Pass pipeline creation source as enum

Thanks to @dblock for the suggestion to pass the pipeline creation
source in a way that accounts for possible future pipeline sources (and
lets us distinguish between actual named pipeline creation and the
validation create() that executes before we write a pipeline definition
to cluster state).

Signed-off-by: Michael Froh <froh@amazon.com>

modules/search-pipeline-common/src/main/java/org/opensearch/search/pipeline/common/ScriptRequestProcessor.java

@@ -29,7 +29,8 @@
 import org.opensearch.search.pipeline.common.helpers.SearchRequestMap;
 
 import java.io.InputStream;
-import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import static org.opensearch.ingest.ConfigurationUtils.newConfigurationException;
@@ -127,6 +128,8 @@ SearchScript getPrecompiledSearchScript() {
      * Factory class for creating {@link ScriptRequestProcessor}.
      */
     public static final class Factory implements Processor.Factory<SearchRequestProcessor> {
+        private static final List<String> SCRIPT_CONFIG_KEYS = List.of("id", "source", "inline", "lang", "params", "options");
+
         private final ScriptService scriptService;
 
         /**
@@ -155,16 +158,21 @@ public ScriptRequestProcessor create(
             String description,
             Map<String, Object> config
         ) throws Exception {
+            Map<String, Object> scriptConfig = new HashMap<>();
+            for (String key : SCRIPT_CONFIG_KEYS) {
+                Object val = config.remove(key);
+                if (val != null) {
+                    scriptConfig.put(key, val);
+                }
+            }
             try (
-                XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent).map(config);
+                XContentBuilder builder = XContentBuilder.builder(JsonXContent.jsonXContent).map(scriptConfig);
                 InputStream stream = BytesReference.bytes(builder).streamInput();
                 XContentParser parser = XContentType.JSON.xContent()
                     .createParser(NamedXContentRegistry.EMPTY, LoggingDeprecationHandler.INSTANCE, stream)
             ) {
                 Script script = Script.parse(parser);
 
-                Arrays.asList("id", "source", "inline", "lang", "params", "options").forEach(config::remove);
-
                 // verify script is able to be compiled before successfully creating processor.
                 SearchScript searchScript = null;
                 try {

modules/search-pipeline-common/src/yamlRestTest/resources/rest-api-spec/test/search_pipeline/50_script_processor.yml

@@ -17,6 +17,7 @@ teardown:
             "request_processors": [
               {
                 "script" : {
+                  "tag": "empty_script",
                   "lang": "painless",
                   "source" : ""
                 }
@@ -38,6 +39,7 @@ teardown:
             "request_processors": [
               {
                 "script" : {
+                  "tag": "working",
                   "lang" : "painless",
                   "source" : "ctx._source['size'] += 10; ctx._source['from'] = ctx._source['from'] <= 0 ? ctx._source['from'] : ctx._source['from'] - 1 ; ctx._source['explain'] = !ctx._source['explain']; ctx._source['version'] = !ctx._source['version']; ctx._source['seq_no_primary_term'] = !ctx._source['seq_no_primary_term']; ctx._source['track_scores'] = !ctx._source['track_scores']; ctx._source['track_total_hits'] = 1; ctx._source['min_score'] -= 0.9; ctx._source['terminate_after'] += 2; ctx._source['profile'] = !ctx._source['profile'];"
                 }

server/src/main/java/org/opensearch/search/pipeline/Processor.java

@@ -34,11 +34,11 @@
  */
 public interface Processor {
     /**
-     * Processor configuration key to let the factory know that the pipeline is defined in a search request.
-     * For processors whose creation is expensive (e.g. creates a connection pool), the factory can reject
-     * the request or create a more lightweight (but possibly less efficient) version of the processor.
+     * Processor configuration key to let the factory know the context for pipeline creation.
+     * <p>
+     * See {@link PipelineSource}.
      */
-    String AD_HOC_PIPELINE = "ad_hoc_pipeline";
+    String PIPELINE_SOURCE = "pipeline_source";
 
     /**
      * Gets the type of processor
@@ -144,4 +144,19 @@ public Parameters(
         }
 
     }
+
+    /**
+     * Passed via the "pipeline_source" configuration to a processor factory to convey the context for pipeline creation.
+     * <p>
+     * A processor factory may change the processor initialization behavior based on the creation context (e.g. avoiding
+     * creating expensive resources during validation or in a request-scoped pipeline.)
+     */
+    enum PipelineSource {
+        // A named pipeline is being created or updated
+        UPDATE_PIPELINE,
+        // Pipeline is defined within a search request
+        SEARCH_REQUEST,
+        // A named pipeline is being validated before being written to cluster state
+        VALIDATE_PIPELINE
+    }
 }

server/src/test/java/org/opensearch/search/pipeline/SearchPipelineServiceTests.java

@@ -49,7 +49,6 @@
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.query.TermQueryBuilder;
-import org.opensearch.ingest.ConfigurationUtils;
 import org.opensearch.plugins.SearchPipelinePlugin;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;
@@ -1093,7 +1092,7 @@ private static void assertPipelineStats(OperationStats stats, long count, long f
     public void testAdHocRejectingProcessor() {
         String processorType = "ad_hoc_rejecting";
         Map<String, Processor.Factory<SearchRequestProcessor>> requestProcessorFactories = Map.of(processorType, (pf, t, d, c) -> {
-            if (ConfigurationUtils.readBooleanProperty(processorType, t, c, Processor.AD_HOC_PIPELINE, false)) {
+            if (c.get(Processor.PIPELINE_SOURCE) == Processor.PipelineSource.SEARCH_REQUEST) {
                 throw new IllegalArgumentException(processorType + " cannot be created as part of a pipeline defined in a search request");
             }
             return new FakeRequestProcessor(processorType, t, d, r -> {});