Monday, February 21, 2022

[SOLVED] Running multiple instances of a shell function parallelly

Issue

I'm having a shell script as follows.

#!/bin/bash

myfunc() {
   #do something (call a rest service)
   sleep 300
   status=$(get status of the operation performed above)
   while [ "$status" != "succeeded" ]; do
       #do something (call a rest service)
       sleep 300
       status=$(get status of the operation performed above)
   done
}

a=0

while [ $a -lt 1000 ]
do
   a=`expr $a + 1`
   myfunc
done

In best case, above script takes at least 5*1000=5000 seconds to complete running.

Is there a way to make the myfunc call parallel so that we can let the while loop to spawn multiple running instances of the myfunc??

Note: Somehow, this script should wait until all instances of myfunc executions are completed.


Solution

I think you could update your script as follow:

#!/bin/bash

myfunc() {
   job_id=$1
   echo "Started job ${job_id}..."

   #do something (call a rest service)
   sleep 300
   status=$(get status of the operation performed above)
   while [ "$status" != "succeeded" ]; do
       #do something (call a rest service)
       sleep 300
       status=$(get status of the operation performed above)
   done

   echo "Terminated job ${job_id}."
}

a=0

while [ $a -lt 1000 ]
do
   echo $a
   a=(($a + 1))
   myfunc $a &
done

wait
echo "Parallel execution terminated."


Answered By - Antonio Petricca
Answer Checked By - Marie Seifert (WPSolving Admin)
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