Kafka Rest API发送Avro格式消息

Kafka Rest 及 Schema-Registry的部署本文不做介绍。
如果需要使用java 发送Avro格式消息，请参考Kafka Schema Registry 使用教程(JAVA)。
下面示例使用Rest 和Schema-Registry API 发送消息。

1. 创建topic: schema-test。

2. 使用schema-registry API注册Schema，获取schema id

   1. 检查schema是否存在：
   curl -X POST \ 
   -H "Content-Type: application/vnd.schemaregistry.v1+json" \
   -H "Accept: application/vnd.schemaregistry.v1+json,application/vnd.schemaregistry+json, application/json" \
   "http://schema-host:port/subjects/schema-test-value"
   Response:
   {
       "error_code": 40401,
       "message": "Subject not found."
   }
   
   2. 注册schema:
   curl -X POST \ 
   -H "Content-Type: application/vnd.schemaregistry.v1+json" \
   -H "Accept: application/vnd.schemaregistry.v1+json,application/vnd.schemaregistry+json, application/json" \
   --data '{"schema":"{\"type\": \"record\", \"name\": \"User\", \"fields\": [{\"name\": \"name\", \"type\": \"string\"},{\"name\": \"age\", \"type\": \"int\"}]}"}' \
   "http://schema-host:port/subjects/schema-test-value/versions"
   // 返回的id在发送消息时会用到
   Response:
   {
       "id": 484
   }                
   

3. 使用Rest API向topic发送消息

   curl -X POST \ 
   -H "Content-Type: application/vnd.kafka.avro.v2+json" \
   -H "Accept: application/vnd.kafka.v2+json, application/vnd.kafka+json, application/json" \
   --data '{"value_schema_id":484,"records":[{"value":{"name":"kyle","age":10}},{"value":{"name":"lola","age":11}}]}' \
   "http://rest-host:port/topics/schema-test"
   Response:
   {
       "offsets": [
           {
               "partition": 2,
               "offset": 0,
               "error_code": null,
               "error": null
           },
           {
               "partition": 1,
               "offset": 0,
               "error_code": null,
               "error": null
           }
       ],
       "key_schema_id": null,
       "value_schema_id": 484
   }
   

4. 创建 consumer 实例

   curl -X POST \ 
   -H "Content-Type: application/vnd.kafka.v2+json" \
   --data '{"name":"schema-test_consumer","format":"avro","auto.offset.reset":"earliest","auto.commit.enable":"false"}' \
   "http://rest-host:port/consumers/schema-test-group"
   Response:
   {
       "instance_id": "schema-test_consumer",
       "base_uri": "http://rest-host:port/consumers/schema-test-group/instances/schema-test_consumer"
   }
   

5. 订阅topic

   curl -X POST \ 
   -H "Content-Type: application/vnd.kafka.v2+json" \
   --data '{"topics":["schema-test"]}' \
   "http://rest-host:port/consumers/schema-test-group/instances/schema-test_consumer/subscription"
   Response:
   No Content
   

6. 消费数据

   curl -X GET \ 
   -H "Accept: application/vnd.kafka.avro.v2+json" \
   "http://rest-host:port/consumers/schema-test-group/instances/schema-test_consumer/records?timeout=3000&max_bytes=300000"
   Response:
   [
       {
           "key": null,
           "value": {
               "name": "kyle",
               "age": 10
           },
           "partition": 2,
           "offset": 0,
           "topic": "schema-test"
       },
       {
           "key": null,
           "value": {
               "name": "lola",
               "age": 11
           },
           "partition": 1,
           "offset": 0,
           "topic": "schema-test"
       }
   ]
   

   其他更详细的API及参数请参阅官网 .

   Kafka Rest Api

   Schema-registry API