Execute a shell function with timeout

Question

Why would this work  timeout 10s echo  foo bar    foo bar   but this wouldn t  function echoFooBar     echo  foo bar     echoFooBar   foo bar  timeout 10s echoFooBar   timeout  failed to run command  echoFooBar   No such file or directory   and how can I make it work

User · Answer

You can create a function which would allow you to do the same as timeout but also for other functions:

function run_cmd { 
    cmd="$1"; timeout="$2";
    grep -qP '^\d+$' <<< $timeout || timeout=10

    ( 
        eval "$cmd" &
        child=$!
        trap -- "" SIGTERM 
        (       
                sleep $timeout
                kill $child 2> /dev/null 
        ) &     
        wait $child
    )
}

And could run as below:

run_cmd "echoFooBar" 10

Note: The solution came from one of my questions: Elegant solution to implement timeout for bash commands and functions

User · Answer

Putting my comment to Tiago Lopo s answer into more readable form   I think it s more readable to impose a timeout on the most recent subshell  this way we don t need to eval a string and the whole script can be highlighted as shell by your favourite editor  I simply put the commands after the subshell with eval has spawned into a shell-function  tested with zsh  but should work with bash     timeout child          trap --    SIGTERM     child        timeout  1                   sleep  timeout             kill  child        amp      wait  child     Example usage     while true  do echo -n    sleep 0 1  done   amp  timeout child 2  And this way it also works with a shell function  if it runs in the background     print dots           while true      do          sleep 0 1          echo -n        done        gt  print dots  amp  timeout child 2   1  21725   3  21727                      1     21725 terminated  print dots   3     21727 done         sleep  timeout  kill  child

User · Answer

if you just want to add timeout as an additional option for the entire existing script  you can make it test for the timeout-option  and then make it call it self recursively without that option   example sh      bin bash if     1      -t     then   timeout 1m  0  2 else    the original script   echo  1   sleep 2m   echo YAWN    fi   running this script without timeout      example sh -other option   -other option                               YAWN      running it with a one minute timeout      example sh -t -other option   -other option

User · Answer

function foo        for i in  1  100       do          echo  i            sleep 1      done     cat  lt   foo     Will work  timeout 3 cat  lt   foo     Will Work  timeout 3 cat  lt   foo     sort   Wont work  As sort will fail  cat  lt   timeout 3 cat  lt   foo       sort -r   Will Work

User · Answer

There s an inline alternative also launching a subprocess of bash shell     timeout 10s bash  lt  lt EOT function echoFooBar     echo foo    echoFooBar sleep 20 EOT

