Introduce system ingest pipeline.

CHANGELOG.md

@@ -18,6 +18,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Allow to get the search request from the QueryCoordinatorContext ([#17818](https://github.com/opensearch-project/OpenSearch/pull/17818))
 - Improve sort-query performance by retaining the default `totalHitsThreshold` for approximated `match_all` queries ([#18189](https://github.com/opensearch-project/OpenSearch/pull/18189))
 - Enable testing for ExtensiblePlugins using classpath plugins ([#16908](https://github.com/opensearch-project/OpenSearch/pull/16908))
+- Introduce system generated ingest pipeline ([#17817](https://github.com/opensearch-project/OpenSearch/pull/17817)))
 
 ### Changed
 

server/src/internalClusterTest/java/org/opensearch/index/FinalPipelineIT.java

@@ -111,7 +111,7 @@ public void testFinalPipelineCantChangeDestination() {
             IllegalStateException.class,
             () -> client().prepareIndex("index").setId("1").setSource(Collections.singletonMap("field", "value")).get()
         );
-        assertThat(e, hasToString(containsString("final pipeline [final_pipeline] can't change the target index")));
+        assertThat(e, hasToString(containsString("FINAL pipeline [final_pipeline] can't change the target index")));
     }
 
     public void testFinalPipelineOfOldDestinationIsNotInvoked() {

server/src/main/java/org/opensearch/action/bulk/TransportBulkAction.java

@@ -251,7 +251,7 @@ protected void doInternalExecute(Task task, BulkRequest bulkRequest, String exec
             IndexRequest indexRequest = getIndexWriteRequest(actionRequest);
             if (indexRequest != null) {
                 // Each index request needs to be evaluated, because this method also modifies the IndexRequest
-                boolean indexRequestHasPipeline = IngestService.resolvePipelines(actionRequest, indexRequest, metadata);
+                boolean indexRequestHasPipeline = ingestService.resolvePipelines(actionRequest, indexRequest, metadata);
                 hasIndexRequestsWithPipelines |= indexRequestHasPipeline;
             }
 

server/src/main/java/org/opensearch/action/index/IndexRequest.java

@@ -123,6 +123,7 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
 
     private String pipeline;
     private String finalPipeline;
+    private String systemIngestPipeline;
 
     private boolean isPipelineResolved;
 
@@ -158,6 +159,9 @@ public IndexRequest(@Nullable ShardId shardId, StreamInput in) throws IOExceptio
         versionType = VersionType.fromValue(in.readByte());
         pipeline = in.readOptionalString();
         finalPipeline = in.readOptionalString();
+        if (in.getVersion().onOrAfter(Version.V_3_1_0)) {
+            systemIngestPipeline = in.readOptionalString();
+        }
         isPipelineResolved = in.readBoolean();
         isRetry = in.readBoolean();
         autoGeneratedTimestamp = in.readLong();
@@ -314,6 +318,21 @@ public String getPipeline() {
         return this.pipeline;
     }
 
+    /**
+     * Sets the system ingest pipeline to be executed before indexing the document
+     */
+    public IndexRequest setSystemIngestPipeline(final String systemIngestPipeline) {
+        this.systemIngestPipeline = systemIngestPipeline;
+        return this;
+    }
+
+    /**
+     * Returns the system ingest pipeline to be executed before indexing the document
+     */
+    public String getSystemIngestPipeline() {
+        return this.systemIngestPipeline;
+    }
+
     /**
      * Sets the final ingest pipeline to be executed before indexing the document.
      *
@@ -668,6 +687,9 @@ private void writeBody(StreamOutput out) throws IOException {
         out.writeByte(versionType.getValue());
         out.writeOptionalString(pipeline);
         out.writeOptionalString(finalPipeline);
+        if (out.getVersion().onOrAfter(Version.V_3_1_0)) {
+            out.writeOptionalString(systemIngestPipeline);
+        }
         out.writeBoolean(isPipelineResolved);
         out.writeBoolean(isRetry);
         out.writeLong(autoGeneratedTimestamp);

server/src/main/java/org/opensearch/common/settings/ClusterSettings.java

@@ -413,6 +413,7 @@ public void apply(Settings value, Settings current, Settings previous) {
                 ClusterService.USER_DEFINED_METADATA,
                 ClusterManagerService.CLUSTER_MANAGER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,
                 IngestService.MAX_NUMBER_OF_INGEST_PROCESSORS,
+                IngestService.SYSTEM_INGEST_PIPELINE_ENABLED,
                 SearchService.DEFAULT_SEARCH_TIMEOUT_SETTING,
                 SearchService.DEFAULT_ALLOW_PARTIAL_SEARCH_RESULTS,
                 TransportSearchAction.SHARD_COUNT_LIMIT_SETTING,

