THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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The goal is to add Kafka Rest Server /Proxy to Kafka Repository. This will allow any language/tool that
can work with HTTP to produce and consume messages, and perform administrative actions with Kafka service.
Why add Kafka Rest Server
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to Kafka?
There are already some open-source REST proxies are available. Some are specific to a particular user cases
Confluent REST Proxy got comprehensive interface. We want to add Kafka Rest Server to Kafka for the following reasons.
1) Many data Infra tools comes up with Rest Interface. It is useful to have inbuilt Rest API support for Produce,
Consume messages and admin interface for integrating with external management and provisioning tools.
2) Shipping Kafka Rest Server as part of a normal Kafka release makes it immediately available to every user that downloads Kafka.
3) Helps to maintain the version compatibility between Kafka and Rest Server.
Some of the good practices and ideas will be borrowed from existing tools.
Proposed Changes
Rest Server
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:
The REST Proxy server is a separate server, sitting between Kafka cluster and client applications. It is wrapper around existing client libraries.
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content types in Content-Type and Accept headers to make the format of the data explicit. This approach is borrowed from Confluent Rest Proxy.
Supported Content-Types are: application/vnd.kafka.binary.v1+json, application/vnd.kafka.json.v1+json
Supported Content-Types are: application/vnd.kafka.binary.v1+json, application/vnd.kafka.json.v1+json
Rest Proxy server can be easily scaled by deploying multiple proxy instances. This way we can spread the load across multiple proxy instance
Producer API:
REST Proxy server accepts produce requests for specific topics or partitions. It internally uses java producer instance to write messages into Kafka.
Consumer API:
REST Proxy server uses the consumer API to consume the messages from the subscribed topic on behalf of the specified consumer group.
When a message is consumed on behalf of a consume group for the first time, then Kafka Consumer instance joins the consumer group
and subscribes to the topic. All Consumer instances that are currently members of that group and subscribed to that topic divide
topic partitions among themselves. If a Consumer instance has not consumed from a particular topic on behalf of a particular
consumer group for configured interval, then it unsubscribes from the topic on behalf of that group. Offset commit can be either
automatic or manual as requested by the user. We can also retrieve the messages for a consumer, from a specific partition,
starting with an offset.
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HTTP/1.1 200 OK Content-Type: application/vnd.kafka.v1+json { "offsets": [ { "partition": 2, "offset": 1001 }, { "partition": 1, "offset": 101 2 } ] } |
POST /topics/:topicName/partitions/:partition
Description : Produce messages to one partition of the topic
Parameters:
topicName (String) - topic name
partition (int) - partition number
Request:
JSON Object contains array of produce records
Response:
JSON Object contains response objects
Status Codes:
404 Not Found
Error Code 40401 - topic Not Found
Error Code 40402 - partition Not Found
500 Internal Server Error
Error Code 50001 - Kafka Error
Example request:
POST /topics/test/partitions/1 HTTP/1.1 Host:kafkarest.host.com Content-Type: application/vnd.kafka.binary.v1+json Accept: application/vnd.kafka.v1+json { "records": [ { "key": "a2V5", "value": "dmFsdWU=" }, { "value": "dmFsdWU=" } ] } |
Example response:
HTTP/1.1 200 OK Content-Type: application/vnd.kafka.v1+json { "offsets": [ { "partition": 1, "offset": 100 1, }, { "partition": 1, "offset": 101 2, } ] } |
Consumer APIs:
GET /topics/:topic_name/partitions/:partition?offset=(int)
Description : Consume messages from one partition of the topic.
Parameters:
topic_name (String) - topic name
partition (int) - partition number
offset (int) - offset to fetch
Response:
JSON Object contains response objects
Status Codes:
404 Not Found
Error Code 40401 - topic Not Found
Error Code 40402 - partition Not Found
500 Internal Server Error
Error Code 50001 - Kafka Error
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