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.

How to use ?

Running via Gradle

Download the code into a $INDEXER_HOME dir.
$INDEXER_HOME/src/main/resources/config/kafka-es-indexer.properties file - update all relevant properties as explained in the comments.
$INDEXER_HOME/src/main/resources/config/logback.xml - specify directory you want to store logs in: <property name="LOG_DIR" value="/tmp"/>. Adjust values of max sizes and number of log files as needed.
$INDEXER_HOME/src/main/resources/config/kafka-es-indexer-start-options.config - consumer start options can be configured here (Start from earliest, latest, etc), more details inside a file.
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)

<bean id="messageHandler" class="org.elasticsearch.kafka.indexer.service.impl.examples.SimpleMessageHandlerImpl" scope="prototype"/>
build the app:

cd $INDEXER_HOME

./gradlew clean jar

The kafka-elasticsearch-consumer-0.0.2.0.jar will be created in the $INDEXER_HOME/build/libs/ dir.
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
run the app:

./gradlew run -Dindexer.properties=$INDEXER_HOME/src/main/resources/config/kafka-es-indexer.properties -Dlogback.configurationFile=$INDEXER_HOME/src/main/resources/config/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 export KAFKA_ELASTICSEARCH_CONSUMER_OPTS="-Dindexer.properties=$INDEXER_HOME/src/main/resources/config/kafka-es-indexer.properties -Dlogback.configurationFile=$INDEXER_HOME/src/main/resources/config/logback.xml" or modify ./kafka-elasticsearch-consumer script to include KAFKA_ELASTICSEARCH_CONSUMER_OPTS variable
run ./kafka-elasticsearch-consumer script

Versions

Kafka Version: 1.0.x
ElasticSearch: 5.5.x
JDK 1.8

Configuration

Indexer application properties are specified in the kafka-es-indexer.properties file - you have to adjust properties for your env: kafka-es-indexer.properties. You can specify you own properties file via -Dindexer.properties=/abs-path/your-kafka-es-indexer.properties

Logging properties are specified in the logback.xml file - you have to adjust properties for your env: logback.xml. You can 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

Consumer start options can be specified with system property consumer.start.option. The value of this property can be RESTART, EARLIEST, LATEST which applied for all partitions or CUSTOM which requires additional property consumer.custom.start.options.file. The value of consumer.custom.start.options.file property is an absolute path to the custom start offsets configuration file. (Look to kafka-es-indexer-custom-start-options.properties). By default RESTART option is used for all partitions.

Examples:

-Dconsumer.start.option=RESTART
-Dconsumer.start.option=LATEST
-Dconsumer.start.option=EARLIEST
-Dconsumer.start.option=CUSTOM -Dconsumer.custom.start.options.file=/abs-path/your-kafka-es-indexer-custom-start-options.properties

Customization

Indexer application 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 can 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.

Don't forget 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 elasticsearch.index.name and elasticsearch.index.type 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.

lucksak/kafka-elasticsearch-consumer