/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.client.sniff;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.elasticsearch.client.Response;
import org.elasticsearch.client.RestClient;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.TimeUnit;
/**
* Class responsible for sniffing the http hosts from elasticsearch through the nodes info api and returning them back.
* Compatible with elasticsearch 5.x and 2.x.
*/
public final class ElasticsearchHostsSniffer implements HostsSniffer {
private static final Log logger = LogFactory.getLog(ElasticsearchHostsSniffer.class);
public static final long DEFAULT_SNIFF_REQUEST_TIMEOUT = TimeUnit.SECONDS.toMillis(1);
private final RestClient restClient;
private final Map<String, String> sniffRequestParams;
private final Scheme scheme;
private final JsonFactory jsonFactory = new JsonFactory();
/**
* Creates a new instance of the Elasticsearch sniffer. It will use the provided {@link RestClient} to fetch the hosts,
* through the nodes info api, the default sniff request timeout value {@link #DEFAULT_SNIFF_REQUEST_TIMEOUT} and http
* as the scheme for all the hosts.
* @param restClient client used to fetch the hosts from elasticsearch through nodes info api. Usually the same instance
* that is also provided to {@link Sniffer#builder(RestClient)}, so that the hosts are set to the same
* client that was used to fetch them.
*/
public ElasticsearchHostsSniffer(RestClient restClient) {
this(restClient, DEFAULT_SNIFF_REQUEST_TIMEOUT, ElasticsearchHostsSniffer.Scheme.HTTP);
}
/**
* Creates a new instance of the Elasticsearch sniffer. It will use the provided {@link RestClient} to fetch the hosts
* through the nodes info api, the provided sniff request timeout value and scheme.
* @param restClient client used to fetch the hosts from elasticsearch through nodes info api. Usually the same instance
* that is also provided to {@link Sniffer#builder(RestClient)}, so that the hosts are set to the same
* client that was used to sniff them.
* @param sniffRequestTimeoutMillis the sniff request timeout (in milliseconds) to be passed in as a query string parameter
* to elasticsearch. Allows to halt the request without any failure, as only the nodes
* that have responded within this timeout will be returned.
* @param scheme the scheme to associate sniffed nodes with (as it is not returned by elasticsearch)
*/
public ElasticsearchHostsSniffer(RestClient restClient, long sniffRequestTimeoutMillis, Scheme scheme) {
this.restClient = Objects.requireNonNull(restClient, "restClient cannot be null");
if (sniffRequestTimeoutMillis < 0) {
throw new IllegalArgumentException("sniffRequestTimeoutMillis must be greater than 0");
}
this.sniffRequestParams = Collections.<String, String>singletonMap("timeout", sniffRequestTimeoutMillis + "ms");
this.scheme = Objects.requireNonNull(scheme, "scheme cannot be null");
}
/**
* Calls the elasticsearch nodes info api, parses the response and returns all the found http hosts
*/
public List<HttpHost> sniffHosts() throws IOException {
Response response = restClient.performRequest("get", "/_nodes/http", sniffRequestParams);
return readHosts(response.getEntity());
}
private List<HttpHost> readHosts(HttpEntity entity) throws IOException {
try (InputStream inputStream = entity.getContent()) {
JsonParser parser = jsonFactory.createParser(inputStream);
if (parser.nextToken() != JsonToken.START_OBJECT) {
throw new IOException("expected data to start with an object");
}
List<HttpHost> hosts = new ArrayList<>();
while (parser.nextToken() != JsonToken.END_OBJECT) {
if (parser.getCurrentToken() == JsonToken.START_OBJECT) {
if ("nodes".equals(parser.getCurrentName())) {
while (parser.nextToken() != JsonToken.END_OBJECT) {
JsonToken token = parser.nextToken();
assert token == JsonToken.START_OBJECT;
String nodeId = parser.getCurrentName();
HttpHost sniffedHost = readHost(nodeId, parser, this.scheme);
if (sniffedHost != null) {
logger.trace("adding node [" + nodeId + "]");
hosts.add(sniffedHost);
}
}
} else {
parser.skipChildren();
}
}
}
return hosts;
}
}
private static HttpHost readHost(String nodeId, JsonParser parser, Scheme scheme) throws IOException {
HttpHost httpHost = null;
String fieldName = null;
while (parser.nextToken() != JsonToken.END_OBJECT) {
if (parser.getCurrentToken() == JsonToken.FIELD_NAME) {
fieldName = parser.getCurrentName();
} else if (parser.getCurrentToken() == JsonToken.START_OBJECT) {
if ("http".equals(fieldName)) {
while (parser.nextToken() != JsonToken.END_OBJECT) {
if (parser.getCurrentToken() == JsonToken.VALUE_STRING && "publish_address".equals(parser.getCurrentName())) {
URI boundAddressAsURI = URI.create(scheme + "://" + parser.getValueAsString());
httpHost = new HttpHost(boundAddressAsURI.getHost(), boundAddressAsURI.getPort(),
boundAddressAsURI.getScheme());
} else if (parser.getCurrentToken() == JsonToken.START_OBJECT) {
parser.skipChildren();
}
}
} else {
parser.skipChildren();
}
}
}
//http section is not present if http is not enabled on the node, ignore such nodes
if (httpHost == null) {
logger.debug("skipping node [" + nodeId + "] with http disabled");
return null;
}
return httpHost;
}
public enum Scheme {
HTTP("http"), HTTPS("https");
private final String name;
Scheme(String name) {
this.name = name;
}
@Override
public String toString() {
return name;
}
}
}