Pipeline testing in Elasticsearch

Introduction

Pipeline testing helps you check if your data processing steps work correctly before using them in real searches. It saves time and avoids errors.

You want to see how your data changes after each processing step.

You need to verify that your pipeline extracts the right information.

You want to test your pipeline with sample data before applying it to all data.

You want to debug why your data is not indexed as expected.

You want to confirm that your pipeline handles edge cases correctly.

Syntax

Elasticsearch

POST _ingest/pipeline/_simulate
{
  "pipeline": {
    "description": "My test pipeline",
    "processors": [
      { "set": { "field": "field1", "value": "value1" } },
      { "uppercase": { "field": "field1" } }
    ]
  },
  "docs": [
    { "_source": { "field1": "hello" } }
  ]
}

The _simulate API runs your pipeline on sample documents without indexing them.

You can define the pipeline inline or refer to an existing pipeline by ID.

Examples

This example sets a new field status to "active" for the sample document.

Elasticsearch

POST _ingest/pipeline/_simulate
{
  "pipeline": {
    "processors": [
      { "set": { "field": "status", "value": "active" } }
    ]
  },
  "docs": [
    { "_source": { "user": "alice" } }
  ]
}

This example tests an existing pipeline called my_pipeline with a sample document.

Elasticsearch

POST _ingest/pipeline/my_pipeline/_simulate
{
  "docs": [
    { "_source": { "message": "hello world" } }
  ]
}

Sample Program

This program tests a pipeline that converts the message field to uppercase.

Elasticsearch

POST _ingest/pipeline/_simulate
{
  "pipeline": {
    "description": "Test pipeline to uppercase a field",
    "processors": [
      { "uppercase": { "field": "message" } }
    ]
  },
  "docs": [
    { "_source": { "message": "hello elasticsearch" } }
  ]
}

Important Notes

Use pipeline testing to avoid indexing bad data.

You can test multiple documents at once by adding more items in the docs array.

Remember that _simulate does not save data; it only shows results.

Summary

Pipeline testing runs your data processing steps on sample data without saving it.

It helps you check and fix your pipeline before real use.

You can test inline pipelines or existing ones by ID.