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https://issues.apache.org/jira/browse/STORM-442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14189530#comment-14189530
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ASF GitHub Bot commented on STORM-442:
--------------------------------------
Github user dashengju commented on the pull request:
https://github.com/apache/storm/pull/218#issuecomment-61038451
@HeartSaVioR ,
parent process's exception contains two types: 1) net io error caused; for
example, subprocess report an error to stderr and exit; 2) parent process's
handle logic exception.
as 1), we want to read from stderr to get more information;
as 2), as you say, it may not be right way to capture it when only parent
process raises exception.
@d2r 's suggestion, we should change ShellProcess#getErrorsStream so that
it checks that there is actually something to read.
> multilang ShellBolt/ShellSpout die() can be hang when Exception happened
> ------------------------------------------------------------------------
>
> Key: STORM-442
> URL: https://issues.apache.org/jira/browse/STORM-442
> Project: Apache Storm
> Issue Type: Bug
> Affects Versions: 0.9.3
> Reporter: DashengJu
>
> In ShellBolt, the _readerThread read command from python/shell process, and
> handle like this:
> try {
> ShellMsg shellMsg = _process.readShellMsg();
> ...
> } catch (InterruptedException e) {
> } catch (Throwable t) {
> die(t);
> }
> And in the die function, getProcessTerminationInfoString will read
> getErrorsString() from processErrorStream.
> private void die(Throwable exception) {
>
> String processInfo = _process.getProcessInfoString() +
> _process.getProcessTerminationInfoString();
>
> _exception = new RuntimeException(processInfo, exception);
>
> }
> so when ShellBolt got exception(for example, readShellMsg() throw NPE ) ,
> but it is not an error from sub process, then
> getProcessTerminationInfoString will be hang because processErrorStream have
> no data to read.
> On the other hand, as [~xiaokang] says ShellBolt should fail fast on
> exception ( https://github.com/apache/incubator-storm/pull/46 ) , I think it
> is not a good idea to read error info from stream.
> Because [~xiaokang] 's PR is based old version, so I will move his code to
> this PR, and modify some other place in ShellSpout.
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