src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java - modules/index-elasticsearch - Git at Google

 // Copyright (C) 2014 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 // http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 package com.google.gerrit.elasticsearch;

 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.gson.FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES;
 import static java.nio.charset.StandardCharsets.UTF_8;

 import com.google.common.base.Preconditions;
 import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Streams;
 import com.google.common.flogger.FluentLogger;
 import com.google.common.io.BaseEncoding;
 import com.google.common.io.CharStreams;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.elasticsearch.ElasticMapping.Mapping;
 import com.google.gerrit.elasticsearch.builders.QueryBuilder;
 import com.google.gerrit.elasticsearch.builders.SearchSourceBuilder;
 import com.google.gerrit.elasticsearch.bulk.DeleteRequest;
 import com.google.gerrit.entities.converter.ProtoConverter;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.index.FieldType;
 import com.google.gerrit.index.Index;
 import com.google.gerrit.index.QueryOptions;
 import com.google.gerrit.index.Schema;
 import com.google.gerrit.index.query.DataSource;
 import com.google.gerrit.index.query.FieldBundle;
 import com.google.gerrit.index.query.HasCardinality;
 import com.google.gerrit.index.query.ListResultSet;
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.index.query.QueryParseException;
 import com.google.gerrit.index.query.ResultSet;
 import com.google.gerrit.proto.Protos;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.gerrit.server.index.IndexUtils;
 import com.google.gerrit.server.index.options.AutoFlush;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 import com.google.protobuf.MessageLite;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 import java.sql.Timestamp;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpStatus;
 import org.apache.http.StatusLine;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.entity.ContentType;
 import org.apache.http.nio.entity.NStringEntity;
 import org.apache.http.util.EntityUtils;
 import org.elasticsearch.client.Request;
 import org.elasticsearch.client.Response;

 abstract class AbstractElasticIndex<K, V> implements Index<K, V> {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();

   protected static final String BULK = "_bulk";
   protected static final String MAPPINGS = "mappings";
   protected static final String ORDER = "order";
   protected static final String DESC_SORT_ORDER = "desc";
   protected static final String ASC_SORT_ORDER = "asc";
   protected static final String UNMAPPED_TYPE = "unmapped_type";
   protected static final String SEARCH = "_search";
   protected static final String SETTINGS = "settings";

   static byte[] decodeBase64(String base64String) {
     return BaseEncoding.base64().decode(base64String);
   }

   protected static <T> List<T> decodeProtos(
       JsonObject doc, String fieldName, ProtoConverter<?, T> converter) {
     JsonArray field = doc.getAsJsonArray(fieldName);
     if (field == null) {
       return null;
     }
     return Streams.stream(field)
         .map(JsonElement::getAsString)
         .map(AbstractElasticIndex::decodeBase64)
         .map(bytes -> parseProtoFrom(bytes, converter))
         .collect(toImmutableList());
   }

   protected static <P extends MessageLite, T> T parseProtoFrom(
       byte[] bytes, ProtoConverter<P, T> converter) {
     P message = Protos.parseUnchecked(converter.getParser(), bytes);
     return converter.fromProto(message);
   }

   static String getContent(Response response) throws IOException {
     HttpEntity responseEntity = response.getEntity();
     String content = "";
     if (responseEntity != null) {
       InputStream contentStream = responseEntity.getContent();
       try (Reader reader = new InputStreamReader(contentStream, UTF_8)) {
         content = CharStreams.toString(reader);
       }
     }
     return content;
   }

   private final ElasticConfiguration config;
   private final Schema<V> schema;
   private final SitePaths sitePaths;
   private final String indexNameRaw;
   private final Map<String, String> refreshParam;

   protected final ElasticRestClientProvider client;
   protected final String indexName;
   protected final Gson gson;
   protected final ElasticQueryBuilder queryBuilder;

   AbstractElasticIndex(
       ElasticConfiguration config,
       SitePaths sitePaths,
       Schema<V> schema,
       ElasticRestClientProvider client,
       String indexName,
       AutoFlush autoFlush) {
     this.config = config;
     this.sitePaths = sitePaths;
     this.schema = schema;
     this.gson = new GsonBuilder().setFieldNamingPolicy(LOWER_CASE_WITH_UNDERSCORES).create();
     this.queryBuilder = new ElasticQueryBuilder();
     this.indexName = config.getIndexName(indexName, schema.getVersion());
     this.indexNameRaw = indexName;
     this.client = client;
     this.refreshParam =
         Map.of(
             "refresh",
             autoFlush == AutoFlush.ENABLED ? Boolean.TRUE.toString() : Boolean.FALSE.toString());
   }