User · Answer

I have a slight modification of  Tiago Lopo s answer that can handle commands with multiple arguments  I ve also tested TauPan s solution  but it does not work if you use it multiple times in a script  while Tiago s does   function timeout cmd      local arr   local cmd   local timeout    arr               timeout  first arg     cmd  the other args   timeout    arr 0      cmd      arr    1               eval    cmd       amp      child         echo  child   child      trap --    SIGTERM                     sleep   timeout        kill   child  2 gt   dev null         amp           wait   child          Here s a fully functional script thant you can use to test the function above       test timeout sh -h Usage    test timeout sh  -n   -r REPEAT   -s SLEEP TIME   -t TIMEOUT    test timeout sh -h  Test timeout cmd function   Options    -n              Dry run  do not actually sleep     -r REPEAT       Reapeat everything multiple times  default  1     -s SLEEP TIME   Sleep for SLEEP TIME seconds  default  5     -t TIMEOUT      Timeout after TIMEOUT seconds  default  no timeout     For example you cnal launch like this       test timeout sh -r 2 -s 5 -t 3 Try no  1   - Set timeout to  3 child  2540     - gt  retval  143     - gt  The command timed out Try no  2   - Set timeout to  3 child  2593     - gt  retval  143     - gt  The command timed out Done       usr bin env bash   shellcheck disable SC2128 SOURCED false  amp  amp      0      BASH SOURCE       SOURCED true  if    SOURCED  then   set -euo pipefail   IFS    n t  fi                       helpers function check posint       local re    0-9       local mynum   1    local option   2     if        mynum      re      then       echo -n  Error in option   option      gt  amp 2        echo  must be a positive integer  got  mynum    gt  amp 2       exit 1   fi    if       mynum  -gt 0     then       echo  Error in option   option   must be positive  got  mynum    gt  amp 2       exit 1   fi                        end  helpers                       usage function short usage         gt  amp 2 echo    Usage    test timeout sh  -n   -r REPEAT   -s SLEEP TIME   -t TIMEOUT    test timeout sh -h         function usage         gt  amp 2 short usage       gt  amp 2 echo     Test timeout cmd function   Options    -n              Dry run  do not actually sleep     -r REPEAT       Reapeat everything multiple times  default  1     -s SLEEP TIME   Sleep for SLEEP TIME seconds  default  5     -t TIMEOUT      Timeout after TIMEOUT seconds  default  no timeout                             end  usage  help flag false dryrun flag false SLEEP TIME 5 TIMEOUT -1 REPEAT 1  while getopts   hnr s t   opt  do   case  opt in     h        help flag true                  n        dryrun flag true              r        check posint   OPTARG   -r         REPEAT   OPTARG               s        check posint   OPTARG   -s         SLEEP TIME   OPTARG               t        check posint   OPTARG   -t         TIMEOUT   OPTARG                           gt  amp 2 echo  Error  Invalid option  - OPTARG            gt  amp 2 echo  Try -h to get help         short usage       exit 1                         gt  amp 2 echo  Error Option - OPTARG requires an argument            gt  amp 2 echo  Try -h to get help         short usage       exit 1            esac done  if  help flag  then   usage   exit 0 fi                       utils if  dryrun flag  then   function wrap run           echo -en   dry run   t          echo            else   function wrap run             fi    Execute a shell function with timeout   https   stackoverflow com a 24416732 2377454 function timeout cmd      local arr   local cmd   local timeout    arr               timeout  first arg     cmd  the other args   timeout    arr 0      cmd      arr    1               eval    cmd       amp      child         echo  child   child      trap --    SIGTERM                     sleep   timeout        kill   child  2 gt   dev null         amp           wait   child                              function sleep func       local secs   local waitsec    waitsec 1   secs     1     while     secs  -gt 0    do    echo -ne   secs 033 0K r     sleep   waitsec     secs    secs-waitsec     done     command   wrap run              sleep func     SLEEP TIME               for i in   seq 1   REPEAT    do   echo  Try no   i     if     TIMEOUT  -gt 0    then     echo    - Set timeout to   TIMEOUT      set  e     timeout cmd   TIMEOUT     command          retval          set -e      echo      - gt  retval   retval        check if  retval   128     SIGTERM     15      if        retval   128    -eq 15     then       echo      - gt  The command timed out      fi   else     echo    - No timeout         command          retval        fi done  echo  Done    exit 0

User · Answer

As Douglas Leeder said you need a separate process for timeout to signal to  Workaround by exporting function to subshells and running subshell manually   export -f echoFooBar timeout 10s bash -c echoFooBar

User · Answer

This one liner will exit your Bash session after 10s    TMOUT 10  amp  amp  echo  foo bar

User · Answer

This function uses only builtins   Maybe consider evaling      instead of running    directly depending on your needs It starts a job with the command string specified after the first arg that is the timeout value and monitors the job pid It checks every 1 seconds  bash supports timeouts down to 0 01 so that can be tweaked Also if your script needs stdin  read should rely on a dedicated fd  exec  tofd  lt  gt   lt      Also you might want to tweak the kill signal  the one inside the loop  which is default to -15  you might want -9        forking is evil timeout         to  1  shift         amp  local wp    start 0      while kill -0  wp  do         read -t 1         start    start 1           if    start -ge  to    then             kill  wp  amp  amp  break         fi     done

User · Answer

timeout is a command - so it is executing in a subprocess of your bash shell  Therefore it has no access to your functions defined in your current shell   The command timeout is given is executed as a subprocess of timeout - a grand-child process of your shell   You might be confused because echo is both a shell built-in and a separate command   What you can do is put your function in it s own script file  chmod it to be executable  then execute it with timeout   Alternatively fork  executing your function in a sub-shell - and in the original process  monitor the progress  killing the subprocess if it takes too long

[bash] Execute a shell function with timeout

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