Disallow removing some metadata fields by remove ingest processor

CHANGELOG.md

@@ -137,6 +137,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - [BUG] Fix java.lang.SecurityException in repository-gcs plugin ([#10642](https://github.com/opensearch-project/OpenSearch/pull/10642))
 - Add telemetry tracer/metric enable flag and integ test. ([#10395](https://github.com/opensearch-project/OpenSearch/pull/10395))
 - Add instrumentation for indexing in transport bulk action and transport shard bulk action. ([#10273](https://github.com/opensearch-project/OpenSearch/pull/10273))
+- Disallow removing some metadata fields by remove ingest processor ([#10895](https://github.com/opensearch-project/OpenSearch/pull/10895))
 - Refactor common parts from the Rounding class into a separate 'round' package ([#11023](https://github.com/opensearch-project/OpenSearch/issues/11023))
 - Performance improvement for MultiTerm Queries on Keyword fields ([#7057](https://github.com/opensearch-project/OpenSearch/issues/7057))
 - Disable concurrent aggs for Diversified Sampler and Sampler aggs ([#11087](https://github.com/opensearch-project/OpenSearch/issues/11087))

modules/ingest-common/src/main/java/org/opensearch/ingest/common/RemoveProcessor.java

@@ -33,6 +33,7 @@
 package org.opensearch.ingest.common;
 
 import org.opensearch.core.common.Strings;
+import org.opensearch.index.VersionType;
 import org.opensearch.ingest.AbstractProcessor;
 import org.opensearch.ingest.ConfigurationUtils;
 import org.opensearch.ingest.IngestDocument;
@@ -43,6 +44,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.stream.Collectors;
 
 /**
@@ -79,6 +81,24 @@
                     throw new IllegalArgumentException("field [" + path + "] doesn't exist");
                 }
             }
+            // cannot remove _index, _version and _version_type.
+            if (path.equals(IngestDocument.Metadata.INDEX.getFieldName())
+                || path.equals(IngestDocument.Metadata.VERSION.getFieldName())
+                || path.equals(IngestDocument.Metadata.VERSION_TYPE.getFieldName())) {
+                throw new IllegalArgumentException("cannot remove metadata field [" + path + "]");
+            }
+            // removing _id is disallowed when there's an external version specified in the request
+            String versionType = document.getFieldValue(IngestDocument.Metadata.VERSION_TYPE.getFieldName(), String.class);
+            if (path.equals(IngestDocument.Metadata.ID.getFieldName())
+                && !Objects.equals(versionType, VersionType.toString(VersionType.INTERNAL))) {
+                Long version = document.getFieldValue(IngestDocument.Metadata.VERSION.getFieldName(), Long.class);
+                throw new IllegalArgumentException(
+                    "cannot remove metadata field [_id] when specifying external version for the document, version: "
+                        + version
+                        + ", version_type: "
+                        + versionType
+                );
+            }
             document.removeField(path);
         });
         return document;

modules/ingest-common/src/test/java/org/opensearch/ingest/common/RemoveProcessorTests.java

@@ -32,6 +32,7 @@
 
 package org.opensearch.ingest.common;
 
+import org.opensearch.index.VersionType;
 import org.opensearch.ingest.IngestDocument;
 import org.opensearch.ingest.Processor;
 import org.opensearch.ingest.RandomDocumentPicks;
@@ -40,15 +41,17 @@
 
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 import static org.hamcrest.Matchers.equalTo;
 