   @Override
   public void insert(V obj) {
     replace(obj);
   }

   @Override
   public Schema<V> getSchema() {
     return schema;
   }

   @Override
   public void close() {
     // Do nothing. Client is closed by the provider.
   }

   @Override
   public void markReady(boolean ready) {
     IndexUtils.setReady(sitePaths, indexNameRaw, schema.getVersion(), ready);
   }

   @Override
   public void delete(K id) {
     String uri = getURI(BULK);
     Response response = postRequestWithRefreshParam(uri, getDeleteActions(id));
     int statusCode = response.getStatusLine().getStatusCode();
     if (statusCode != HttpStatus.SC_OK) {
       throw new StorageException(
           String.format("Failed to delete %s from index %s: %s", id, indexName, statusCode));
     }
   }

   @Override
   public void deleteAll() {
     // Delete the index, if it exists.
     String endpoint = indexName + client.adapter().indicesExistParams();
     Response response = performRequest("HEAD", endpoint);
     int statusCode = response.getStatusLine().getStatusCode();
     if (statusCode == HttpStatus.SC_OK) {
       response = performRequest("DELETE", indexName);
       statusCode = response.getStatusLine().getStatusCode();
       if (statusCode != HttpStatus.SC_OK) {
         throw new StorageException(
             String.format("Failed to delete index %s: %s", indexName, statusCode));
       }
     }

     // Recreate the index.
     String indexCreationFields = concatJsonString(getSettings(), getMappings());
     response = performRequest("PUT", indexName, indexCreationFields);
     statusCode = response.getStatusLine().getStatusCode();
     if (statusCode != HttpStatus.SC_OK) {
       String error = String.format("Failed to create index %s: %s", indexName, statusCode);
       throw new StorageException(error);
     }
   }

   protected abstract String getDeleteActions(K id);

   protected abstract String getMappings();

   private String getSettings() {
     return gson.toJson(ImmutableMap.of(SETTINGS, ElasticSetting.createSetting(config)));
   }

   protected abstract String getId(V v);

   protected String getMappingsForSingleType(Mapping mapping) {
     return getMappingsFor(mapping);
   }

   protected String getMappingsFor(Mapping mapping) {
     JsonObject mappings = new JsonObject();

     mappings.add(MAPPINGS, gson.toJsonTree(mapping));
     return gson.toJson(mappings);
   }

   protected String getDeleteRequest(K id) {
     return new DeleteRequest(id.toString(), indexName).toString();
   }

   protected abstract V fromDocument(JsonObject doc, Set<String> fields);

   protected FieldBundle toFieldBundle(JsonObject doc) {
     ListMultimap<String, Object> rawFields = ArrayListMultimap.create();
     for (Map.Entry<String, JsonElement> element :
         doc.get(client.adapter().rawFieldsKey()).getAsJsonObject().entrySet()) {
       checkArgument(
           getSchema().hasField(element.getKey()), "Unrecognized field " + element.getKey());
       FieldType<?> type = getSchema().getSchemaField(element.getKey()).getType();
       Iterable<JsonElement> innerItems =
           element.getValue().isJsonArray()
               ? element.getValue().getAsJsonArray()
               : Collections.singleton(element.getValue());
       for (JsonElement inner : innerItems) {
         if (type == FieldType.EXACT || type == FieldType.FULL_TEXT || type == FieldType.PREFIX) {
           rawFields.put(element.getKey(), inner.getAsString());
         } else if (type == FieldType.INTEGER || type == FieldType.INTEGER_RANGE) {
           rawFields.put(element.getKey(), inner.getAsInt());
         } else if (type == FieldType.LONG) {
           rawFields.put(element.getKey(), inner.getAsLong());
         } else if (type == FieldType.TIMESTAMP) {
           rawFields.put(element.getKey(), new Timestamp(inner.getAsLong()));
         } else if (type == FieldType.STORED_ONLY) {
           rawFields.put(element.getKey(), decodeBase64(inner.getAsString()));
         } else {
           throw FieldType.badFieldType(type);
         }
       }
     }
     return new FieldBundle(rawFields);
   }

