How to stream data from Kafka to MongoDB by Kafka Connector

Question

I want to stream data from Kafka to MongoDB by using Kafka Connector. I found this one https://github.com/hpgrahsl/kafka-connect-mongodb. But there is no step to do.

After googling, it seems to lead to Confluent Platform what I don't want to use.

Could anyone share me document/guideline how to use kafka-connect-mongodb without using Confluent Platform or another Kafka Connector to stream data from Kafka to MongoDB?

Thank you in advance.

---

What I tried

Step1: I download mongo-kafka-connect-0.1-all.jar from maven central

Step2: copy jar file to a new folder plugins inside kafka (I use Kafka on Windows, so the directory is D:\git\1.libraries\kafka_2.12-2.2.0\plugins)

Step3: Edit file connect-standalone.properties by adding a new line plugin.path=/git/1.libraries/kafka_2.12-2.2.0/plugins

Step4: I add new config file for mongoDB sink MongoSinkConnector.properties

name=mongo-sink
topics=test
connector.class=com.mongodb.kafka.connect.MongoSinkConnector
tasks.max=1
key.ignore=true

# Specific global MongoDB Sink Connector configuration
connection.uri=mongodb://localhost:27017,mongo1:27017,mongo2:27017,mongo3:27017
database=test_kafka
collection=transaction
max.num.retries=3
retries.defer.timeout=5000
type.name=kafka-connect

Step5: run command bin\windows\connect-standalone.bat config\connect-standalone.properties config\MongoSinkConnector.properties

But, I get the error

[2019-07-09 10:19:09,466] WARN The configuration 'offset.flush.interval.ms' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig)
[2019-07-09 10:19:09,467] WARN The configuration 'key.converter.schemas.enable' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig)
[2019-07-09 10:19:09,467] WARN The configuration 'offset.storage.file.filename' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig)
[2019-07-09 10:19:09,468] WARN The configuration 'value.converter.schemas.enable' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig)
[2019-07-09 10:19:09,469] WARN The configuration 'plugin.path' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig)
[2019-07-09 10:19:09,469] WARN The configuration 'value.converter' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig)
[2019-07-09 10:19:09,470] WARN The configuration 'key.converter' was supplied but isn't a known config. (org.apache.kafka.clients.admin.AdminClientConfig)
Jul 09, 2019 10:19:10 AM org.glassfish.jersey.internal.inject.Providers checkProviderRuntime
WARNING: A provider org.apache.kafka.connect.runtime.rest.resources.ConnectorPluginsResource registered in SERVER runtime does not implement any provider interfaces applicable in the SERVER runtime. Due to constraint configuration problems the provider org.apache.kafka.connect.runtime.rest.resources.ConnectorPluginsResource will be ignored.
Jul 09, 2019 10:19:10 AM org.glassfish.jersey.internal.inject.Providers checkProviderRuntime
WARNING: A provider org.apache.kafka.connect.runtime.rest.resources.RootResource registered in SERVER runtime does not implement any provider interfaces applicable in the SERVER runtime. Due to constraint configuration problems the provider org.apache.kafka.connect.runtime.rest.resources.RootResource will be ignored.
Jul 09, 2019 10:19:10 AM org.glassfish.jersey.internal.inject.Providers checkProviderRuntime
WARNING: A provider org.apache.kafka.connect.runtime.rest.resources.ConnectorsResource registered in SERVER runtime does not implement any provider interfaces applicable in the SERVER runtime. Due to constraint configuration problems the provider org.apache.kafka.connect.runtime.rest.resources.ConnectorsResource will be ignored.
Jul 09, 2019 10:19:11 AM org.glassfish.jersey.internal.Errors logErrors
WARNING: The following warnings have been detected: WARNING: The (sub)resource method listConnectors in org.apache.kafka.connect.runtime.rest.resources.ConnectorsResource contains empty path annotation.
WARNING: The (sub)resource method createConnector in org.apache.kafka.connect.runtime.rest.resources.ConnectorsResource contains empty path annotation.
WARNING: The (sub)resource method listConnectorPlugins in org.apache.kafka.connect.runtime.rest.resources.ConnectorPluginsResource contains empty path annotation.
WARNING: The (sub)resource method serverInfo in org.apache.kafka.connect.runtime.rest.resources.RootResource contains empty path annotation.

