apache-beam-examples/README.md

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# Apache Beam Examples
This project holds all the examples of apache beam that are detailed on my blog at [https://barrelsofdata.com](https://barrelsofdata.com)

## Build instructions
This is a multi-module project and uses version catalogs. The dependencies can we viewed at [/barrelsofdata/apache-beam-examples/src/branch/main/gradle/libs.versions.toml](./gradle/libs.versions.toml)

To build project, execute the following commands from the project root
- To clear all compiled classes, build and log directories
```shell script
./gradlew clean
```
- To run unit tests
```shell script
./gradlew test
```
- To run integration tests
```shell script
./gradlew integrationTest
```
- To build jar
```shell script
./gradlew build
```

## Run
Ensure you have kafka running ([kafka tutorial](https://barrelsofdata.com/apache-kafka-setup)) and a postgres sql database running.

- Create table
```sql
CREATE TABLE <TABLE_NAME> (id VARCHAR(255), ts TIMESTAMP, computed DOUBLE);
```
- Start streaming job on direct runner
```shell script
java -jar streaming/build/libs/streaming.jar \
                --runner=DirectRunner \
                --kafkaBrokers=<KAFKA_BROKER:PORT_COMMA_SEPARATED> \
                --kafkaTopic=<KAFKA_TOPIC> \
                --kafkaConsumerGroupId=<KAFKA_CONSUMER_GROUP> \
                --sqlDriver=org.postgresql.Driver \
                --jdbcUrl=jdbc:postgresql://<HOST[:PORT]>/<DATABASE> \
                --table=<TABLE_NAME> \
                --username=<USERNAME> \
                --password=<PASSWORD> \
                --resetToEarliest
```
- You can feed simulated data to the kafka topic with the key being a string (used as unique id of a sensor) and value being a json string of the following schema
```json
{"ts":<EPOCH_MILLIS>,"value":<DOUBLE_VALUE>}
```