Added support for aliases to index templates

Adapted existing PR (elastic#2739) to updated code (post elastic#4920), added tests and docs (@javanna)

Closes elastic#1825

docs/reference/indices/templates.asciidoc

@@ -27,6 +27,35 @@ Defines a template named template_1, with a template pattern of `te*`.
 The settings and mappings will be applied to any index name that matches
 the `te*` template.
 
+coming[1.1.0]
+
+It is also possible to include aliases in an index template as follows:
+
+[source,js]
+--------------------------------------------------
+curl -XPUT localhost:9200/_template/template_1 -d '
+{
+    "template" : "te*",
+    "settings" : {
+        "number_of_shards" : 1
+    },
+    "aliases" : {
+        "alias1" : {},
+        "alias2" : {
+            "filter" : {
+                "term" : {"user" : "kimchy" }
+            },
+            "routing" : "kimchy"
+        },
+        "{index}-alias" : {} <1>
+    }
+}
+'
+--------------------------------------------------
+
+<1> the `{index}` placeholder within the alias name will be replaced with the
+actual index name that the template gets applied to during index creation.
+
 [float]
 [[delete]]
 === Deleting a Template

rest-api-spec/test/indices.put_template/10_basic.yaml

@@ -15,3 +15,27 @@
 
   - match: {test.template: "test-*"}
   - match: {test.settings: {index.number_of_shards: '1', index.number_of_replicas: '0'}}
+
+---
+"Put template with aliases":
+  - do:
+      indices.put_template:
+        name: test
+        body:
+          template: test-*
+          aliases:
+            test_alias: {}
+            test_blias: {routing: b}
+            test_clias: {filter: {term :{user : kimchy}}}
+
+  - do:
+      indices.get_template:
+        name: test
+
+  - match: {test.template: "test-*"}
+  - length: {test.aliases: 3}
+  - is_true: test.aliases.test_alias
+  - match: {test.aliases.test_blias.index_routing: "b"}
+  - match: {test.aliases.test_blias.search_routing: "b"}
+  - match: {test.aliases.test_clias.filter.term.user: "kimchy"}
+

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

@@ -21,24 +21,27 @@
 import org.elasticsearch.ElasticsearchGenerationException;
 import org.elasticsearch.ElasticsearchIllegalArgumentException;
 import org.elasticsearch.ElasticsearchParseException;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
+import org.elasticsearch.action.admin.indices.alias.Alias;
 import org.elasticsearch.action.support.master.MasterNodeOperationRequest;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.collect.MapBuilder;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.xcontent.XContentBuilder;
-import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.common.xcontent.*;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 
 import java.io.IOException;
 import java.util.Map;
+import java.util.Set;
 
 import static com.google.common.collect.Maps.newHashMap;
+import static com.google.common.collect.Sets.newHashSet;
 import static org.elasticsearch.action.ValidateActions.addValidationError;
 import static org.elasticsearch.common.settings.ImmutableSettings.Builder.EMPTY_SETTINGS;
 import static org.elasticsearch.common.settings.ImmutableSettings.readSettingsFromStream;
@@ -63,6 +66,8 @@ public class PutIndexTemplateRequest extends MasterNodeOperationRequest<PutIndex
 
     private Map<String, String> mappings = newHashMap();
 
+    private final Set<Alias> aliases = newHashSet();
+
     private Map<String, IndexMetaData.Custom> customs = newHashMap();
 
     PutIndexTemplateRequest() {
@@ -251,6 +256,7 @@ public PutIndexTemplateRequest source(XContentBuilder templateBuilder) {
     /**
      * The template source definition.
      */
+    @SuppressWarnings("unchecked")
     public PutIndexTemplateRequest source(Map templateSource) {
         Map<String, Object> source = templateSource;
         for (Map.Entry<String, Object> entry : source.entrySet()) {
@@ -272,6 +278,8 @@ public PutIndexTemplateRequest source(Map templateSource) {
                     }
                     mapping(entry1.getKey(), (Map<String, Object>) entry1.getValue());
                 }
+            } else if (name.equals("aliases")) {
+                aliases((Map<String, Object>) entry.getValue());
             } else {
                 // maybe custom?
                 IndexMetaData.Custom.Factory factory = IndexMetaData.lookupFactory(name);
@@ -335,6 +343,66 @@ public PutIndexTemplateRequest custom(IndexMetaData.Custom custom) {
     Map<String, IndexMetaData.Custom> customs() {
         return this.customs;
     }
+
+    Set<Alias> aliases() {
+        return this.aliases;
+    }
+
+    /**
+     * Sets the aliases that will be associated with the index when it gets created
+     */
+    @SuppressWarnings("unchecked")
+    public PutIndexTemplateRequest aliases(Map source) {
+        try {
+            XContentBuilder builder = XContentFactory.jsonBuilder();
+            builder.map(source);
+            return aliases(builder.bytes());
+        } catch (IOException e) {
+            throw new ElasticsearchGenerationException("Failed to generate [" + source + "]", e);
+        }
+    }
+
+    /**
+     * Sets the aliases that will be associated with the index when it gets created
+     */
+    public PutIndexTemplateRequest aliases(XContentBuilder source) {
+        return aliases(source.bytes());
+    }
+
+    /**
+     * Sets the aliases that will be associated with the index when it gets created
+     */
+    public PutIndexTemplateRequest aliases(String source) {
+        return aliases(new BytesArray(source));
+    }
+
+    /**
+     * Sets the aliases that will be associated with the index when it gets created
+     */
+    public PutIndexTemplateRequest aliases(BytesReference source) {
+        try {
+            XContentParser parser = XContentHelper.createParser(source);
+            //move to the first alias
+            parser.nextToken();
+            while ((parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+                alias(Alias.fromXContent(parser));
+            }
+            return this;
+        } catch(IOException e) {
+            throw new ElasticsearchParseException("Failed to parse aliases", e);
+        }
+    }
+
+    /**
+     * Adds an alias that will be added when the index gets created.
+     *
+     * @param alias   The metadata for the new alias
+     * @return  the index template creation request
+     */
+    public PutIndexTemplateRequest alias(Alias alias) {
+        aliases.add(alias);
+        return this;
+    }
 
