I have requirement where I need to fail parent if any one of the child process fails. Here is the code snippet
for i in 1 2 3 4 5 6 7 8 9 10
do
child_script $i &
done
wait
I need to fail my main script if any one of my child process fails
wait allows to specify a process ID or a job specification to wait for. man bash :
1 Like
one Idea came into my mind is
pass the parent process id to child and kill parent in child process if child process fails.
correct me if I am doing it in wrong way.
#!/bin/ksh
P_PID=$$
for i in 1 2 3 4 5 6 7 8 9 10
do
child_script $i $P_PID &
done
wait
#!/bin/ksh
some code of child
ret_stat=$?
if [ "$ret_stat" -ne "0" ]
then
kill $2
fi
---------- Post updated at 01:28 AM ---------- Previous update was at 01:27 AM ----------
thanks rudic for quick reply
can you please explain me with example.
With file1 .. file4 existing in PWD, I ran
for i in 1 2 3 4 5; do { sleep $i; ls file$i; } & done; jobs; for i in 1 2 3 4 5; do wait %$i; echo $?; done
[1] 7865
[2] 7866
[3] 7867
[4] 7869
[5] 7870
[1] Running { sleep $i; ls file$i; } &
[2] Running { sleep $i; ls file$i; } &
[3] Running { sleep $i; ls file$i; } &
[4]- Running { sleep $i; ls file$i; } &
[5]+ Running { sleep $i; ls file$i; } &
file1
[1] Done { sleep $i; ls file$i; }
0
file2
[2] Done { sleep $i; ls file$i; }
0
file3
[3] Done { sleep $i; ls file$i; }
0
file4
[4]- Done { sleep $i; ls file$i; }
0
ls: cannot access 'file5': No such file or directory
[5]+ Exit 2 { sleep $i; ls file$i; }
2
1 Like
Thanks for your reply.
I don't want to exit the script if none of child process fails. I want to exit only if my child process fails.
I tried below code snippet more like your solution only.
files="test test2 "
pids=""
exit_counter=0
for i in $files; do
./test2 $i &
p_pid="$!"
echo "$i process id is : $p_pid"
pids+="$p_pid "
done
jobs -p
for pid in $pids; do
wait $pid
if [ $? -eq 0 ]; then
echo "SUCCESS - Job $pid exited with a status of $?"
else
echo "FAILED - Job $pid exited with a status of $?"
exit_counter=`expr "$exit_counter" + 1 `
echo "EXIT COUNTER : $exit_counter"
fi
done
if [ $exit_counter -ne 0 ]
then
exit "$exit_counter"
fi
I see a weakness if the child process fails without terminating.
Examples:
user input required
runaway process.
I would consider replacing the wait process with a loop that executes every 30 (?) seconds to see if all processes have finished, and if not within a reasonable time frame, perform some notification.
Note also that your FAILED notice in:
for pid in $pids; do
wait $pid
if [ $? -eq 0 ]; then
echo "SUCCESS - Job $pid exited with a status of $?"
else
echo "FAILED - Job $pid exited with a status of $?"
exit_counter=`expr "$exit_counter" + 1 `
echo "EXIT COUNTER : $exit_counter"
fi
done
is attributing the exit status of the test command to the job on which you're reporting instead of the exit status of the job. You probably want something more like:
for pid in $pids; do
wait $pid
status=$?
if [ $status -eq 0 ]; then
echo "SUCCESS - Job $pid exited with a status of 0"
else
echo "FAILED - Job $pid exited with a status of $status"
exit_counter=`expr "$exit_counter" + 1 `
echo "EXIT COUNTER : $exit_counter"
fi
done
but, of course, that doesn't get around the problem of wait $pid hanging forever if the job it is waiting for is hung waiting for input or has entered an infinite loop.
echo "begin" >test1
elapsed_time=0
while [ -s test1 ]
do
cat /dev/null >test1
ps -ef |grep $pid1 >test1
ps -ef |grep $pid2 >>test1
#repeat for each process
if [ -s test1 ]
then
sleep 30
let elapsed_time=elapsed_time+30
if [ elapsed_time -gt 300 ]
then
echo "all processes should have finished by now"
cat test1
exit 1
fi
fi
done