grim/convey

Don't potentially deadlock on commands if we bomb out early with errors

2019-08-02, Gary Kramlich
37db7a19923f
Parents fe6910f8166f
Children ca2b01050753
Don't potentially deadlock on commands if we bomb out early with errors
1 files changed, 7 insertions(+), 4 deletions(-)
  • +7 -4
    command/command.go
    • --- a/command/command.go Fri Aug 02 01:41:21 2019 -0500
    +++ b/command/command.go Fri Aug 02 03:19:39 2019 -0500
    @@ -38,7 +38,7 @@
    errCollector = newLogCollector(logger, log.ErrorLevel)
    )
    - return run(name, cmdv, timeout, outCollector, errCollector)
    + return run(name, cmdv, timeout, &sync.WaitGroup{}, outCollector, errCollector)
    }
    // RunOutput works just like Run but returns stdout and stderr instead of
    @@ -50,14 +50,13 @@
    errCollector = newStringCollector(wg)
    )
    - wg.Add(2)
    - err := run(name, cmdv, timeout, outCollector.handler, errCollector.handler)
    + err := run(name, cmdv, timeout, wg, outCollector.handler, errCollector.handler)
    wg.Wait()
    return outCollector.output, errCollector.output, err
    }
    -func run(name string, cmdv []string, timeout time.Duration, outHandler, errHandler collector) error {
    +func run(name string, cmdv []string, timeout time.Duration, wg *sync.WaitGroup, outHandler, errHandler collector) error {
    logger := logging.NewAdapter(name)
    logger.Debugf("running command \"%v\"", cmdv)
    @@ -76,6 +75,10 @@
    return err
    }
    + // at this point we're committed to running the log handlers so increment
    + // the waitgroup
    + wg.Add(2)
    +
    // Pass output to the handlers
    go outHandler(bufio.NewScanner(outReader))
    go errHandler(bufio.NewScanner(errReader))