 public class RemoveProcessorTests extends OpenSearchTestCase {
 
     public void testRemoveFields() throws Exception {
         IngestDocument ingestDocument = RandomDocumentPicks.randomIngestDocument(random());
-        String field = RandomDocumentPicks.randomExistingFieldName(random(), ingestDocument);
+        String field = RandomDocumentPicks.addRandomField(random(), ingestDocument, randomAlphaOfLength(10));
         Processor processor = new RemoveProcessor(
             randomAlphaOfLength(10),
             null,
@@ -124,4 +127,58 @@ public void testIgnoreMissing() throws Exception {
         processor = new RemoveProcessor.Factory(TestTemplateService.instance()).create(null, processorTag, null, configWithEmptyField);
         processor.execute(ingestDocument);
     }
+
+    public void testRemoveMetadataField() throws Exception {
+        IngestDocument ingestDocument = RandomDocumentPicks.randomIngestDocument(random(), new HashMap<>());
+        List<String> metadataFields = ingestDocument.getMetadata()
+            .keySet()
+            .stream()
+            .map(IngestDocument.Metadata::getFieldName)
+            .collect(Collectors.toList());
+
+        for (String metadataFieldName : metadataFields) {
+            Map<String, Object> config = new HashMap<>();
+            config.put("field", metadataFieldName);
+            String processorTag = randomAlphaOfLength(10);
+            Processor processor = new RemoveProcessor.Factory(TestTemplateService.instance()).create(null, processorTag, null, config);
+            // _if_seq_no and _if_primary_term do not exist in the enriched document, removing them will throw IllegalArgumentException
+            if (metadataFieldName.equals(IngestDocument.Metadata.IF_SEQ_NO.getFieldName())
+                || metadataFieldName.equals(IngestDocument.Metadata.IF_PRIMARY_TERM.getFieldName())) {
+                assertThrows(
+                    "field: [" + metadataFieldName + "] doesn't exist",
+                    IllegalArgumentException.class,
+                    () -> processor.execute(ingestDocument)
+                );
+            } else if (metadataFieldName.equals(IngestDocument.Metadata.INDEX.getFieldName())
+                || metadataFieldName.equals(IngestDocument.Metadata.VERSION.getFieldName())
+                || metadataFieldName.equals(IngestDocument.Metadata.VERSION_TYPE.getFieldName())) {
+                    // _index, _version and _version_type cannot be removed
+                    assertThrows(
+                        "cannot remove metadata field [" + metadataFieldName + "]",
+                        IllegalArgumentException.class,
+                        () -> processor.execute(ingestDocument)
+                    );
+                } else if (metadataFieldName.equals(IngestDocument.Metadata.ID.getFieldName())) {
+                    Long version = ingestDocument.getFieldValue(IngestDocument.Metadata.VERSION.getFieldName(), Long.class);
+                    String versionType = ingestDocument.getFieldValue(IngestDocument.Metadata.VERSION_TYPE.getFieldName(), String.class);
+                    if (!versionType.equals(VersionType.toString(VersionType.INTERNAL))) {
+                        assertThrows(
+                            "cannot remove metadata field [_id] when specifying external version for the document, version: "
+                                + version
+                                + ", version_type: "
+                                + versionType,
+                            IllegalArgumentException.class,
+                            () -> processor.execute(ingestDocument)
+                        );
+                    } else {
+                        processor.execute(ingestDocument);
+                        assertThat(ingestDocument.hasField(metadataFieldName), equalTo(false));
+                    }
+                } else if (metadataFieldName.equals(IngestDocument.Metadata.ROUTING.getFieldName())
+                    && ingestDocument.hasField(IngestDocument.Metadata.ROUTING.getFieldName())) {
+                        processor.execute(ingestDocument);
+                        assertThat(ingestDocument.hasField(metadataFieldName), equalTo(false));
+                    }
+        }
+    }
 }

modules/ingest-common/src/yamlRestTest/resources/rest-api-spec/test/ingest/290_remove_processor.yml

@@ -91,3 +91,139 @@ teardown:
         index: test
         id: 1
   - match: { _source.message: "foo bar baz" }
+
+#Related issue: https://github.com/opensearch-project/OpenSearch/issues/10732
+---
+"Test remove metadata field":
+  - skip:
+      version: " - 2.11.99"
+      reason: "The bug was fixed in 2.12"
+
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "remove" : {
+                  "field" : "{{foo}}"
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      catch: /cannot remove metadata field \[\_index\]/
+      index:
+        index: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: {
+          foo: "_index"
+        }
+
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "remove" : {
+                  "field" : "_version"
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      catch: /cannot remove metadata field \[\_version\]/
+      index:
+        index: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: {
+          foo: "bar"
+        }
+
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "remove" : {
+                  "field" : "_version_type"
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      catch: /cannot remove metadata field \[\_version\_type\]/
+      index:
+        index: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: {
+          foo: "bar"
+        }
+
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "remove" : {
+                  "field" : ["_id", "_routing"]
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      index:
+        index: test
+        id: 1
+        routing: abc
+        pipeline: "my_pipeline"
+        body: { message: "foo bar baz" }
+  - match: { result: created }
+
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "remove" : {
+                  "field" : "_id"
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      catch: /cannot remove metadata field \[\_id\] when specifying external version for the document/
+      index:
+        index: test
+        id: "test_id_10000"
+        pipeline: "my_pipeline"
+        version: 1
+        version_type: "external"
+        body: { message: "foo bar baz" }