[2019-07-09 10:19:12,302] ERROR WorkerSinkTask{id=mongo-sink-0} Task threw an uncaught and unrecoverable exception (org.apache.kafka.connect.runtime.WorkerTask)
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:175)
        at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:219)
        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: Converting byte[] to Kafka Connect data failed due to serialization error:
        at org.apache.kafka.connect.json.JsonConverter.toConnectData(JsonConverter.java:344)
        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: com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'this': was expecting 'null', 'true', 'false' or NaN
 at [Source: (byte[])"this is a message"; line: 1, column: 6]
Caused by: com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'this': was expecting 'null', 'true', 'false' or NaN
 at [Source: (byte[])"this is a message"; line: 1, column: 6]
        at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1804)
        at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:703)
        at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._reportInvalidToken(UTF8StreamJsonParser.java:3532)
        at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._reportInvalidToken(UTF8StreamJsonParser.java:3508)
        at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._matchToken2(UTF8StreamJsonParser.java:2843)
        at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._matchTrue(UTF8StreamJsonParser.java:2777)
        at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._nextTokenNotInObject(UTF8StreamJsonParser.java:807)
        at com.fasterxml.jackson.core.json.UTF8StreamJsonParser.nextToken(UTF8StreamJsonParser.java:729)
        at com.fasterxml.jackson.databind.ObjectMapper._readTreeAndClose(ObjectMapper.java:4042)
        at com.fasterxml.jackson.databind.ObjectMapper.readTree(ObjectMapper.java:2571)
        at org.apache.kafka.connect.json.JsonDeserializer.deserialize(JsonDeserializer.java:50)
        at org.apache.kafka.connect.json.JsonConverter.toConnectData(JsonConverter.java:342)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.lambda$convertAndTransformRecord$1(WorkerSinkTask.java:487)
        at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndRetry(RetryWithToleranceOperator.java:128)
        at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndHandleError(RetryWithToleranceOperator.java:162)
        at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execute(RetryWithToleranceOperator.java:104)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.convertAndTransformRecord(WorkerSinkTask.java:487)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.convertMessages(WorkerSinkTask.java:464)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.poll(WorkerSinkTask.java:320)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.iteration(WorkerSinkTask.java:224)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.execute(WorkerSinkTask.java:192)
        at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:175)
        at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:219)
        at java.util.concurrent.Executors$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)
[2019-07-09 10:19:12,305] ERROR WorkerSinkTask{id=mongo-sink-0} Task is being killed and will not recover until manually restarted (org.apache.kafka.connect.runtime.WorkerTask)

What configuration did I set wrong or I miss anything?

---

I fixed it. Now, I can stream data from Kafka to MongoDB succesfully

My fix is:

1. move my kafka to C:\kafka_2.12-2.2.0
2. update plugin_path corresponding to new path
3. update config file connect-standalone.properties

Answer 1

There is an official source and sink connector from MongoDB themselves. It is available on Confluent Hub: https://www.confluent.io/hub/mongodb/kafka-connect-mongodb

If you don't want to use Confluent Platform you can deploy Apache Kafka yourself - it includes Kafka Connect already. Which plugins (connectors) you use with it is up to you. In this case you would be using Kafka Connect (part of Apache Kafka) plus kafka-connect-mongodb (provided by MongoDB).

Documentation on how to use it is here: https://docs.mongodb.com/kafka-connector/current/

Answer 2

Even though this question is a little old. Here is how I connected kafka_2.12-2.6.0 to mongodb (version 4.4) on ubuntu system:

a. Download mongodb connector '*-all.jar' from here .Mongodb-kafka connector with 'all' at the end will contain all connector dependencies also.

b. Drop this jar file in your kafka's lib folder

c. Configure 'connect-standalone_bare.properties' as:

bootstrap.servers=localhost:9092
key.converter=org.apache.kafka.connect.json.JsonConverter
value.converter=org.apache.kafka.connect.json.JsonConverter
key.converter.schemas.enable=false
value.converter.schemas.enable=false
offset.storage.file.filename=/tmp/connect.offsets
offset.flush.interval.ms=10000

d. Configure 'MongoSinkConnector.properties' as:

name=mongo-sink
topics=test
connector.class=com.mongodb.kafka.connect.MongoSinkConnector
tasks.max=1
key.ignore=true
connection.uri=mongodb://localhost:27017
database=test_kafka
collection=transaction
max.num.retries=3
retries.defer.timeout=5000
type.name=kafka-connect
schemas.enable=false

Place both 'properties' file here: $HOME/Documents/kafka/config

e. Start connector-process, as:

export folder_path="$HOME/Documents/kafka/config"
connect-standalone.sh  $folder_path/connect-standalone_bare.properties $folder_path/MongoSinkConnector.properties

e. In kafka, start zookeeper-server and also kafka-server. Create topic 'test'. In mongod server, create database 'test_kafka' and under it a collection, 'transaction'.

f. Start kafka producer:

kafka-console-producer.sh --broker-list localhost:9092  --topic test

And make an entry: {"abc" : "def" }

You should be able to see it in mongodb (db.transaction.find() ).