Error deserializing Avro message on Sink Connector - apache-kafka

Question

I am getting error deserializing Avro message while trying to consume avro message from topic and dump them into postgres DB.
Here is my Producer config:
spring
Kafka
producer:
bootstrap-servers: localhost:9092
key-serializer: io.confluent.kafka.serializers.KafkaAvroSerializer
value-serializer: io.confluent.kafka.serializers.KafkaAvroSerializer
properties:
schema.registry.url: http://localhost:8081
sink-connector config:
{
"name": "jdbc_source_postgres_avro",
"config": {
"connector.class": "io.confluent.connect.jdbc.JdbcSinkConnector",
"connection.url": "jdbc:postgres://localhost:5432/kafka-test",
"key.converter": "io.confluent.connect.avro.AvroConverter",
"value.converter": "io.confluent.connect.avro.AvroConverter",
"key.converter.schema.registry.url": "http://localhost:8081",
"value.converter.schema.registry.url": "http://localhost:8081",
"connection.user": "postgres",
"connection.password": "password",
"topics": "docker-avro-topic",
"auto.create": "true",
"auto.offset.reset": "latest",
"name": "jdbc_source_postgres_avro"
}
docker-image for connect:
connect:
image: cnfldemos/kafka-connect-datagen:0.1.3-5.3.1
hostname: connect
container_name: connect
depends_on:
- zookeeper
- broker
- schema-registry
ports:
- "8083:8083"
environment:
CONNECT_BOOTSTRAP_SERVERS: 'broker:29092'
CONNECT_REST_ADVERTISED_HOST_NAME: connect
CONNECT_REST_PORT: 8083
CONNECT_GROUP_ID: compose-connect-group
CONNECT_CONFIG_STORAGE_TOPIC: docker-connect-configs
CONNECT_OFFSET_STORAGE_TOPIC: docker-connect-offsets
CONNECT_STATUS_STORAGE_TOPIC: docker-connect-status
CONNECT_KEY_CONVERTER: io.confluent.connect.avro.AvroConverter
CONNECT_KEY_CONVERTER_SCHEMA_REGISTRY_URL: 'http://schema-registry:8081'
CONNECT_VALUE_CONVERTER: io.confluent.connect.avro.AvroConverter
CONNECT_VALUE_CONVERTER_SCHEMA_REGISTRY_URL: 'http://schema-registry:8081'
CONNECT_INTERNAL_KEY_CONVERTER: "org.apache.kafka.connect.json.JsonConverter"
CONNECT_INTERNAL_VALUE_CONVERTER: "org.apache.kafka.connect.json.JsonConverter"
CONNECT_LOG4J_ROOT_LOGLEVEL: "INFO"
CONNECT_LOG4J_LOGGERS: "org.apache.kafka.connect.runtime.rest=WARN,org.reflections=ERROR"
CONNECT_CONFIG_STORAGE_REPLICATION_FACTOR: "1"
CONNECT_OFFSET_STORAGE_REPLICATION_FACTOR: "1"
CONNECT_STATUS_STORAGE_REPLICATION_FACTOR: "1"
CONNECT_ZOOKEEPER_CONNECT: 'zookeeper:2181'
And finally the error log:
org.apache.kafka.connect.errors.ConnectException: Tolerance exceeded
in error handler at
org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndHandleError(RetryWithToleranceOperator.java:178)
at
org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execute(RetryWithToleranceOperator.java:104)
at
org.apache.kafka.connect.runtime.WorkerSinkTask.convertAndTransformRecord(WorkerSinkTask.java:487)
at
org.apache.kafka.connect.runtime.WorkerSinkTask.convertMessages(WorkerSinkTask.java:464)
at
org.apache.kafka.connect.runtime.WorkerSinkTask.poll(WorkerSinkTask.java:320)
at
org.apache.kafka.connect.runtime.WorkerSinkTask.iteration(WorkerSinkTask.java:224)
at
org.apache.kafka.connect.runtime.WorkerSinkTask.execute(WorkerSinkTask.java:192)
at
org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:177)
at
org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:227)
at
java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266) at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748) Caused by:
org.apache.kafka.connect.errors.DataException: Failed to deserialize
data for topic docker-avro-topic to Avro: at
io.confluent.connect.avro.AvroConverter.toConnectData(AvroConverter.java:110)
at
org.apache.kafka.connect.runtime.WorkerSinkTask.lambda$convertAndTransformRecord$1(WorkerSinkTask.java:487)
at
org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndRetry(RetryWithToleranceOperator.java:128)
at
org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndHandleError(RetryWithToleranceOperator.java:162)...
13 more Caused by:
**org.apache.kafka.common.errors.SerializationException: Error
deserializing Avro message for id 101 Caused by:
java.net.ConnectException: Connection refused (Connection refused) at
java.net.PlainSocketImpl.socketConnect(Native Method)** at
java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at
java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at
java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) at
java.net.Socket.connect(Socket.java:589) at
sun.net.NetworkClient.doConnect(NetworkClient.java:175) at
sun.net.www.http.HttpClient.openServer(HttpClient.java:463) at
sun.net.www.http.HttpClient.openServer(HttpClient.java:558) at
sun.net.www.http.HttpClient.<init>(HttpClient.java:242) at
sun.net.www.http.HttpClient.New(HttpClient.java:339) at
sun.net.www.http.HttpClient.New(HttpClient.java:357 at
sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1220)
at
sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1156)
at
sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1050)
at
sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:984)
at
sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1564)
at
sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
at
java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:480)

Answer 1

You've configured Kafka Connect to look for a Schema Registry that is running on the same container:
"value.converter.schema.registry.url": "http://localhost:8081",
but it's not, hence:
java.net.ConnectException: Connection refused (Connection refused)
Since you've already specified the Schema Registry config in your Kafka Connect docker environment variables then assuming you actually do have the Schema Registry running on a container that can be resolved as schema-registry from the Kafka Connect container, you can simply remove the schema.registry.url configuration lines from the actual Connector configuration.