   protected boolean hasErrors(Response response) {
     try {
       String contentType = response.getEntity().getContentType().getValue();
       Preconditions.checkState(
           contentType.equals(ContentType.APPLICATION_JSON.toString()),
           String.format("Expected %s, but was: %s", ContentType.APPLICATION_JSON, contentType));
       String responseStr = EntityUtils.toString(response.getEntity());
       JsonObject responseJson = (JsonObject) new JsonParser().parse(responseStr);
       return responseJson.get("errors").getAsBoolean();
     } catch (IOException e) {
       throw new StorageException(e);
     }
   }

   protected String toAction(String type, String id, String action) {
     JsonObject properties = new JsonObject();
     properties.addProperty("_id", id);
     properties.addProperty("_index", indexName);
     properties.addProperty("_type", type);

     JsonObject jsonAction = new JsonObject();
     jsonAction.add(action, properties);
     return jsonAction.toString() + System.lineSeparator();
   }

   protected void addNamedElement(String name, JsonObject element, JsonArray array) {
     JsonObject arrayElement = new JsonObject();
     arrayElement.add(name, element);
     array.add(arrayElement);
   }

   protected String getSearch(SearchSourceBuilder searchSource, JsonArray sortArray) {
     JsonObject search = new JsonParser().parse(searchSource.toString()).getAsJsonObject();
     search.add("sort", sortArray);
     return gson.toJson(search);
   }

   protected JsonArray getSortArray(String idFieldName) {
     JsonObject properties = new JsonObject();
     properties.addProperty(ORDER, ASC_SORT_ORDER);

     JsonArray sortArray = new JsonArray();
     addNamedElement(idFieldName, properties, sortArray);
     return sortArray;
   }

   protected String getURI(String request) {
     try {
       return URLEncoder.encode(indexName, UTF_8.toString()) + "/" + request;
     } catch (UnsupportedEncodingException e) {
       throw new StorageException(e);
     }
   }

   protected Response postRequestWithRefreshParam(String uri, Object payload) {
     return performRequest("POST", uri, payload, refreshParam);
   }

   private String concatJsonString(String target, String addition) {
     return target.substring(0, target.length() - 1) + "," + addition.substring(1);
   }

   private Response performRequest(String method, String uri) {
     return performRequest(method, uri, null);
   }

   private Response performRequest(String method, String uri, @Nullable Object payload) {
     return performRequest(method, uri, payload, Collections.emptyMap());
   }

   private Response performRequest(
       String method, String uri, @Nullable Object payload, Map<String, String> params) {
     Request request = new Request(method, uri.startsWith("/") ? uri : "/" + uri);
     if (payload != null) {
       String payloadStr = payload instanceof String ? (String) payload : payload.toString();
       request.setEntity(new NStringEntity(payloadStr, ContentType.APPLICATION_JSON));
     }
     for (Map.Entry<String, String> entry : params.entrySet()) {
       request.addParameter(entry.getKey(), entry.getValue());
     }
     try {
       return client.get().performRequest(request);
     } catch (IOException e) {
       throw new StorageException(e);
     }
   }

   protected class ElasticQuerySource implements DataSource<V> {
     private final QueryOptions opts;
     private final Predicate<V> predicate;
     private final String search;

     ElasticQuerySource(Predicate<V> p, QueryOptions opts, JsonArray sortArray)
         throws QueryParseException {
       this.opts = opts;
       this.predicate = p;
       QueryBuilder qb = queryBuilder.toQueryBuilder(p);
       SearchSourceBuilder searchSource =
           new SearchSourceBuilder(client.adapter())
               .query(qb)
               .size(opts.pageSize())
               .fields(Lists.newArrayList(opts.fields()))
               .trackTotalHits(false);
       searchSource =
           opts.searchAfter() != null
               ? searchSource.searchAfter((JsonArray) opts.searchAfter())
               : searchSource.from(opts.start());
       search = getSearch(searchSource, sortArray);
     }

     @Override
     public int getCardinality() {
       if (predicate instanceof HasCardinality) {
         return ((HasCardinality) predicate).getCardinality();
       }
       return 10;
     }

     @Override
     public ResultSet<V> read() {
       return readImpl(doc -> AbstractElasticIndex.this.fromDocument(doc, opts.fields()));
     }

