Pipeline testing in Elasticsearch - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this pipeline test response?

Given this Elasticsearch ingest pipeline test response, what is the value of doc['field1'] after processing?

{
  "docs": [
    {
      "doc": {
        "_index": "test-index",
        "_id": "1",
        "_source": {
          "field1": "new_value",
          "field2": "value2"
        }
      },
      "processor_results": [
        {
          "set": {
            "field": "field1",
            "value": "new_value"
          }
        }
      ]
    }
  ]
}

A "new_value"

B "value1"

C null

D "value2"

💡 Hint

Look at the processor_results to see what the set processor does.

The set processor changes field1 to "new_value" during pipeline processing.

❓ Predict Output

intermediate

What error does this pipeline test raise?

Consider this pipeline test response snippet:

{
  "docs": [
    {
      "error": {
        "type": "exception",
        "reason": "processor [uppercase] failed",
        "caused_by": {
          "type": "illegal_argument_exception",
          "reason": "field [nonexistent_field] not present"
        }
      }
    }
  ]
}

What error type caused the failure?

A index_not_found_exception

B illegal_argument_exception

C parse_exception

D null_pointer_exception

💡 Hint

Check the caused_by field for the root cause.

The error is an illegal_argument_exception because the processor tried to access a field that does not exist.

🧠 Conceptual

advanced

Which option correctly describes the purpose of pipeline testing in Elasticsearch?

What is the main goal of using the _simulate API or pipeline test API in Elasticsearch?

A To monitor cluster health and node status

B To delete documents from the index based on pipeline rules

C To test how documents are transformed by the ingest pipeline before indexing

D To backup and restore pipeline configurations

💡 Hint

Think about what happens when you simulate a pipeline with sample documents.

Pipeline testing simulates document processing to verify transformations before actual indexing.

❓ Predict Output

advanced

What is the number of documents processed successfully in this pipeline test?

Given this pipeline test response:

{
  "docs": [
    {"doc": {"_id": "1"}},
    {"doc": {"_id": "2"}},
    {"error": {"type": "exception", "reason": "failed"}},
    {"doc": {"_id": "4"}}
  ]
}

How many documents were processed without error?

A 4

B 2

C 1

D 3

💡 Hint

Count the entries with a doc key and no error.

Three documents have doc and no error, so 3 succeeded.

🚀 Application

expert

Which pipeline test input will produce this output field value?

Given a pipeline with a gsub processor that replaces all digits with "#" in field1, which input document will produce field1 value "abc###def" after processing?

A {"field1": "abc123def"}

B {"field1": "abc12def"}

C {"field1": "abcdef"}

D {"field1": "abc1def"}

💡 Hint

Count how many digits are replaced by "#" in the output.

The output has three "#" characters, so the input must have three digits.