Kafka Connect - File Source connector

Reading File with connect. Adapted from Quickstart kafka connect

• Start the demo docker image with bash

docker run   -ti --name connect-demo -p 8083:8083 -p 8081:8081 -p 2181:2181 -p 9092:9092 confluentinc/docker-demo-base:3.3.0 //bin//bash 

• Install jq

apt-get update
apt-get install jq

• Start Kafka

confluent start

• Is the connector available in /etc/kafka

confluent list connectors | grep file-source

file-source

• Connector configuration /etc/kafka/connect-file-source.properties

cat /etc/kafka/connect-file-source.properties

# User defined connector instance name.
name=local-file-source
# The class implementing the connector
connector.class=FileStreamSource
# Maximum number of tasks to run for this connector instance
tasks.max=1
# The input file (path relative to worker's working directory)
# This is the only setting specific to the FileStreamSource
file=test.txt
# The output topic in Kafka
topic=connect-test

• Without schema registry, the default converter must be set to JSON by setting the key.converter and value.converter properties. Why ????
• Seed the file <note tip>The working path is the current directory because we have started the service from this path</note>

for i in {1..3}; do echo "log line $i for nico demo"; done > test.txt
cat test.txt

log line 1 for nico demo
log line 2 for nico demo
log line 3 for nico demo

• Load the connector. Upon success it will print the connector’s configuration.

confluent load file-source -d /etc/kafka/connect-file-source.properties

{                                          
  "name": "file-source",                   
  "config": {                              
    "connector.class": "FileStreamSource", 
    "tasks.max": "1",                      
    "file": "test.txt",                    
    "topic": "connect-test",               
    "name": "file-source"                  
  },                                       
  "tasks": []                              
}

• Global Status (All connectors)

confluent status connectors

[
  "file-source"
]

• Status of the file-source connector

confluent status file-source

{                                    
  "name": "file-source",             
  "connector": {                     
    "state": "RUNNING",              
    "worker_id": "172.17.0.2:8083"   
  },                                 
  "tasks": [                         
    {                                
      "state": "RUNNING",            
      "id": 0,                       
      "worker_id": "172.17.0.2:8083" 
    }                                
  ]                                  
}

• Consume and let the console open. kafka-avro-console-consumer is used because the data has been stored in Kafka using Avro format.

kafka-avro-console-consumer --bootstrap-server localhost:9092 --topic connect-test --from-beginning

"log line 1 for nico demo"
"log line 2 for nico demo"
"log line 3 for nico demo"

• Produce - Start a new console, add lines to the text file

docker exec -it connect-demo //bin//bash
for i in {4..6}; do echo "log line $i for nico demo"; done >> test.txt

• Check the consumer

"log line 4 for nico demo"
"log line 5 for nico demo"
"log line 6 for nico demo"