How to rewind and look at previous offset in a partition using Kafka Go client's Consumer

I am new to Kafka. Currently I am experimenting with this Channel Consumer example from Confluent Inc's Github repo

From what I know, consumers are separated into groups. Each group has their own offset in the partition. Let's say I have 40 messages in a particular topic let's call it, owner_commands. A consumer, belongs to the dog group, joins and begins to consume those 40 messages.

When I disconnected and reconnected this consumer, I noticed that messages don't show up anymore. It says that I have reached the end of file. However, if I join the cluster with another consumer, which belongs to a different group (say cat) I get to read those 40 messages again.

Do you know if there is a way for consumers in the dog group to rewind and replay those messages again using Kafka's Go API. I looked at the source code for Kafka Golang API, I couldn't find anything that indicates to me that I can rewind and look at a particular message in the past.

Thank you

You could use CommitOffsets and just commit back to the offset you want to rewind to. The next poll will start from that offset.

CommitOffsets is documented here:
http://docs.confluent.io/current/clients/confluent-kafka-go/index.html#Consumer.CommitOffsets

Outside of the API, there's functionality in the kafka-consumer-groups command to move the position of consumer groups as well. This is released with Apache Kafka 0.11.