Documentation Center

You can use the processor_json plug-in to expand JSON fields. This topic describes the parameters of the processor_json plug-in and provides an example on how to configure the plug-in.

Important

Form configuration: Available when collecting text logs and container stdout and stderr.
Editor configuration in JSON: Not available when collecting text logs.

Entry point

If you want to use a Logtail plug-in to process logs, you can add a Logtail plug-in configuration when you create or modify a Logtail configuration. For more information, see Overview of Logtail plug-ins for data processing.

Usage notes

Important

Only Logtail V0.16.28 and later support the processor_json plug-in.

Form configuration

Parameters

Set Processor Type to Expand JSON Field. Then, configure other parameters based on the following table.

Parameter	Description
Original Field	The name of the original field to expand.
JSON Expansion Depth	The depth of JSON expansion. Default value: 0. This value indicates that the depth of JSON expansion is unlimited. If the value is n, the depth of JSON expansion is n.
Character to Concatenate Expanded Keys	The character that is used to connect expanded keys. The default value is an underscore (_).
Name Prefix of Expanded Keys	The prefix that is added to the names of expanded keys.
Expand Array	Specifies whether to expand the array. Only Logtail 1.8.0 and later support this parameter.
Retain Original Field	Specifies whether to retain the original field in the new log that is obtained after parsing.
Report Original Field Missing Error	Specifies whether to report an error if the raw log does not contain the original field.
Use Name of Original Field as Name Prefix of Expanded Keys	Specifies whether to add the name of the original field as a prefix to all expanded keys.
Retain Raw Logs If Parsing Fails	Specifies whether to retain the raw log if the raw log fails to be parsed.

Configuration example
The following example shows how to expand the JSON field s_key and use j as the prefix, with the original field name s_key as the field name after JSON expansion.
- Raw log (file path read by Logtail)
```
{"s_key":"{\"k1\":{\"k2\":{\"k3\":{\"k4\":{\"k51\":\"51\",\"k52\":\"52\"},\"k41\":\"41\"}}}}"}
```
- Logtail plug-in configuration for data processing
- Result

Editor configuration in JSON

Parameters

Set type to processor_json. Then, configure other parameters in detail based on the following table.

Parameter	Type	Required	Description
SourceKey	String	Yes	The name of the original field to expand.
NoKeyError	Boolean	No	Specifies whether to report an error if the raw log does not contain the original field. Valid values: true (default): reports an error. false: does not report an error.
ExpandDepth	Int	No	The depth of JSON expansion. Default value: 0. This value indicates that the depth of JSON expansion is unlimited. If the value is n, the depth of JSON expansion is n.
ExpandConnector	String	No	The character that is used to connect expanded keys. The default value is an underscore (_).
Prefix	String	No	The prefix that is added to the names of expanded keys.
KeepSource	Boolean	No	Specifies whether to retain the original field in the new log that is obtained after parsing. Valid values: true (default): retains the original field. false: does not retain the original field.
UseSourceKeyAsPrefix	Boolean	No	Specifies whether to add the name of the original field as a prefix to all expanded keys.
KeepSourceIfParseError	Boolean	No	Specifies whether to retain the raw log if the raw log fails to be parsed. Valid values: true (default): retains the raw log. false: does not retain the raw log.
ExpandArray	Boolean	No	Specifies whether to expand the array. Only Logtail 1.8.0 and later support this parameter. false (default): does not expand the array. true: expands the array. For example, `{"k":["1","2"]}` is expanded to `{"k[0]":"1","k[1]":"2"}`.

Configuration example

The following example shows how to expand the JSON field s_key and use j as the prefix, with the original field name s_key as the field name after JSON expansion.

Raw log (file path read by Logtail)

{"s_key":"{\"k1\":{\"k2\":{\"k3\":{\"k4\":{\"k51\":\"51\",\"k52\":\"52\"},\"k41\":\"41\"}}}}"}

Logtail plug-in configuration for data processing

{
  "processors":[
    {
      "type":"processor_json",
      "detail": {
        "SourceKey": "content",
        "NoKeyError":true,
        "ExpandDepth":0,
        "ExpandConnector":"-",
        "Prefix":"j",
        "KeepSource": false,
        "UseSourceKeyAsPrefix": true
      }
    }
  ]
}

Result