Bash script to process Kafka messages

Question

I want to use shell scripts to consume kafka messages and return to status. I found that my script wasn't efficient enough.

Can I write this script better?

I want to output kafka-console-consumer.sh execution time, how do I write it?

The input result can be kafka_Check|consumer:0|consumer_time:0.3s

#!/bin/bash
result=""
vesrion=`ps -ef|grep -v grep|grep -o "kafka.\{,20\}[0-9]-sources.jar"|awk -F '-' '{print 2ドル}'|cut -d . -f 1,-3|tr -d .`
OUT_FLAG() {
 local check_value=1ドル
 local result_value=2ドル
 if [ "${check_value}" -eq 0 ];then
 result="$result|${result_value}:0"
 else
 result="$result|${result_value}:1"
 fi
}
get_kafka_home(){
 local kafka_home_count=`ps -ef|grep kafka-tool|grep -v grep| wc -l`
 if [ $kafka_home_count -ge 1 ];then
 kafka_home=`ps -ef|grep kafka\.kafka|grep -v grep | awk -F '/bin/../libs' '{print 2ドル}'|awk -F ':' '{print 2ドル}'`
 else
 echo "could not found kafka_home."
 exit 1
 fi
}
consumer(){
 local consumer_mes=0
 TOPIC=`$kafka_home/bin/kafka-topics.sh --zookeeper localhost:2181 --list|grep -v "__consumer_offsets"|grep -m 1 "[a-zA-Z]"`
 if [ ${vesrion} -gt 0102 ]; then
 timeout -k 3s 3s $kafka_home/bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic $TOPIC --from-beginning --max-messages 1 &>/dev/null
 consumer_mes=$?
 OUT_FLAG ${consumer_mes} "consumer_flag"
 else
 timeout -k 3s 3s $kafka_home/bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic $TOPIC --from-beginning --new-consumer --max-messages 1 &>/dev/null
 consumer_mes=$?
 OUT_FLAG ${consumer_mes} "consumer_flag"
 fi
}
main(){
 get_kafka_home
 config_file="$kafka_home/config/server.properties"
 if [[ $(ss -ntupl|grep -w '9092' &>/dev/null) -ne 0 ]]&&[[ $(ss -ntupl|grep -w '2181' &>/dev/null) -ne 0 ]]
 then
 exit 1
 else
 consumer
 fi
 echo "Kafka_Check$result"
}
main

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Answer 1

I'm not good enough with shell programming to really dig into your code, but I have some suggestions nonetheless!

• Make sure you know where the inefficiency is.
  There's no bennefit from optimizing stuff that isn't the bottleneck. For example, if most of the time that your script takes to run is spent running the stuff from $kafka_home/bin/, then optimizing your own code won't speed things up.
• Avoid redundancy.
  You're calling ps -ef three times. Can't you just call ps -ef|grep -v grep once and save it to a variable for use in subsequent commands?
• Consider swapping in more modern tools.
  I don't understand what you're doing well enough to question your choice to use bash, but grep looks like low hanging fruit. Several alternatives exist; I've heard ripgrep is the best.
• Consider using $() instead of ``.