     @Override
     public ResultSet<FieldBundle> readRaw() {
       return readImpl(AbstractElasticIndex.this::toFieldBundle);
     }

     private <T> ResultSet<T> readImpl(Function<JsonObject, T> mapper) {
       try {
         String uri = getURI(SEARCH);
         JsonArray searchAfter = null;
         Response response =
             performRequest(HttpPost.METHOD_NAME, uri, search, Collections.emptyMap());
         StatusLine statusLine = response.getStatusLine();
         if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
           String content = getContent(response);
           JsonObject obj =
               new JsonParser().parse(content).getAsJsonObject().getAsJsonObject("hits");
           if (obj.get("hits") != null) {
             JsonArray json = obj.getAsJsonArray("hits");
             ImmutableList.Builder<T> results = ImmutableList.builderWithExpectedSize(json.size());
             JsonObject hit = null;
             for (int i = 0; i < json.size(); i++) {
               hit = json.get(i).getAsJsonObject();
               T mapperResult = mapper.apply(hit);
               if (mapperResult != null) {
                 results.add(mapperResult);
               }
             }
             if (hit != null && hit.get("sort") != null) {
               searchAfter = hit.getAsJsonArray("sort");
             }
             JsonArray finalSearchAfter = searchAfter;
             return new ListResultSet<T>(results.build()) {
               @Override
               public Object searchAfter() {
                 return finalSearchAfter;
               }
             };
           }
         } else {
           logger.atSevere().log("%s", statusLine.getReasonPhrase());
         }
         return new ListResultSet<>(ImmutableList.of());
       } catch (IOException e) {
         throw new StorageException(e);
       }
     }
   }
 }
	// Copyright (C) 2014 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	package com.google.gerrit.elasticsearch;

	import static com.google.common.base.Preconditions.checkArgument;
	import static com.google.common.collect.ImmutableList.toImmutableList;
	import static com.google.gson.FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES;
	import static java.nio.charset.StandardCharsets.UTF_8;

	import com.google.common.base.Preconditions;
	import com.google.common.collect.ArrayListMultimap;
	import com.google.common.collect.ImmutableList;
	import com.google.common.collect.ImmutableMap;
	import com.google.common.collect.ListMultimap;
	import com.google.common.collect.Lists;
	import com.google.common.collect.Streams;
	import com.google.common.flogger.FluentLogger;
	import com.google.common.io.BaseEncoding;
	import com.google.common.io.CharStreams;
	import com.google.gerrit.common.Nullable;
	import com.google.gerrit.elasticsearch.ElasticMapping.Mapping;
	import com.google.gerrit.elasticsearch.builders.QueryBuilder;
	import com.google.gerrit.elasticsearch.builders.SearchSourceBuilder;
	import com.google.gerrit.elasticsearch.bulk.DeleteRequest;
	import com.google.gerrit.entities.converter.ProtoConverter;
	import com.google.gerrit.exceptions.StorageException;
	import com.google.gerrit.index.FieldType;
	import com.google.gerrit.index.Index;
	import com.google.gerrit.index.QueryOptions;
	import com.google.gerrit.index.Schema;
	import com.google.gerrit.index.query.DataSource;
	import com.google.gerrit.index.query.FieldBundle;
	import com.google.gerrit.index.query.HasCardinality;
	import com.google.gerrit.index.query.ListResultSet;
	import com.google.gerrit.index.query.Predicate;
	import com.google.gerrit.index.query.QueryParseException;
	import com.google.gerrit.index.query.ResultSet;
	import com.google.gerrit.proto.Protos;
	import com.google.gerrit.server.config.SitePaths;
	import com.google.gerrit.server.index.IndexUtils;
	import com.google.gerrit.server.index.options.AutoFlush;
	import com.google.gson.Gson;
	import com.google.gson.GsonBuilder;
	import com.google.gson.JsonArray;
	import com.google.gson.JsonElement;
	import com.google.gson.JsonObject;
	import com.google.gson.JsonParser;
	import com.google.protobuf.MessageLite;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.InputStreamReader;
	import java.io.Reader;
	import java.io.UnsupportedEncodingException;
	import java.net.URLEncoder;
	import java.sql.Timestamp;
	import java.util.Collections;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;
	import java.util.function.Function;
	import org.apache.http.HttpEntity;
	import org.apache.http.HttpStatus;
	import org.apache.http.StatusLine;
	import org.apache.http.client.methods.HttpPost;
	import org.apache.http.entity.ContentType;
	import org.apache.http.nio.entity.NStringEntity;
	import org.apache.http.util.EntityUtils;
	import org.elasticsearch.client.Request;
	import org.elasticsearch.client.Response;

