github.com/elliott5/community@v0.14.1-0.20160709191136-823126fb026a/wordsmith/utility/command.go (about)

     1  // Copyright 2016 Documize Inc. <legal@documize.com>. All rights reserved.
     2  //
     3  // This software (Documize Community Edition) is licensed under 
     4  // GNU AGPL v3 http://www.gnu.org/licenses/agpl-3.0.en.html
     5  //
     6  // You can operate outside the AGPL restrictions by purchasing
     7  // Documize Enterprise Edition and obtaining a commercial license
     8  // by contacting <sales@documize.com>. 
     9  //
    10  // https://documize.com
    11  
    12  package utility
    13  
    14  import (
    15  	"bytes"
    16  	"github.com/documize/community/wordsmith/log"
    17  	"errors"
    18  	"os/exec"
    19  	"time"
    20  )
    21  
    22  var errTimeout = errors.New("conversion timelimit exceeded")
    23  
    24  // CommandWithTimeout runs a command but stops it if it does not finish within the timout above.
    25  func CommandWithTimeout(command *exec.Cmd, timeout time.Duration) ([]byte, error) {
    26  	var output bytes.Buffer
    27  	//fmt.Println("DEBUG CommandWithTimeout: %v", command.Args)
    28  	command.Stdout = &output
    29  	command.Stderr = &output
    30  	if err := command.Start(); err != nil {
    31  		return nil, err
    32  	}
    33  	done := make(chan error, 1)
    34  	defer close(done)
    35  	go func() {
    36  		done <- command.Wait()
    37  	}()
    38  	select {
    39  	case <-time.After(timeout):
    40  		if err := command.Process.Kill(); err != nil {
    41  			log.Error("failed to kill: ", err)
    42  		}
    43  		<-done // prevent memory leak
    44  		//fmt.Println("DEBUG timeout")
    45  		return nil, errTimeout
    46  	case err := <-done:
    47  		if err != nil {
    48  			//fmt.Println("DEBUG error return")
    49  			return output.Bytes(), err
    50  		}
    51  		if !command.ProcessState.Success() {
    52  			err = errors.New(string(output.Bytes()))
    53  			//fmt.Println("DEBUG not successful")
    54  			return nil, err
    55  		}
    56  		//fmt.Println("DEBUG successful return")
    57  		return output.Bytes(), nil
    58  	}
    59  }