Lowercase
The lowercase processor converts all the text in a specific field to lowercase letters. The following is the syntax for the lowercase processor:
{
"lowercase": {
"field": "field_name"
}
}
Configuration parameters
The following table lists the required and optional parameters for the lowercase processor.
| Name | Required | Description |
|---|---|---|
field | Required | The name of the field that contains the data to be converted. Supports template snippets. |
description | Optional | A brief description of the processor. |
if | Optional | A condition for running this processor. |
ignore_failure | Optional | If set to true, failures are ignored. Default is false. |
on_failure | Optional | A list of processors to run if the processor fails. |
ignore_missing | Optional | Specifies whether the processor should ignore documents that do not have the specified field. Default is false. |
tag | Optional | An identifier tag for the processor. Useful for debugging to distinguish between processors of the same type. |
target_field | Optional | The name of the field in which to store the parsed data. Default is field. By default, field is updated in place. |
Using the processor
Follow these steps to use the processor in a pipeline.
Step 1: Create a pipeline.
The following query creates a pipeline, named lowercase-title, that uses the lowercase processor to lowercase the title field of a document:
PUT _ingest/pipeline/lowercase-title
{
"description" : "Pipeline that lowercases the title field",
"processors" : [
{
"lowercase" : {
"field" : "title"
}
}
]
}
Step 2 (Optional): Test the pipeline.
It is recommended that you test your pipeline before you ingest documents.
To test the pipeline, run the following query:
POST _ingest/pipeline/lowercase-title/_simulate
{
"docs": [
{
"_index": "testindex1",
"_id": "1",
"_source": {
"title": "WAR AND PEACE"
}
}
]
}
Response
The following example response confirms that the pipeline is working as expected:
{
"docs": [
{
"doc": {
"_index": "testindex1",
"_id": "1",
"_source": {
"title": "war and peace"
},
"_ingest": {
"timestamp": "2023-08-22T17:39:39.872671834Z"
}
}
}
]
}
Step 3: Ingest a document.
The following query ingests a document into an index named testindex1:
PUT testindex1/_doc/1?pipeline=lowercase-title
{
"title": "WAR AND PEACE"
}
Step 4 (Optional): Retrieve the document.
To retrieve the document, run the following query:
GET testindex1/_doc/1