	abstract class AbstractElasticIndex<K, V> implements Index<K, V> {
	private static final FluentLogger logger = FluentLogger.forEnclosingClass();

	protected static final String BULK = "_bulk";
	protected static final String MAPPINGS = "mappings";
	protected static final String ORDER = "order";
	protected static final String DESC_SORT_ORDER = "desc";
	protected static final String ASC_SORT_ORDER = "asc";
	protected static final String UNMAPPED_TYPE = "unmapped_type";
	protected static final String SEARCH = "_search";
	protected static final String SETTINGS = "settings";

	static byte[] decodeBase64(String base64String) {
	return BaseEncoding.base64().decode(base64String);
	}

	protected static <T> List<T> decodeProtos(
	JsonObject doc, String fieldName, ProtoConverter<?, T> converter) {
	JsonArray field = doc.getAsJsonArray(fieldName);
	if (field == null) {
	return null;
	}
	return Streams.stream(field)
	.map(JsonElement::getAsString)
	.map(AbstractElasticIndex::decodeBase64)
	.map(bytes -> parseProtoFrom(bytes, converter))
	.collect(toImmutableList());
	}

	protected static <P extends MessageLite, T> T parseProtoFrom(
	byte[] bytes, ProtoConverter<P, T> converter) {
	P message = Protos.parseUnchecked(converter.getParser(), bytes);
	return converter.fromProto(message);
	}

	static String getContent(Response response) throws IOException {
	HttpEntity responseEntity = response.getEntity();
	String content = "";
	if (responseEntity != null) {
	InputStream contentStream = responseEntity.getContent();
	try (Reader reader = new InputStreamReader(contentStream, UTF_8)) {
	content = CharStreams.toString(reader);
	}
	}
	return content;
	}

	private final ElasticConfiguration config;
	private final Schema<V> schema;
	private final SitePaths sitePaths;
	private final String indexNameRaw;
	private final Map<String, String> refreshParam;

	protected final ElasticRestClientProvider client;
	protected final String indexName;
	protected final Gson gson;
	protected final ElasticQueryBuilder queryBuilder;

	AbstractElasticIndex(
	ElasticConfiguration config,
	SitePaths sitePaths,
	Schema<V> schema,
	ElasticRestClientProvider client,
	String indexName,
	AutoFlush autoFlush) {
	this.config = config;
	this.sitePaths = sitePaths;
	this.schema = schema;
	this.gson = new GsonBuilder().setFieldNamingPolicy(LOWER_CASE_WITH_UNDERSCORES).create();
	this.queryBuilder = new ElasticQueryBuilder();
	this.indexName = config.getIndexName(indexName, schema.getVersion());
	this.indexNameRaw = indexName;
	this.client = client;
	this.refreshParam =
	Map.of(
	"refresh",
	autoFlush == AutoFlush.ENABLED ? Boolean.TRUE.toString() : Boolean.FALSE.toString());
	}

	@Override
	public void insert(V obj) {
	replace(obj);
	}

	@Override
	public Schema<V> getSchema() {
	return schema;
	}

	@Override
	public void close() {
	// Do nothing. Client is closed by the provider.
	}

	@Override
	public void markReady(boolean ready) {
	IndexUtils.setReady(sitePaths, indexNameRaw, schema.getVersion(), ready);
	}

	@Override
	public void delete(K id) {
	String uri = getURI(BULK);
	Response response = postRequestWithRefreshParam(uri, getDeleteActions(id));
	int statusCode = response.getStatusLine().getStatusCode();
	if (statusCode != HttpStatus.SC_OK) {
	throw new StorageException(
	String.format("Failed to delete %s from index %s: %s", id, indexName, statusCode));
	}
	}

	@Override
	public void deleteAll() {
	// Delete the index, if it exists.
	String endpoint = indexName + client.adapter().indicesExistParams();
	Response response = performRequest("HEAD", endpoint);
	int statusCode = response.getStatusLine().getStatusCode();
	if (statusCode == HttpStatus.SC_OK) {
	response = performRequest("DELETE", indexName);
	statusCode = response.getStatusLine().getStatusCode();
	if (statusCode != HttpStatus.SC_OK) {
	throw new StorageException(
	String.format("Failed to delete index %s: %s", indexName, statusCode));
	}
	}

