[jira] [Resolved] (NIFI-5024) Deadlock in ExecuteStreamCommand processor

["Mike Thomsen (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/NIFI-5024?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Mike Thomsen resolved NIFI-5024.
--------------------------------
       Resolution: Fixed
    Fix Version/s: 1.7.0

> Deadlock in ExecuteStreamCommand processor
> ------------------------------------------
>
>                 Key: NIFI-5024
>                 URL: https://issues.apache.org/jira/browse/NIFI-5024
>             Project: Apache NiFi
>          Issue Type: Bug
>    Affects Versions: 1.3.0
>            Reporter: Nicolas Sanglard
>            Priority: Minor
>             Fix For: 1.7.0
>
>         Attachments: Screen Shot 2018-03-28 at 15.34.36.png, Screen Shot 2018-03-28 at 15.36.02.png
>
>
> Whenever a process is producing too much output on stderr, the current implementation will run into a deadlock between the JVM and the unix process started by the ExecuteStreamCommand.
> This is a known issue that is fully described here: [http://java-monitor.com/forum/showthread.php?t=4067]
> In short:
>  * If the process produces too much stderr that is not consumed by ExecuteStreamCommand, it will block until data is read.
>  * The current processor implementation is reading from stderr only after having called process.waitFor()
>  * Thus, the two processes are waiting for each other and fall into a deadlock
>  
>  
> The following setup will lead to a deadlock:
>  
> A jar containing the following Main application:
> {code:java}
> object Main extends App {
>   import scala.collection.JavaConverters._
>   val str = Source.fromInputStream(this.getClass.getResourceAsStream("/1mb.txt")).mkString
>   System.err.println(str)
> }
> {code}
> The following NiFi Flow:
>  
> !Screen Shot 2018-03-28 at 15.34.36.png!
>  
> Configuration for ExecuteStreamCommand:
>  
> !Screen Shot 2018-03-28 at 15.36.02.png!
>  
> The script is simply containing a call to the jar: 
> {code:java}
> java -jar stderr.jar
> {code}
>  
> Once the processor calls the script, it appears as "processing" indefinitely and can only be stopped by restarting NiFi.
>  
> I already have a running solution that I will publish as soon as possible.
>  



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