ENH: support index template for serverless

data-prepper-plugins/opensearch/README.md

@@ -216,7 +216,7 @@ With the `document_root_key` set to `status`. The document structure would be `{
 * `region` (Optional) : The AWS region to use for credentials. Defaults to [standard SDK behavior to determine the region](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/region-selection.html).
 * `sts_role_arn` (Optional) : The STS role to assume for requests to AWS. Defaults to null, which will use the [standard SDK behavior for credentials](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/credentials.html).
 * `sts_header_overrides` (Optional): A map of header overrides to make when assuming the IAM role for the sink plugin.
-* `serverless` (Optional): A boolean flag to indicate the OpenSearch backend is Amazon OpenSearch Serverless. Default to `false`.
+* `serverless` (Optional): A boolean flag to indicate the OpenSearch backend is Amazon OpenSearch Serverless. Default to `false`. Notice that [ISM policies.](https://opensearch.org/docs/latest/im-plugin/ism/policies/) is not supported in Amazon OpenSearch Serverless and thus any ISM related configuration value has no effect, i.e. `ism_policy_file`. 
 
 ## Metrics
 ### Management Disabled Index Type

data-prepper-plugins/opensearch/src/main/java/org/opensearch/dataprepper/plugins/sink/opensearch/index/AbstractIndexManager.java

@@ -7,6 +7,7 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.common.collect.ImmutableSet;
+import org.apache.http.HttpStatus;
 import org.opensearch.client.RestHighLevelClient;
 import org.opensearch.client.opensearch.OpenSearchClient;
 import org.opensearch.client.opensearch._types.OpenSearchException;
@@ -39,6 +40,7 @@ public abstract class AbstractIndexManager implements IndexManager {
             = "Invalid alias name [%s], an index exists with the same name as the alias";
     public static final String INVALID_INDEX_ALIAS_ERROR
             = "invalid_index_name_exception";
+    static final Set<Integer> NO_ISM_HTTP_STATUS = Set.of(HttpStatus.SC_NOT_FOUND, HttpStatus.SC_BAD_REQUEST);
     private static final String TIME_PATTERN_STARTING_SYMBOLS = "%{";
     private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
     protected RestHighLevelClient restHighLevelClient;
@@ -178,9 +180,16 @@ final boolean checkISMEnabled() throws IOException {
         final GetClusterSettingsRequest request = new GetClusterSettingsRequest.Builder()
                 .includeDefaults(true)
                 .build();
-        final GetClusterSettingsResponse response = openSearchClient.cluster().getSettings(request);
-        final String enabled = getISMEnabled(response);
-        return enabled != null && enabled.equals("true");
+        try {
+            final GetClusterSettingsResponse response = openSearchClient.cluster().getSettings(request);
+            final String enabled = getISMEnabled(response);
+            return enabled != null && enabled.equals("true");
+        } catch (OpenSearchException ex) {
+            if (NO_ISM_HTTP_STATUS.contains(ex.status())) {
+                return false;
+            }
+            throw ex;
+        }
     }
 
     private String getISMEnabled(final GetClusterSettingsResponse response) {

data-prepper-plugins/opensearch/src/main/java/org/opensearch/dataprepper/plugins/sink/opensearch/index/IndexConfiguration.java

@@ -130,11 +130,6 @@ private IndexConfiguration(final Builder builder) {
         this.documentRootKey = builder.documentRootKey;
     }
 
-    private void determineTemplateType(Builder builder) {
-        this.templateType = DistributionVersion.ES6.equals(builder.distributionVersion) ? TemplateType.V1 :
-                (builder.templateType != null ? builder.templateType : TemplateType.V1);
-    }
-
     private void determineIndexType(Builder builder) {
         if(builder.indexType != null) {
             Optional<IndexType> mappedIndexType = IndexType.getByValue(builder.indexType);
@@ -148,6 +143,15 @@ private void determineIndexType(Builder builder) {
         }
     }
 
