Welcome to the kafka-elasticsearch-standalone-consumer wiki!

Architecture of the kafka-elasticsearch-standalone-consumer [indexer]

Introduction

Kafka Standalone Consumer [Indexer] will read messages from Kafka, in batches, process and bulk-index them into ElasticSearch.

As described in the illustration above, here is how the indexer works:

• Lets assume Kafka has a topic Topic1 with 5 partitions

• In the configuration file, kafka-es-indexer.properties, set firstPartition=0 and lastPartition=4 properties

• start the indexer application as described below

• there will be 5 threads started, one for each consumer for each of the partitions

• each job will be reading events from Kafka and indexing them (in batches) into ElasticSearch - using configured index name and type

• when a new partition is added to the kafka topic - configuration has to be updated and the indexer application has to be restarted

How to use ?

Running via Gradle

1. Download the code into a $INDEXER_HOME dir.

2. cp $INDEXER_HOME/src/main/resources/config/kafka-es-indexer.properties /your/absolute/path/kafka-es-indexer.properties.template file - update all relevant properties as explained in the comments

3. cp $INDEXER_HOME/src/main/resources/config/logback.xml.template /your/absolute/path/logback.xml

specify directory you want to store logs in:

adjust values of max sizes and number of log files as needed

4. modify $INDEXER_HOME`/src/main/resources/spring/kafka-es-context-public.xml if needed

   If you want to use custom IMessageHandler class - specify it in the following config: (make sure to only modify the class name, not the beans' name/scope)

5. build the app:

cd $INDEXER_HOME ./gradlew clean jar

The kafka-es-indexer-2.0.jar will be created in the $INDEXER_HOME/build/libs/ dir.

6. make sure your $JAVA_HOME env variable is set (use JDK1.8 or above); you may want to adjust JVM options and other values in the gradlew script and gradle.properties file

7. run the app:

   ./gradlew run -Dindexer.properties=/your/absolute/path/kafka-es-indexer.properties -Dlogback.configurationFile=/your/absolute/path/logback.xml

Running via generated scripts:

• Steps 1 - 6 are the same

• run: ./gradlew clean installDist

• cd ../build/install/kafka-elasticsearch-consumer/bin dir:

• run ./kafka-elasticsearch-consumer -Dindexer.properties=/your/absolute/path/kafka-es-indexer.properties -Dlogback.configurationFile=/your/absolute/path/logback.xml script

Running via provided run_indexer.sh script:

• Steps 1 - 6 are the same

• run: './gradlew clean installDist' - this will create a folder $INDEXER_HOME/build/install/kafka-elasticsearch-consumer/lib with all dependencies and the application jar (kafka-elasticsearch-consumer-0.0.2.0.jar)

• update (or create a copy of) the run_indexer.sh script - update all paths

• run ./run_indexer.sh script

Versions

• Kafka Version: 0.8.2.1

• ElasticSearch: 2.x

• Scala Version for Kafka Build: 2.10.0

• JDK 1.8

Configuration

Indexer application properties are specified in the kafka_es_indexer.properties.template file - you have to create your own copy of this file and adjust properties for your env: kafka-es-indexer.properties.template Example of customized properties: kafka-es-indexer-local.properties You specify your own properties file via -Dindexer.properties=/abs-path/your.properties property

Logging properties are specified in the logback.xml.template file - you have to create your own copy of this file and adjust properties for your env: logback.xml.template Example logback-test.xml is here: logback-test.xml You specify your own logback config file via -Dlogback.configurationFile=/abs-path/your-logback.xml property

Indexer application Spring configuration is specified in the kafka-es-context-public.xml: kafka-es-context.xml

Customization

Indexer applicatin can be easily customized. The main areas for customizations are:

• message handling/conversion examples of use cases for this customization: -- your incoming messages are not in a JSON format compatible with the expected ES message formats -- your messages have to be enreached with data from other sources (via other meta-data lookups, etc.) -- you want to selectively index messages into ES based on some custom criteria
• index name/type customization

ES message handling customization

Message handling can be customized by implementing the IMessageHandler interface :

• org.elasticsearch.kafka.indexer.service.IMessageHandler is an interface that defines main methods for reading events from Kafka, processing them, and bulk-intexing into ElasticSearch. One can implement all or some of the methods if custom behavior is needed. You can customize:
• transformMessage(...) method to transform an event from one format into another;
• addEventToBatch(...) method - adding an event to specified (or custom ) index, with or without routing info
• postToElasticSearch(...) method - most likely you won't need to customize this

To do this customization, you implement the IMessageHandler interface and inject the ElasticSearchBatchService into your implementation class and delegate most of the methods to the ElasticSearchBatchService class. ElasticSearchBatchService gives you basic batching operations.

See org.elasticsearch.kafka.indexer.service.impl.examples.SimpleMessageHandlerImpl for an example of such customization.

• Do remember to specify your custom message handler class in the kafka-es-context-public.xml file. By default, SimpleMessageHandlerImpl will be used

ES index name/type management customization

Index name and index type management/determination customization can be done by providing custom logic in your implementation of the IMessageHandler interface:

• org.elasticsearch.kafka.indexer.service.impl.examples.SimpleMessageHandlerImpl uses indexName and indexType values as configured in the kafka-es-indexer.properties file. If you want to use custom logic - add it to the addEventToBatch(...) method

Running as a Docker Container

TODO

License

kafka-elasticsearch-standalone-consumer

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.

Contributors

• Krishna Raj
• Marina Popova
• Dhyan Muralidharan
• Andriy Pyshchyk