package testutil import ( "errors" "fmt" "os/exec" "strings" "github.com/docker/docker/pkg/system" ) func runCommandWithOutput(cmd *exec.Cmd) (output string, exitCode int, err error) { out, err := cmd.CombinedOutput() exitCode = system.ProcessExitCode(err) output = string(out) return } // RunCommandPipelineWithOutput runs the array of commands with the output // of each pipelined with the following (like cmd1 | cmd2 | cmd3 would do). // It returns the final output, the exitCode different from 0 and the error // if something bad happened. func RunCommandPipelineWithOutput(cmds ...*exec.Cmd) (output string, exitCode int, err error) { if len(cmds) < 2 { return "", 0, errors.New("pipeline does not have multiple cmds") } // connect stdin of each cmd to stdout pipe of previous cmd for i, cmd := range cmds { if i > 0 { prevCmd := cmds[i-1] cmd.Stdin, err = prevCmd.StdoutPipe() if err != nil { return "", 0, fmt.Errorf("cannot set stdout pipe for %s: %v", cmd.Path, err) } } } // start all cmds except the last for _, cmd := range cmds[:len(cmds)-1] { if err = cmd.Start(); err != nil { return "", 0, fmt.Errorf("starting %s failed with error: %v", cmd.Path, err) } } defer func() { var pipeErrMsgs []string // wait all cmds except the last to release their resources for _, cmd := range cmds[:len(cmds)-1] { if pipeErr := cmd.Wait(); pipeErr != nil { pipeErrMsgs = append(pipeErrMsgs, fmt.Sprintf("command %s failed with error: %v", cmd.Path, pipeErr)) } } if len(pipeErrMsgs) > 0 && err == nil { err = fmt.Errorf("pipelineError from Wait: %v", strings.Join(pipeErrMsgs, ", ")) } }() // wait on last cmd return runCommandWithOutput(cmds[len(cmds)-1]) }