Pdf Mq Channel Authentication Records
Channels are connected to message backends using connectors. Connectors are configured to map incoming messages to a specific channel (consumed by the application) and collect outgoing messages sent to a specific channel. Each connector is dedicated to a specific messaging technology. For example, the connector dealing with Kafka is named smallrye-kafka.
If you have a single connector on your classpath, you can omit the connector attribute configuration.Quarkus automatically associates orphan channels to the (unique) connector found on the classpath.Orphans channels are outgoing channels without a downstream consumer or incoming channels without an upstream producer.
As with the previous Message example, if your injected channel receives payloads (Multi), it acknowledges the message automatically, and support multiple subscribers.If you injected channel receives Message (Multi), you will be responsible for the acknowledgment and broadcasting.We will explore sending broadcast messages in Broadcasting messages on multiple consumers.
Injecting @Channel("prices") or having @Incoming("prices") does not automatically configure the application to consume messages from Kafka.You need to configure an inbound connector with mp.messaging.incoming.prices... or have an @Outgoing("prices") method somewhere in your application (in which case, prices will be an in-memory channel).
When a message produced from a Kafka record is acknowledged, the connector invokes a commit strategy.These strategies decide when the consumer offset for a specific topic/partition is committed.Committing an offset indicates that all previous records have been processed.It is also the position where the application would restart the processing after a crash recovery or a restart.
throttled keeps track of received messages and commits an offset of the latest acked message in sequence (meaning, all previous messages were also acked).This strategy guarantees at-least-once delivery even if the channel performs asynchronous processing.The connector tracks the received records and periodically (period specified by auto.commit.interval.ms, default: 5000 ms) commits the highest consecutive offset.The connector will be marked as unhealthy if a message associated with a record is not acknowledged in throttled.unprocessed-record-max-age.ms (default: 60000 ms).Indeed, this strategy cannot commit the offset as soon as a single record processing fails.If throttled.unprocessed-record-max-age.ms is set to less than or equal to 0, it does not perform any health check verification.Such a setting might lead to running out of memory if there are "poison pill" messages (that are never acked).This strategy is the default if enable.auto.commit is not explicitly set to true.
latest commits the record offset received by the Kafka consumer as soon as the associated message is acknowledged (if the offset is higher than the previously committed offset).This strategy provides at-least-once delivery if the channel processes the message without performing any asynchronous processing.This strategy should not be used in high load environment, as offset commit is expensive. However, it reduces the risk of duplicates.
ignore performs no commit. This strategy is the default strategy when the consumer is explicitly configured with enable.auto.commit to true.It delegates the offset commit to the underlying Kafka client.When enable.auto.commit is true this strategy DOES NOT guarantee at-least-once delivery.SmallRye Reactive Messaging processes records asynchronously, so offsets may be committed for records that have been polled but not yet processed.In case of a failure, only records that were not committed yet will be re-processed.