GET /consumers/{group: string}/instances/{instance: string}/topics/{topic: string}

Consumes messages by a specific consumer from a topic .

Description

Depending on the configuration, the type of information retrieved has different behavior. See the streams.default.stream and rest.proxy.backend parameters in Configuration Parameters.

Table 1. Parameters
Parameters Defined Response
streams.default.stream is defined

Consumes messages by a specific consumer from a MapR Streams topic if the consumer has not been subscribed for other topic yet. The user could pass fully qualified topic name or not. If a fully qualified topic name is not used, messages are consumed from the topic in the default stream path.

streams.default.stream is not defined and rest.proxy.backend=streams Consumes messages by a specific consumer from a MapR Streams topic if the consumer has not been subscribed to another topic. The fully qualified topic name must pass the fully qualified topic name that contains the stream path.
streams.default.stream is not defined and rest.proxy.backend=hybrid Consumes messages by a specific consumer into MapR Streams topic if topic name starts with a forward slash (/) and a colon (:). Otherwise, consumes messages by a specific consumer from a specific Apache Kafka topic.
Note: The first time a consumer reads from a topic, it subscribes for that topic and that consumer cannot be used to read from other topics.
Table 2. Parameters
Parameters Description
group_name (string) The name of the consumer group.
instance (string) The ID of the consumer instance.
topic_name (string) The topic to consume messages from.

Syntax

http://<host>:8082/topics/<group_name>/instances/<instance_id>/topics/<topic_name>

Request Example

curl -X GET -H "Accept: application/vnd.kafka.binary.v1+json" 
http://localhost:8082/consumers/grouptest/instances/user/topics/testtopic1

Response Example

[
  {
    "key":"a2v5",
    "value":"Y29uZmx1ZW50",
    "topic":"/streaming_data/stream:testtopic1",
    "partition":0,"offset":1
  },
  {
    "key":"a2v5",
    "value":"Y29uZmx1ZW50",
    "topic":"/streaming_data/stream:testtopic1",
    "partition":0,"offset":2
  }
]