+    private void determineTemplateType(Builder builder) {
+        if (builder.serverless) {
+            templateType = TemplateType.INDEX_TEMPLATE;
+        } else {
+            templateType = DistributionVersion.ES6.equals(builder.distributionVersion) ? TemplateType.V1 :
+                    (builder.templateType != null ? builder.templateType : TemplateType.V1);
+        }
+    }
+
     public static IndexConfiguration readIndexConfig(final PluginSetting pluginSetting) {
         IndexConfiguration.Builder builder = new IndexConfiguration.Builder();
         final String indexAlias = pluginSetting.getStringOrDefault(INDEX_ALIAS, null);

data-prepper-plugins/opensearch/src/test/java/org/opensearch/dataprepper/plugins/sink/opensearch/index/DefaultIndexManagerTests.java

@@ -5,9 +5,12 @@
 
 package org.opensearch.dataprepper.plugins.sink.opensearch.index;
 
+import org.apache.http.HttpStatus;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.opensearch.client.ResponseException;
@@ -336,6 +339,21 @@ void checkISMEnabled_False() throws IOException {
         verify(openSearchClusterClient).getSettings(any(GetClusterSettingsRequest.class));
     }
 
+    @ParameterizedTest
+    @ValueSource(ints = {HttpStatus.SC_NOT_FOUND, HttpStatus.SC_BAD_REQUEST})
+    void checkISMEnabled_FalseWhenOpenSearchExceptionStatusNonRetryable(final int statusCode) throws IOException {
+        defaultIndexManager = indexManagerFactory.getIndexManager(
+                IndexType.CUSTOM, openSearchClient, restHighLevelClient, openSearchSinkConfiguration, templateStrategy);
+        when(openSearchException.status()).thenReturn(statusCode);
+        when(openSearchClusterClient.getSettings(any(GetClusterSettingsRequest.class))).thenThrow(openSearchException);
+        assertEquals(false, defaultIndexManager.checkISMEnabled());
+        verify(openSearchSinkConfiguration, times(2)).getIndexConfiguration();
+        verify(indexConfiguration).getIsmPolicyFile();
+        verify(indexConfiguration).getIndexAlias();
+        verify(openSearchClient).cluster();
+        verify(openSearchClusterClient).getSettings(any(GetClusterSettingsRequest.class));
+    }
+
     @Test
     void checkAndCreatePolicy_Normal() throws IOException {
         defaultIndexManager = indexManagerFactory.getIndexManager(

data-prepper-plugins/opensearch/src/test/java/org/opensearch/dataprepper/plugins/sink/opensearch/index/IndexConfigurationTests.java

@@ -365,6 +365,7 @@ public void testReadIndexConfig_awsOptionServerlessDefault() {
         final Map<String, Object> metadata = initializeConfigMetaData(
                 null, testIndexAlias, null, null, null, null);
         metadata.put(AWS_OPTION, Map.of(SERVERLESS, true));
+        metadata.put(TEMPLATE_TYPE, TemplateType.V1.getTypeName());
         final PluginSetting pluginSetting = getPluginSetting(metadata);
         final IndexConfiguration indexConfiguration = IndexConfiguration.readIndexConfig(pluginSetting);
         assertEquals(IndexType.MANAGEMENT_DISABLED, indexConfiguration.getIndexType());
@@ -377,10 +378,12 @@ public void testReadIndexConfig_awsServerlessIndexTypeOverride() {
         final Map<String, Object> metadata = initializeConfigMetaData(
                 IndexType.CUSTOM.getValue(), testIndexAlias, null, null, null, null);
         metadata.put(AWS_OPTION, Map.of(SERVERLESS, true));
+        metadata.put(TEMPLATE_TYPE, TemplateType.V1.getTypeName());
         final PluginSetting pluginSetting = getPluginSetting(metadata);
         final IndexConfiguration indexConfiguration = IndexConfiguration.readIndexConfig(pluginSetting);
         assertEquals(IndexType.CUSTOM, indexConfiguration.getIndexType());
         assertEquals(testIndexAlias, indexConfiguration.getIndexAlias());
+        assertEquals(TemplateType.INDEX_TEMPLATE, indexConfiguration.getTemplateType());
         assertEquals(true, indexConfiguration.getServerless());
     }