Allows multiple patterns to be specified for index templates (#21009)

* Allows for an array of index template patterns to be provided to an
index template, and rename the field from 'template' to 'index_pattern'.

Closes #20690

Author: a2lin

core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequest.java

@@ -20,6 +20,7 @@
 
 import org.elasticsearch.ElasticsearchGenerationException;
 import org.elasticsearch.ElasticsearchParseException;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.IndicesRequest;
 import org.elasticsearch.action.admin.indices.alias.Alias;
@@ -32,6 +33,8 @@
 import org.elasticsearch.common.collect.MapBuilder;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.logging.DeprecationLogger;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
@@ -41,10 +44,13 @@
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 import static org.elasticsearch.action.ValidateActions.addValidationError;
 import static org.elasticsearch.common.settings.Settings.readSettingsFromStream;
@@ -56,11 +62,15 @@
  */
 public class PutIndexTemplateRequest extends MasterNodeRequest<PutIndexTemplateRequest> implements IndicesRequest {
 
+    private static final DeprecationLogger DEPRECATION_LOGGER = new DeprecationLogger(Loggers.getLogger(PutIndexTemplateRequest.class));
+
+    public static final Version V_5_1_0 = Version.fromId(5010099);
+
     private String name;
 
     private String cause = "";
 
-    private String template;
+    private List<String> indexPatterns;
 
     private int order;
 
@@ -92,8 +102,8 @@ public ActionRequestValidationException validate() {
         if (name == null) {
             validationException = addValidationError("name is missing", validationException);
         }
-        if (template == null) {
-            validationException = addValidationError("template is missing", validationException);
+        if (indexPatterns == null || indexPatterns.size() == 0) {
+            validationException = addValidationError("pattern is missing", validationException);
         }
         return validationException;
     }
@@ -113,13 +123,13 @@ public String name() {
         return this.name;
     }
 
-    public PutIndexTemplateRequest template(String template) {
-        this.template = template;
+    public PutIndexTemplateRequest patterns(List<String> indexPatterns) {
+        this.indexPatterns = indexPatterns;
         return this;
     }
 
-    public String template() {
-        return this.template;
+    public List<String> patterns() {
+        return this.indexPatterns;
     }
 
     public PutIndexTemplateRequest order(int order) {
@@ -286,7 +296,20 @@ public PutIndexTemplateRequest source(Map templateSource) {
         for (Map.Entry<String, Object> entry : source.entrySet()) {
             String name = entry.getKey();
             if (name.equals("template")) {
-                template(entry.getValue().toString());
+                // This is needed to allow for bwc (beats, logstash) with pre-5.0 templates (#21009)
+                if(entry.getValue() instanceof String) {
+                    DEPRECATION_LOGGER.deprecated("Deprecated field [template] used, replaced by [index_patterns]");
+                    patterns(Collections.singletonList((String) entry.getValue()));
+                }
+            } else if (name.equals("index_patterns")) {
+                if(entry.getValue() instanceof String) {
+                    patterns(Collections.singletonList((String) entry.getValue()));
+                } else if (entry.getValue() instanceof List) {
+                    List<String> elements = ((List<?>) entry.getValue()).stream().map(Object::toString).collect(Collectors.toList());
+                    patterns(elements);
+                } else {
+                    throw new IllegalArgumentException("Malformed [template] value, should be a string or a list of strings");
+                }
             } else if (name.equals("order")) {
                 order(XContentMapValues.nodeIntegerValue(entry.getValue(), order()));
             } else if ("version".equals(name)) {
@@ -295,7 +318,7 @@ public PutIndexTemplateRequest source(Map templateSource) {
                 }
                 version((Integer)entry.getValue());
             } else if (name.equals("settings")) {
-                if (!(entry.getValue() instanceof Map)) {
+                if ((entry.getValue() instanceof Map) == false) {
                     throw new IllegalArgumentException("Malformed [settings] section, should include an inner object");
                 }
                 settings((Map<String, Object>) entry.getValue());
@@ -436,7 +459,7 @@ public PutIndexTemplateRequest alias(Alias alias) {
 
     @Override
     public String[] indices() {
-        return new String[]{template};
+        return indexPatterns.toArray(new String[indexPatterns.size()]);
     }
 
     @Override
@@ -449,7 +472,12 @@ public void readFrom(StreamInput in) throws IOException {
         super.readFrom(in);
         cause = in.readString();
         name = in.readString();
-        template = in.readString();
+
+        if (in.getVersion().onOrAfter(V_5_1_0)) {
+            indexPatterns = in.readList(StreamInput::readString);
+        } else {
+            indexPatterns = Collections.singletonList(in.readString());
+        }
         order = in.readInt();
         create = in.readBoolean();
         settings = readSettingsFromStream(in);
@@ -475,7 +503,11 @@ public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeString(cause);
         out.writeString(name);
-        out.writeString(template);
+        if (out.getVersion().onOrAfter(V_5_1_0)) {
+            out.writeStringList(indexPatterns);
+        } else {
+            out.writeString(indexPatterns.size() > 0 ? indexPatterns.get(0) : "");
+        }
         out.writeInt(order);
         out.writeBoolean(create);
         writeSettingsToStream(settings, out);

core/src/main/java/org/elasticsearch/action/admin/indices/template/put/PutIndexTemplateRequestBuilder.java

@@ -25,6 +25,8 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 
+import java.util.Collections;
+import java.util.List;
 import java.util.Map;
 
 public class PutIndexTemplateRequestBuilder
@@ -39,10 +41,20 @@ public PutIndexTemplateRequestBuilder(ElasticsearchClient client, PutIndexTempla
     }
 
     /**
-     * Sets the template match expression that will be used to match on indices created.
+     * Sets the match expression that will be used to match on indices created.
+     *
+     * @deprecated Replaced by {@link #setPatterns(List)}
+     */
+    @Deprecated
+    public PutIndexTemplateRequestBuilder setTemplate(String indexPattern) {
+        return setPatterns(Collections.singletonList(indexPattern));
+    }
+
+    /**
+     * Sets the match expression that will be used to match on indices created.
      */
-    public PutIndexTemplateRequestBuilder setTemplate(String template) {
-        request.template(template);
+    public PutIndexTemplateRequestBuilder setPatterns(List<String> indexPatterns) {
+        request.patterns(indexPatterns);
         return this;
     }
 

core/src/main/java/org/elasticsearch/action/admin/indices/template/put/TransportPutIndexTemplateAction.java

@@ -79,7 +79,7 @@ protected void masterOperation(final PutIndexTemplateRequest request, final Clus
         templateSettingsBuilder.put(request.settings()).normalizePrefix(IndexMetaData.INDEX_SETTING_PREFIX);
         indexScopedSettings.validate(templateSettingsBuilder);
         indexTemplateService.putTemplate(new MetaDataIndexTemplateService.PutRequest(cause, request.name())
-                .template(request.template())
+                .patterns(request.patterns())
                 .order(request.order())
                 .settings(templateSettingsBuilder.build())
                 .mappings(request.mappings())

core/src/main/java/org/elasticsearch/cluster/ClusterState.java

@@ -395,7 +395,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
                 IndexTemplateMetaData templateMetaData = cursor.value;
                 builder.startObject(templateMetaData.name());
 
-                builder.field("template", templateMetaData.template());
+                builder.field("index_patterns", templateMetaData.patterns());
                 builder.field("order", templateMetaData.order());
 
                 builder.startObject("settings");