Add a cluster deprecation check for index templates containing multiple types (#72540)

Using an index template that creates multiple mapping types will already
throw an error in 7.x. This upgrade check should help filter out any unused
templates with multiple types that are still lurking in the cluster state.

Author: romseygeek

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/ClusterDeprecationChecks.java

@@ -12,6 +12,8 @@
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.MappingMetadata;
 import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.collect.ImmutableOpenMap;
+import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.index.IndexSettings;
@@ -167,4 +169,24 @@ static DeprecationIssue checkPollIntervalTooLow(ClusterState state) {
         }
         return null;
     }
+
+    static DeprecationIssue checkTemplatesWithMultipleTypes(ClusterState state) {
+        Set<String> templatesWithMultipleTypes = new HashSet<>();
+        state.getMetadata().getTemplates().forEach((templateCursor) -> {
+            String templateName = templateCursor.key;
+            ImmutableOpenMap<String, CompressedXContent> mappings = templateCursor.value.mappings();
+            if (mappings != null && mappings.size() > 1) {
+                templatesWithMultipleTypes.add(templateName);
+            }
+        });
+        if (templatesWithMultipleTypes.isEmpty()) {
+            return null;
+        }
+        return new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
+            "Some index templates contain multiple mapping types",
+            "https://www.elastic.co/guide/en/elasticsearch/reference/master/removal-of-types.html",
+            "Index templates " + templatesWithMultipleTypes
+            + " define multiple types and so will cause errors when used in index creation"
+            );
+    }
 }

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/DeprecationChecks.java

@@ -38,7 +38,8 @@ private DeprecationChecks() {
             ClusterDeprecationChecks::checkUserAgentPipelines,
             ClusterDeprecationChecks::checkTemplatesWithTooManyFields,
             ClusterDeprecationChecks::checkPollIntervalTooLow,
-            ClusterDeprecationChecks::checkTemplatesWithFieldNamesDisabled
+            ClusterDeprecationChecks::checkTemplatesWithFieldNamesDisabled,
+            ClusterDeprecationChecks::checkTemplatesWithMultipleTypes
         ));
 
 

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/ClusterDeprecationChecksTests.java

@@ -13,6 +13,7 @@
 import org.elasticsearch.cluster.metadata.Metadata;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentType;
@@ -21,7 +22,6 @@
 import org.elasticsearch.ingest.IngestService;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.xpack.core.deprecation.DeprecationIssue;
-import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -32,6 +32,8 @@
 import static org.elasticsearch.xpack.core.ilm.LifecycleSettings.LIFECYCLE_POLL_INTERVAL_SETTING;
 import static org.elasticsearch.xpack.deprecation.DeprecationChecks.CLUSTER_SETTINGS_CHECKS;
 import static org.elasticsearch.xpack.deprecation.IndexDeprecationChecksTests.addRandomFields;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasSize;
 
 public class ClusterDeprecationChecksTests extends ESTestCase {
 
@@ -272,7 +274,41 @@ public void testPollIntervalTooLow() {
                 .metadata(okMetadata)
                 .build();
             List<DeprecationIssue> noIssues = DeprecationChecks.filterChecks(CLUSTER_SETTINGS_CHECKS, c -> c.apply(okState));
-            assertThat(noIssues, Matchers.hasSize(0));
+            assertThat(noIssues, hasSize(0));
         }
     }
+
+    public void testIndexTemplatesWithMultipleTypes() throws IOException {
+
+        IndexTemplateMetadata multipleTypes = IndexTemplateMetadata.builder("multiple-types")
+            .patterns(Collections.singletonList("foo"))
+            .putMapping("type1", "{\"type1\":{}}")
+            .putMapping("type2", "{\"type2\":{}}")
+            .build();
+        IndexTemplateMetadata singleType = IndexTemplateMetadata.builder("single-type")
+            .patterns(Collections.singletonList("foo"))
+            .putMapping("type1", "{\"type1\":{}}")
+            .build();
+        ImmutableOpenMap<String, IndexTemplateMetadata> templates = ImmutableOpenMap.<String, IndexTemplateMetadata>builder()
+            .fPut("multiple-types", multipleTypes)
+            .fPut("single-type", singleType)
+            .build();
+        Metadata badMetadata = Metadata.builder()
+            .templates(templates)
+            .build();
+        ClusterState badState = ClusterState.builder(new ClusterName("test")).metadata(badMetadata).build();
+        List<DeprecationIssue> issues = DeprecationChecks.filterChecks(CLUSTER_SETTINGS_CHECKS, c -> c.apply(badState));
+        assertThat(issues, hasSize(1));
+        assertThat(issues.get(0).getDetails(),
+            equalTo("Index templates [multiple-types] define multiple types and so will cause errors when used in index creation"));
+
+        Metadata goodMetadata = Metadata.builder()
+            .templates(ImmutableOpenMap.<String, IndexTemplateMetadata>builder().fPut("single-type", singleType).build())
+            .build();
+        ClusterState goodState = ClusterState.builder(new ClusterName("test")).metadata(goodMetadata).build();
+        assertThat(
+            DeprecationChecks.filterChecks(CLUSTER_SETTINGS_CHECKS, c -> c.apply(goodState)),
+            hasSize(0)
+        );
+    }
 }