New recipe for how to keep track of successful publishing to Kafka.

recipes/recipe-11-keep-track-of-successful-send-kafka.adoc

@@ -0,0 +1,48 @@
+# Keeping track of successful sending of records (producing) in Kafka
+
+## Problem Statement
+
+I have a Kafka producer application and I want to keep track of all my successful sedings.
+
+## Solution
+
+Let us assume that we have this following supplier in the application.
+
+```
+@Bean
+	public Supplier<Message<String>> supplier() {
+		return () -> MessageBuilder.withPayload("foo").setHeader(KafkaHeaders.MESSAGE_KEY, "my-foo").build();
+	}
+```
+
+Then, we need to define a new `MessageChannel` bean to capture all the successful send information.
+
+```
+@Bean
+	public MessageChannel fooRecordChannel() {
+		return new DirectChannel();
+	}
+```
+
+Next, define this property in the application configuration to provide the bean name for the `recordMetadataChannel`.
+
+```
+spring.cloud.stream.kafka.bindings.supplier-out-0.producer.recordMetadataChannel: fooRecordChannel
+```
+
+At this point, successful sent information will be sent to the `fooRecordChannel`.
+
+You can write an `IntegrationFlow` as below to see the information.
+
+```
+@Bean
+public IntegrationFlow integrationFlow() {
+    return f -> f.channel("fooRecordChannel")
+                 .handle((payload, messageHeaders) -> payload);
+}
+```
+
+In the `handle` method, the payload is what got sent to Kafka and the message headers contain a special key called `kafka_recordMetadata`.
+Its value is a `RecordMetadata` that contains information about topic partition, current offset etc.
+
+