     @Override
     public void readFrom(StreamInput in) throws IOException {
@@ -355,6 +423,12 @@ public void readFrom(StreamInput in) throws IOException {
             IndexMetaData.Custom customIndexMetaData = IndexMetaData.lookupFactorySafe(type).readFrom(in);
             customs.put(type, customIndexMetaData);
         }
+        if (in.getVersion().onOrAfter(Version.V_1_1_0)) {
+            int aliasesSize = in.readVInt();
+            for (int i = 0; i < aliasesSize; i++) {
+                aliases.add(Alias.read(in));
+            }
+        }
     }
 
     @Override
@@ -376,5 +450,11 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeString(entry.getKey());
             IndexMetaData.lookupFactorySafe(entry.getKey()).writeTo(entry.getValue(), out);
         }
+        if (out.getVersion().onOrAfter(Version.V_1_1_0)) {
+            out.writeVInt(aliases.size());
+            for (Alias alias : aliases) {
+                alias.writeTo(out);
+            }
+        }
     }
 }

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

@@ -19,6 +19,7 @@
 package org.elasticsearch.action.admin.indices.template.put;
 
 import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.admin.indices.alias.Alias;
 import org.elasticsearch.action.support.master.MasterNodeOperationRequestBuilder;
 import org.elasticsearch.client.IndicesAdminClient;
 import org.elasticsearch.client.internal.InternalIndicesAdminClient;
@@ -109,6 +110,49 @@ public PutIndexTemplateRequestBuilder addMapping(String type, String source) {
         return this;
     }
 
+    /**
+     * Sets the aliases that will be associated with the index when it gets created
+     */
+    public PutIndexTemplateRequestBuilder setAliases(Map source) {
+        request.aliases(source);
+        return this;
+    }
+
+    /**
+     * Sets the aliases that will be associated with the index when it gets created
+     */
+    public PutIndexTemplateRequestBuilder setAliases(String source) {
+        request.aliases(source);
+        return this;
+    }
+
+    /**
+     * Sets the aliases that will be associated with the index when it gets created
+     */
+    public PutIndexTemplateRequestBuilder setAliases(XContentBuilder source) {
+        request.aliases(source);
+        return this;
+    }
+
+    /**
+     * Sets the aliases that will be associated with the index when it gets created
+     */
+    public PutIndexTemplateRequestBuilder setAliases(BytesReference source) {
+        request.aliases(source);
+        return this;
+    }
+
+    /**
+     * Adds an alias that will be added when the index template gets created.
+     *
+     * @param alias  The alias
+     * @return the request builder
+     */
+    public PutIndexTemplateRequestBuilder addAlias(Alias alias) {
+        request.alias(alias);
+        return this;
+    }
+
     /**
      * The cause for this index template creation.
      */

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

@@ -83,6 +83,7 @@ protected void masterOperation(final PutIndexTemplateRequest request, final Clus
                 .order(request.order())
                 .settings(request.settings())
                 .mappings(request.mappings())
+                .aliases(request.aliases())
                 .customs(request.customs())
                 .create(request.create())
                 .masterTimeout(request.masterNodeTimeout()),

src/main/java/org/elasticsearch/cluster/metadata/AliasMetaData.java

@@ -62,6 +62,10 @@ private AliasMetaData(String alias, CompressedString filter, String indexRouting
         }
     }
 
+    private AliasMetaData(AliasMetaData aliasMetaData, String alias) {
+        this(alias, aliasMetaData.filter(), aliasMetaData.indexRouting(), aliasMetaData.searchRouting());
+    }
+
     public String alias() {
         return alias;
     }
@@ -110,6 +114,13 @@ public static Builder newAliasMetaDataBuilder(String alias) {
         return new Builder(alias);
     }
 
+    /**
+     * Creates a new AliasMetaData instance with same content as the given one, but with a different alias name
+     */
+    public static AliasMetaData newAliasMetaData(AliasMetaData aliasMetaData, String newAlias) {
+        return new AliasMetaData(aliasMetaData, newAlias);
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
@@ -137,7 +148,7 @@ public int hashCode() {
 
     public static class Builder {
 
-        private String alias;
+        private final String alias;
 
         private CompressedString filter;