server/src/main/java/org/opensearch/ingest/AbstractBatchingSystemProcessor.java

@@ -0,0 +1,81 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.ingest;
+
+import java.util.Map;
+
+/**
+ * Abstract base class for batch system generated processors.
+ *
+ * System processors should not be used in the regular ingest pipelines.
+ *
+ * @opensearch.internal
+ */
+public abstract class AbstractBatchingSystemProcessor extends AbstractBatchingProcessor {
+    protected AbstractBatchingSystemProcessor(String tag, String description, int batchSize) {
+        super(tag, description, batchSize);
+    }
+
+    @Override
+    public boolean isSystemGenerated() {
+        return true;
+    }
+
+    /**
+     * Factory class for creating {@link AbstractBatchingSystemProcessor} instances systematically.
+     *
+     * Since the processor config is generated based on the index config so the batch size info should also be defined
+     * as part of it. And different processors can have their own logic to decide the batch size so let each
+     * implementation of the newProcessor to handle it.
+     *
+     * @opensearch.internal
+     */
+    public abstract static class Factory implements Processor.Factory {
+        final String processorType;
+
+        protected Factory(String processorType) {
+            this.processorType = processorType;
+        }
+
+        @Override
+        public boolean isSystemGenerated() {
+            return true;
+        }
+
+        /**
+         * Creates a new processor instance. It will be invoked systematically.
+         *
+         * @param processorFactories The processor factories.
+         * @param tag                 The processor tag.
+         * @param description         The processor description.
+         * @param config              The processor configuration.
+         * @return The new AbstractBatchProcessor instance.
+         * @throws Exception If the processor could not be created.
+         */
+        @Override
+        public AbstractBatchingSystemProcessor create(
+            Map<String, Processor.Factory> processorFactories,
+            String tag,
+            String description,
+            Map<String, Object> config
+        ) throws Exception {
+            return newProcessor(tag, description, config);
+        }
+
+        /**
+         * Returns a new processor instance. It will be invoked systematically.
+         *
+         * @param tag tag of the processor
+         * @param description description of the processor
+         * @param config configuration of the processor
+         * @return a new batch processor instance
+         */
+        protected abstract AbstractBatchingSystemProcessor newProcessor(String tag, String description, Map<String, Object> config);
+    }
+}

server/src/main/java/org/opensearch/ingest/IndexRequestWrapper.java

@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.ingest;
+
+import org.opensearch.action.DocWriteRequest;
+import org.opensearch.action.index.IndexRequest;
+
+import java.util.List;
+
+/**
+ * A wrapper for the index request to help execute the ingest pipelines.
+ */
+public class IndexRequestWrapper {
+    /**
+     * slot of the IndexRequestWrapper is the index of the request in the list of the requests.
+     * It can be used to map the ingested result or exception to right index request.
+     */
+    private final int slot;
+    private final IndexRequest indexRequest;
+    private final DocWriteRequest<?> actionRequest;
+    private final List<IngestPipelineInfo> pipelineInfoList;
+
+    public IndexRequestWrapper(
+        int slot,
+        IndexRequest indexRequest,
+        DocWriteRequest<?> actionRequest,
+        List<IngestPipelineInfo> pipelineInfoList
+    ) {
+        this.slot = slot;
+        this.indexRequest = indexRequest;
+        this.actionRequest = actionRequest;
+        this.pipelineInfoList = pipelineInfoList;
+    }
+
+    public int getSlot() {
+        return slot;
+    }
+
+    public IndexRequest getIndexRequest() {
+        return indexRequest;
+    }
+
+    public DocWriteRequest<?> getActionRequest() {
+        return actionRequest;
+    }
+
+    public List<IngestPipelineInfo> getIngestPipelineInfoList() {
+        return pipelineInfoList;
+    }
+}

server/src/main/java/org/opensearch/ingest/IngestPipelineInfo.java

@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.ingest;
+
+import reactor.util.annotation.NonNull;
+
+/**
+ * Ingest pipeline info help hold the pipeline id and type.
+ */
+public class IngestPipelineInfo {
+    private final String pipelineId;
+    private final IngestPipelineType type;
+
+    public IngestPipelineInfo(final @NonNull String pipelineId, final @NonNull IngestPipelineType type) {
+        this.pipelineId = pipelineId;
+        this.type = type;
+    }
+
+    public String getPipelineId() {
+        return pipelineId;
+    }
+
+    public IngestPipelineType getType() {
+        return type;
+    }
+
+    @Override
+    public String toString() {
+        return pipelineId + ":" + type.name();
+    }
+}

server/src/main/java/org/opensearch/ingest/IngestPipelineType.java

@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.ingest;
+
+/**
+ * An enum for the ingest pipeline type
+ */
+public enum IngestPipelineType {
+    /**
+     * Default pipeline is the pipeline provided through the index request or defined in
+     * the index settings as the default pipeline.
+     */
+    DEFAULT,
+    /**
+     * Final pipeline is the one defined in the index settings as the final pipeline.
+     */
+    FINAL,
+    /**
+     * System final pipeline is a systematically generated pipeline which will be executed after the
+     * user defined final pipeline.
+     */
+    SYSTEM_FINAL
+}