Not able to locate ojdbc jar in kafka-connect - docker

Question

I am working on to create pipeline to stream data from oracle database. I am using below compose file to UP the required services for Kafka and using command option to download the ojdbc jar. I have explicitly checked the curl command used in this compose file and I am able to download jar and this should work fine here also.
I am able to UP the stacks of all required services without any issue.
But, when I am navigating to kafka-connect-jdbc folder to look for ojdbc jar, I couldn't see there. Ideally, it should be downloaded and placed in the kafka-connect-jdbc jar.
docker-compose.yml file:
---
version: '2'
services:
zookeeper:
image: confluentinc/cp-zookeeper:5.4.0
hostname: zookeeper
container_name: zookeeper
ports:
- "2181:2181"
environment:
ZOOKEEPER_CLIENT_PORT: 2181
ZOOKEEPER_TICK_TIME: 2000
broker:
image: confluentinc/cp-kafka:5.4.0
hostname: broker
container_name: broker
depends_on:
- zookeeper
ports:
- "29092:29092"
- "9092:9092"
environment:
KAFKA_BROKER_ID: 1
KAFKA_ZOOKEEPER_CONNECT: 'zookeeper:2181'
KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: PLAINTEXT:PLAINTEXT,PLAINTEXT_HOST:PLAINTEXT
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://broker:29092,PLAINTEXT_HOST://localhost:9092
KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
KAFKA_TRANSACTION_STATE_LOG_MIN_ISR: 1
KAFKA_TRANSACTION_STATE_LOG_REPLICATION_FACTOR: 1
KAFKA_GROUP_INITIAL_REBALANCE_DELAY_MS: 0
schema-registry:
image: confluentinc/cp-schema-registry:5.4.0
hostname: schema-registry
container_name: schema-registry
depends_on:
- zookeeper
- broker
ports:
- "8081:8081"
environment:
SCHEMA_REGISTRY_HOST_NAME: schema-registry
SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: 'zookeeper:2181'
kafka-connect:
image: confluentinc/cp-kafka-connect:5.4.0
hostname: kafka-connect
container_name: kafka-connect
depends_on:
- broker
- schema-registry
ports:
- "8083:8083"
environment:
CONNECT_BOOTSTRAP_SERVERS: "broker:29092"
CONNECT_REST_ADVERTISED_HOST_NAME: "kafka-connect"
CONNECT_REST_PORT: 8083
CONNECT_GROUP_ID: kafka-connect
CONNECT_CONFIG_STORAGE_TOPIC: kafka-connect-configs
CONNECT_CONFIG_STORAGE_REPLICATION_FACTOR: 1
CONNECT_OFFSET_FLUSH_INTERVAL_MS: 10000
CONNECT_OFFSET_STORAGE_TOPIC: kafka-connect-offsets
CONNECT_OFFSET_STORAGE_REPLICATION_FACTOR: 1
CONNECT_STATUS_STORAGE_TOPIC: kafka-connect-status
CONNECT_STATUS_STORAGE_REPLICATION_FACTOR: 1
CONNECT_KEY_CONVERTER: org.apache.kafka.connect.storage.StringConverter
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_ZOOKEEPER_CONNECT: 'zookeeper:2181'
CONNECT_PLUGIN_PATH: "/usr/share/java,/usr/share/confluent-hub-components"
CONNECT_LOG4J_LOGGERS: org.apache.zookeeper=ERROR,org.I0Itec.zkclient=ERROR,org.reflections=ERROR
command:
- /bin/bash
- -c
- /
cd /usr/share/java/kafka-connect-jdbc/
echo "fetching jar"
curl https://maven.xwiki.org/externals/com/oracle/jdbc/ojdbc8/12.2.0.1/ojdbc8-12.2.0.1.jar -o ojdbc8-12.2.0.1.jar
/etc/confluent/docker/run &
sleep infinity
ksqldb-server:
image: confluentinc/ksqldb-server:0.9.0
hostname: ksqldb-server
container_name: ksqldb-server
depends_on:
- broker
- kafka-connect
ports:
- "8088:8088"
environment:
KSQL_CONFIG_DIR: "/etc/ksql"
KSQL_BOOTSTRAP_SERVERS: "broker:29092"
KSQL_HOST_NAME: ksqldb-server
KSQL_LISTENERS: "http://0.0.0.0:8088"
KSQL_CACHE_MAX_BYTES_BUFFERING: 0
KSQL_KSQL_SCHEMA_REGISTRY_URL: "http://schema-registry:8081"
KSQL_PRODUCER_INTERCEPTOR_CLASSES: "io.confluent.monitoring.clients.interceptor.MonitoringProducerInterceptor"
KSQL_CONSUMER_INTERCEPTOR_CLASSES: "io.confluent.monitoring.clients.interceptor.MonitoringConsumerInterceptor"
KSQL_KSQL_CONNECT_URL: "http://connect:8083"
ksqldb-cli:
image: confluentinc/ksqldb-cli:0.9.0
container_name: ksqldb-cli
depends_on:
- broker
- kafka-connect
- ksqldb-server
entrypoint: /bin/sh
tty: true
rest-proxy:
image: confluentinc/cp-kafka-rest:5.4.0
depends_on:
- zookeeper
- broker
- schema-registry
ports:
- "8082:8082"
hostname: rest-proxy
container_name: rest-proxy
environment:
KAFKA_REST_HOST_NAME: rest-proxy
KAFKA_REST_BOOTSTRAP_SERVERS: 'broker:29092'
KAFKA_REST_LISTENERS: "http://0.0.0.0:8082"
KAFKA_REST_SCHEMA_REGISTRY_URL: 'http://schema-registry:8081'

Answer 1

I suggest that you download the JAR outside of Docker, then volume mount it. That way, your container isn't always trying to redownload when you restart it.
mkdir jdbc-jars
curl https://maven.xwiki.org/externals/com/oracle/jdbc/ojdbc8/12.2.0.1/ojdbc8-12.2.0.1.jar -o jdbc-jars/ojdbc8-12.2.0.1.jar
...
...
CONNECT_PLUGIN_PATH: "/usr/share/java,/usr/share/confluent-hub-components"
CONNECT_LOG4J_LOGGERS: org.apache.zookeeper=ERROR,org.I0Itec.zkclient=ERROR,org.reflections=ERROR
volumes:
- ./jdbc-jars:/usr/share/java/kafka-connect-jdbc/lib
ksqldb-server:
image: confluentinc/ksqldb-server:0.9.0