115 lines
5.4 KiB
Text
115 lines
5.4 KiB
Text
# Elasticsearch Clients
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image:https://api.travis-ci.org/xbib/content.svg[title="Build status", link="https://travis-ci.org/jprante/elasticsearch-extras-client/"]
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image:https://img.shields.io/sonar/http/nemo.sonarqube.com/org.xbib%3Aelasticsearch-extras-client/coverage.svg?style=flat-square[title="Coverage", link="https://sonarqube.com/dashboard/index?id=org.xbib%3Aelasticsearch-extras-client"]
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image:https://maven-badges.herokuapp.com/maven-central/org.xbib/elasticsearch-extras-client/badge.svg[title="Maven Central", link="http://search.maven.org/#search%7Cga%7C1%7Cxbib%20elasticsearch-extras-client"]
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image:https://img.shields.io/badge/License-Apache%202.0-blue.svg[title="Apache License 2.0", link="https://opensource.org/licenses/Apache-2.0"]
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This Java library extends the Elasticsearch Java Client classes for better convenience.
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It is not a plugin for Elasticsearch. Use it by importing the jar from Maven Central into your project.
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The Elasticsearch node client and transport client APIs are unified in a `ClientMethods` interface. This interface uses
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bulk services and index management under the hood, like index creation, alias managent, and retention policies.
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Two classes `BulkNodeClient` and `BulkTransportClient` combine the client methods with the `BulkProcessor`,
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provide some logging convenience, and still offer the `Client` interface of Elasticsearch by using the `client()` method.
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A `MockTransportClient` implements the `BulkTransportClient` API but does not need a running Elasticsearch node
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to connect to. This is useful for unit testing.
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The client classes are enriched by metrics that can measure document count, size, and speed.
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A `ClientBuilder` helps to build client instances. For example
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[source,java]
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----
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ClientBuilder clientBuilder = ClientBuilder.builder()
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.put(elasticsearchSettings)
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.put("client.transport.ping_timeout", settings.get("timeout", "30s"))
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.put(ClientBuilder.MAX_ACTIONS_PER_REQUEST, settings.getAsInt("maxbulkactions", 1000))
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.put(ClientBuilder.MAX_CONCURRENT_REQUESTS, settings.getAsInt("maxconcurrentbulkrequests",
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Runtime.getRuntime().availableProcessors()))
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.setMetric(new SimpleBulkMetric())
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.setControl(new SimpleBulkControl());
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BulkTransportClient client = clientBuilder.toBulkTransportClient();
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----
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For more examples, consult the integration etsts at `src/integration-test/java`.
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A re-implemented `BulkProcessor` allows flushing of documents before closing.
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Also, a light-weight re-implementation of the `TransportClient` class is provided with the following differences to the original `TransportClient`:
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- no retry mechanism, no exponential back off, if an error or exception is encountered, the client fails fast
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- no _sniffing_, that means, no additional nodes are detected during runtime
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- methods of `TransportClient`, `TransportClientNodesServce`, `TransportClientProxy` classes are merged into one class
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- configurable ping timeout
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#### Some interesting methods
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Here are some methods from the `ClientMethods` API, these are not all methods, but maybe
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some of which can demonstrate the convenience.
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Create new index, use settings and mappings from input streams.
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----
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ClientMethods newIndex(String index, String type, InputStream settings, InputStream mappings) throws IOException
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----
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Switch an index to bulk mode - disable replicas, set refresh interval.
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----
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ClientMethods startBulk(String index, long startRefreshIntervalSeconds, long stopRefreshIntervalSeconds) throws IOException
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----
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Index document, use bulk mode automatically.
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----
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ClientMethods index(String index, String type, String id, String source);
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----
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Wait for outstanding bulk responsed from the cluster.
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----
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ClientMethods waitForResponses(TimeValue maxWait) throws InterruptedException, ExecutionException;
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----
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Update replica level on an index.
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----
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int updateReplicaLevel(String index, int level) throws IOException;
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----
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Switch aliases from a previously created index with a timestamp to a current index under the common base name `index`.
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----
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void switchAliases(String index, String concreteIndex, List<String> extraAliases, IndexAliasAdder adder);
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----
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Retention policy for an index. All indices before `timestampdiff` should be deleted,
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but `mintokeep` indices must be kept.
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----
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void performRetentionPolicy(String index, String concreteIndex, int timestampdiff, int mintokeep);
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----
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## Prerequisites
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You will need Java 8, although Elasticsearch 2.x requires Java 7. Java 7 is not supported.
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## Dependencies
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This project depends only on https://github.com/xbib/metrics which is a slim version of Coda Hale's metrics library,
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and Elasticsearch.
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## How to decode the Elasticsearch version
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This project uses semantic versioning to determine the Elasticsearch upstream version it is built against.
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The first three version numbers are the corresponding Elasticsearch version. The last version number is
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an incrementing number, the version of this project.
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Please use exactly the Elasticsearch version which is declared in the project's version.
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Other Elasticsearch versions do not work and will never work, it is not worth to try it.
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This is by design of the Elasticsearch project because the internal node communication protocol depends on the
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exact same API implementation. Also, the exact same version of Java virtual machine is remoonded on server
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and client side.
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