Calculate average number of records per JSON record in Kafka topic

kafka_num_of_tags.sh

#!/bin/bash
# returns an average number of key-value pairs per json record
# requires jq and kafka-tools

BOOTSTRAP_SERVERS="some-server-1:9092,some-server-2:9092"
TOPIC_NAME=$1
NUM_MESSAGES=${2:-10000}

TOTAL=$(kafka-console-consumer --topic ${TOPIC_NAME} --bootstrap-server ${BOOTSTRAP_SERVERS} \
  --from-beginning --max-messages ${NUM_MESSAGES} \
  | jq '.[] | length' | paste -sd+ | bc)
  
AVG=$(echo "${TOTAL} / ${NUM_MESSAGES}" | bc -l)
printf %.f\\n ${AVG}