	// Recreate the index.
	String indexCreationFields = concatJsonString(getSettings(), getMappings());
	response = performRequest("PUT", indexName, indexCreationFields);
	statusCode = response.getStatusLine().getStatusCode();
	if (statusCode != HttpStatus.SC_OK) {
	String error = String.format("Failed to create index %s: %s", indexName, statusCode);
	throw new StorageException(error);
	}
	}

	protected abstract String getDeleteActions(K id);

	protected abstract String getMappings();

	private String getSettings() {
	return gson.toJson(ImmutableMap.of(SETTINGS, ElasticSetting.createSetting(config)));
	}

	protected abstract String getId(V v);

	protected String getMappingsForSingleType(Mapping mapping) {
	return getMappingsFor(mapping);
	}

	protected String getMappingsFor(Mapping mapping) {
	JsonObject mappings = new JsonObject();

	mappings.add(MAPPINGS, gson.toJsonTree(mapping));
	return gson.toJson(mappings);
	}

	protected String getDeleteRequest(K id) {
	return new DeleteRequest(id.toString(), indexName).toString();
	}

	protected abstract V fromDocument(JsonObject doc, Set<String> fields);

	protected FieldBundle toFieldBundle(JsonObject doc) {
	ListMultimap<String, Object> rawFields = ArrayListMultimap.create();
	for (Map.Entry<String, JsonElement> element :
	doc.get(client.adapter().rawFieldsKey()).getAsJsonObject().entrySet()) {
	checkArgument(
	getSchema().hasField(element.getKey()), "Unrecognized field " + element.getKey());
	FieldType<?> type = getSchema().getSchemaField(element.getKey()).getType();
	Iterable<JsonElement> innerItems =
	element.getValue().isJsonArray()
	? element.getValue().getAsJsonArray()
	: Collections.singleton(element.getValue());
	for (JsonElement inner : innerItems) {
	if (type == FieldType.EXACT \|\| type == FieldType.FULL_TEXT \|\| type == FieldType.PREFIX) {
	rawFields.put(element.getKey(), inner.getAsString());
	} else if (type == FieldType.INTEGER \|\| type == FieldType.INTEGER_RANGE) {
	rawFields.put(element.getKey(), inner.getAsInt());
	} else if (type == FieldType.LONG) {
	rawFields.put(element.getKey(), inner.getAsLong());
	} else if (type == FieldType.TIMESTAMP) {
	rawFields.put(element.getKey(), new Timestamp(inner.getAsLong()));
	} else if (type == FieldType.STORED_ONLY) {
	rawFields.put(element.getKey(), decodeBase64(inner.getAsString()));
	} else {
	throw FieldType.badFieldType(type);
	}
	}
	}
	return new FieldBundle(rawFields);
	}

	protected boolean hasErrors(Response response) {
	try {
	String contentType = response.getEntity().getContentType().getValue();
	Preconditions.checkState(
	contentType.equals(ContentType.APPLICATION_JSON.toString()),
	String.format("Expected %s, but was: %s", ContentType.APPLICATION_JSON, contentType));
	String responseStr = EntityUtils.toString(response.getEntity());
	JsonObject responseJson = (JsonObject) new JsonParser().parse(responseStr);
	return responseJson.get("errors").getAsBoolean();
	} catch (IOException e) {
	throw new StorageException(e);
	}
	}

	protected String toAction(String type, String id, String action) {
	JsonObject properties = new JsonObject();
	properties.addProperty("_id", id);
	properties.addProperty("_index", indexName);
	properties.addProperty("_type", type);

	JsonObject jsonAction = new JsonObject();
	jsonAction.add(action, properties);
	return jsonAction.toString() + System.lineSeparator();
	}

	protected void addNamedElement(String name, JsonObject element, JsonArray array) {
	JsonObject arrayElement = new JsonObject();
	arrayElement.add(name, element);
	array.add(arrayElement);
	}

	protected String getSearch(SearchSourceBuilder searchSource, JsonArray sortArray) {
	JsonObject search = new JsonParser().parse(searchSource.toString()).getAsJsonObject();
	search.add("sort", sortArray);
	return gson.toJson(search);
	}

	protected JsonArray getSortArray(String idFieldName) {
	JsonObject properties = new JsonObject();
	properties.addProperty(ORDER, ASC_SORT_ORDER);

