[jira] [Commented] (JENA-1219) fuseki init script problems - FUSEKI_USER doesn't work - shell quoting wonky

["Dan Pritts (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-1219?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15402474#comment-15402474 ] 

Dan Pritts commented on JENA-1219:
----------------------------------

I thought that the whole point of the {{disown}} command was to disassociate the child from the parent.   So it seems redundant to me to have that and the exec.    Given the unusual nature of doing 'exec foo &' might I suggest that you add a comment, explaining the intent?

Regardless, though, I mostly don't care, as long as it works.  It didn't, for me; as shipped, so i started poking at it and found it difficult to understand what was going on.  Part of the problem was extraneous double quoting due to the {{log_daemon_msg}} issue, but it still doesn't work.

I grabbed the latest script from git and my current problem is:

{noformat}
[2016-08-01 13:06:40] Server     ERROR Can't find resourceBase (tried webapp, src/main/webapp, /home/fuseki/./webapp and /home/fuseki/./src/main/webapp)
[2016-08-01 13:06:40] Server     ERROR Failed to start
{noformat}

I believe this is because a {{su -}} shell starts in the user's home directory, rather than the current directory, and {{RUN_CMD}} doesn't specify the full path to the software.  

Inspecting the java source I see a comment that FUSEKI_HOME can't be used to find this resource base because the variable hasn't been initialized yet.  https://github.com/apache/jena/blob/master/jena-fuseki2/jena-fuseki-core/src/main/java/org/apache/jena/fuseki/jetty/JettyFuseki.java

I'm attaching sh -x output, the full log file, and /etc/default/fuseki contents.  

I'm not sure of the proper solution.  cd to FUSEKI_HOME in the su'd shell?  

> fuseki init script problems - FUSEKI_USER doesn't work - shell quoting wonky
> ----------------------------------------------------------------------------
>
>                 Key: JENA-1219
>                 URL: https://issues.apache.org/jira/browse/JENA-1219
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: Fuseki
>    Affects Versions: Fuseki 2.3.1
>         Environment: RHEL 6
>            Reporter: Dan Pritts
>            Priority: Minor
>
> another init script issue. 
> If FUSEKI_USER is defined, the script attempts to su to that user.  Here's the original code snippet.
> {noformat}
>       su - "$FUSEKI_USER" -c "
>         log_daemon_msg "Redirecting Fuseki stderr/stdout to $FUSEKI_LOGS_STDERROUT"
>         exec ${RUN_CMD[*]} &> '$FUSEKI_LOGS_STDERROUT' &
>         disown \$!
>         echo \$! > '$FUSEKI_PID'"
> {noformat}
> There are several problems with this.
> 0) log_daemon_msg doesn't exist in this subshell so it throws an error.  I filed a separate bug about this.
> 1) the quoting is problematic, so as written, it doesn't successfully start the software.  
> I think what happens is that the double-quote before the word "Redirecting" closes out the argument to -c
> then the exec happens, but the FUSEKI_LOGS_STDERROROUT is not expanded because it's inside single quotes.  So no log,  or possibly there's a file sitting somewhere called literally $FUSEKI_LOGS_STDERROROUT - but only if the FUSEKI_USER has permissions to write in the current directory.  
> Without the log file, I'm not sure why it doesn't start properly, i didn't troubleshoot further down this path.  
> 2) Normally if you "exec" something, the exec'd program *replaces* the running process.  Since the script has the & to background the process, it does that instead.  Weird.  It's counter-intuitive, though, and unless there's a good reason to have the exec I would suggest removing it.  It seems like the subshell + background + disown should provide the functionality that you would normally expect from exec.  
> I would suggest the following, but I'm not entirely sure of the design goal behind the code snippet so i am not sure it meets the needs.  
> {noformat}
>       su "$FUSEKI_USER" -c "
>         echo Redirecting Fuseki stderr/stdout to $FUSEKI_LOGS_STDERROUT
>         ${RUN_CMD[*]} &> $FUSEKI_LOGS_STDERROUT &
>         disown \$!
>         echo \$! > $FUSEKI_PID "
> {noformat}



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