Can someone post an example or help how i can use KafkaItemWriter to write java objects into non-default topic. Just like in SpringKafka we use KafkaTemplate.send(topicName, user) is there a way for kafkaItemWriter also? I do not want to write to default topic configured through properites file like spring.kafka.template.default-topic=topicName.
In my springBatch job i want to run to different batch jobs and like to write into two different topics.
I’m not sure this is what you want or not.
But KafkaTemplate has method “setDefaultTopic” (https://docs.spring.io/spring-kafka/api/org/springframework/kafka/core/KafkaTemplate.html#setDefaultTopic(java.lang.String))
I think you can change default topic what you want by using setDefaultTopic before call KafakItemWriter step.
Related
It is my first post to this here and I am not sure if this was covered here before, but here goes: I have a Kafka Streams application, using Processor API, following the topology below:
1. Consume data from an input topic (processor.addSource())
2. Inserts data into a DB (processor.addProcessor())
3. Produce its process status to an output topic (processor.addSink())
App works big time, however, for traceability purposes, I need to have in the logs the moment kstreams produced a message to the output topic, as well as its RecordMetaData (topic, partition, offset).
Example below:
KEY="MY_KEY" OUTPUT_TOPIC="MY-OUTPUT-TOPIC" PARTITION="1" OFFSET="1000" STATUS="SUCCESS"
I am not sure if there is a way to override the default kafka streams producer to add this logging or maybe creating my own producer to plug it on the addSink process. I partially achieved it by implementing my own ExceptionHandler (default.producer.exception.handler), but it only covers the exceptions.
Thanks in advance,
Guilherme
If you configure the streams application to use a ProducerInterceptor, then you should be able to get the information you need. Specifically, implementing the onAcknowledgement() will provide access to everything you listed above.
To configure interceptors in a streams application:
Properties props = new Properties();
// add this configuration in addition to your other streams configs
props.put(StreamsConfig.producerPrefix(ProducerConfig.INTERCEPTOR_CLASSES_CONFIG), Collections.singletonList(MyProducerInterceptor.class));
You can provide more than one interceptor if desired, just add the class name and change the list implementation from a singleton to a regular List. Execution of the interceptors follows the order of the classes in the list.
EDIT: Just to be clear, you can override the provided Producer in Kafka Streams via the KafkaClientSupplier interface, but IMHO using an interceptor is the cleaner approach. But which direction to go is up to you. You pass in your KafkaClientSupplier in an overloaded Kafka Streams constructor.
What exactly is this keyword Context in Hadoop MapReduce world in new API terms?
Its extensively used to write output pairs out of Maps and Reduce, however I am not sure if it can be used somewhere else and what's exactly happening whenever I use context. Is it a Iterator with different name?
What is relation between Class Mapper.Context, Class Reducer.Context and Job.Context?
Can someone please explain this starting with Layman's terms and then going in detail. Not able understand much from Hadoop API documentations.
Thanks for your time and help.
Context object: allows the Mapper/Reducer to interact with the rest of the Hadoop system. It includes configuration data for the job as well as interfaces which allow it to emit output.
Applications can use the Context:
to report progress
to set application-level status messages
update Counters
indicate they are alive
to get the values that are stored in job configuration across map/reduce phase.
The new API makes extensive use of Context objects that allow the user code to communicate with MapRduce system.
It unifies the role of JobConf, OutputCollector, and Reporter from old API.
What exactly is this keyword Context in Hadoop MapReduce world in new API terms?
Its extensively used to write output pairs out of Maps and Reduce, however I am not sure if it can be used somewhere else and what's exactly happening whenever I use context. Is it a Iterator with different name?
What is relation between Class Mapper.Context, Class Reducer.Context and Job.Context?
Can someone please explain this starting with Layman's terms and then going in detail. Not able understand much from Hadoop API documentations.
Thanks for your time and help.
Context object: allows the Mapper/Reducer to interact with the rest of the Hadoop system. It includes configuration data for the job as well as interfaces which allow it to emit output.
Applications can use the Context:
to report progress
to set application-level status messages
update Counters
indicate they are alive
to get the values that are stored in job configuration across map/reduce phase.
The new API makes extensive use of Context objects that allow the user code to communicate with MapRduce system.
It unifies the role of JobConf, OutputCollector, and Reporter from old API.
Hi I am new to Spring Integration and I was wondering if anyone knew how to work around an issue i am having. When I setup the mongo outbound-channel-adapter, I am receiving a list of objects in the custom MappingMongoConverter write method. Does anyone know how to write these to Mongo as individual documents? At the moment I can store them all in one document, but would prefer one document per object in the list.
Many thanks,
Regards.
Simply add a <splitter/> upstream of the outbound channel adapter (it only needs an input channel and output channel - the default splitter will split a Collection into its individual elements).
I am a newbie at Spring Batch and have recently started using it.
I have a requirement where I need to post/write the messages read from each DB record on different queues using single Job. As I have to use reader to read the messages from DB and use processor to decide on which queue I have to post it.
So my question is Can I use single JMSwriter to post the messages on different queues as I have to use single Job and DB Reader.
Thanks in Advance
As I know JMSwriter not supports it (it writes to default destination of jmsTemplate).
But you may just implement your own ItemWriter, inject all jmsTemplates in it and write custom decistion logic to select appropriate destionation and write to it.
Another way - use ClassifierCompositeItemWriter , put a set of JmsWriters to it and select one by your classifier