	JsonArray sortArray = new JsonArray();
	addNamedElement(idFieldName, properties, sortArray);
	return sortArray;
	}

	protected String getURI(String request) {
	try {
	return URLEncoder.encode(indexName, UTF_8.toString()) + "/" + request;
	} catch (UnsupportedEncodingException e) {
	throw new StorageException(e);
	}
	}

	protected Response postRequestWithRefreshParam(String uri, Object payload) {
	return performRequest("POST", uri, payload, refreshParam);
	}

	private String concatJsonString(String target, String addition) {
	return target.substring(0, target.length() - 1) + "," + addition.substring(1);
	}

	private Response performRequest(String method, String uri) {
	return performRequest(method, uri, null);
	}

	private Response performRequest(String method, String uri, @Nullable Object payload) {
	return performRequest(method, uri, payload, Collections.emptyMap());
	}

	private Response performRequest(
	String method, String uri, @Nullable Object payload, Map<String, String> params) {
	Request request = new Request(method, uri.startsWith("/") ? uri : "/" + uri);
	if (payload != null) {
	String payloadStr = payload instanceof String ? (String) payload : payload.toString();
	request.setEntity(new NStringEntity(payloadStr, ContentType.APPLICATION_JSON));
	}
	for (Map.Entry<String, String> entry : params.entrySet()) {
	request.addParameter(entry.getKey(), entry.getValue());
	}
	try {
	return client.get().performRequest(request);
	} catch (IOException e) {
	throw new StorageException(e);
	}
	}

	protected class ElasticQuerySource implements DataSource<V> {
	private final QueryOptions opts;
	private final Predicate<V> predicate;
	private final String search;

	ElasticQuerySource(Predicate<V> p, QueryOptions opts, JsonArray sortArray)
	throws QueryParseException {
	this.opts = opts;
	this.predicate = p;
	QueryBuilder qb = queryBuilder.toQueryBuilder(p);
	SearchSourceBuilder searchSource =
	new SearchSourceBuilder(client.adapter())
	.query(qb)
	.size(opts.pageSize())
	.fields(Lists.newArrayList(opts.fields()))
	.trackTotalHits(false);
	searchSource =
	opts.searchAfter() != null
	? searchSource.searchAfter((JsonArray) opts.searchAfter())
	: searchSource.from(opts.start());
	search = getSearch(searchSource, sortArray);
	}

	@Override
	public int getCardinality() {
	if (predicate instanceof HasCardinality) {
	return ((HasCardinality) predicate).getCardinality();
	}
	return 10;
	}

	@Override
	public ResultSet<V> read() {
	return readImpl(doc -> AbstractElasticIndex.this.fromDocument(doc, opts.fields()));
	}

	@Override
	public ResultSet<FieldBundle> readRaw() {
	return readImpl(AbstractElasticIndex.this::toFieldBundle);
	}

	private <T> ResultSet<T> readImpl(Function<JsonObject, T> mapper) {
	try {
	String uri = getURI(SEARCH);
	JsonArray searchAfter = null;
	Response response =
	performRequest(HttpPost.METHOD_NAME, uri, search, Collections.emptyMap());
	StatusLine statusLine = response.getStatusLine();
	if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
	String content = getContent(response);
	JsonObject obj =
	new JsonParser().parse(content).getAsJsonObject().getAsJsonObject("hits");
	if (obj.get("hits") != null) {
	JsonArray json = obj.getAsJsonArray("hits");
	ImmutableList.Builder<T> results = ImmutableList.builderWithExpectedSize(json.size());
	JsonObject hit = null;
	for (int i = 0; i < json.size(); i++) {
	hit = json.get(i).getAsJsonObject();
	T mapperResult = mapper.apply(hit);
	if (mapperResult != null) {
	results.add(mapperResult);
	}
	}
	if (hit != null && hit.get("sort") != null) {
	searchAfter = hit.getAsJsonArray("sort");
	}
	JsonArray finalSearchAfter = searchAfter;
	return new ListResultSet<T>(results.build()) {
	@Override
	public Object searchAfter() {
	return finalSearchAfter;
	}
	};
	}
	} else {
	logger.atSevere().log("%s", statusLine.getReasonPhrase());
	}
	return new ListResultSet<>(ImmutableList.of());
	} catch (IOException e) {
	throw new StorageException(e);
	}
	}
	}
	}