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Hadoop >> mail # dev >> [VOTE] introduce Python as build-time and run-time dependency for Hadoop and throughout Hadoop stack

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Re: [VOTE] introduce Python as build-time and run-time dependency for Hadoop and throughout Hadoop stack
+1, +1, +1 (non-binding)

We have had promising results for 1 and 2 when porting to Windows. 3 would
allow us to remove platform dependencies from test code. Agree that there
might be some nuanced operations that require OS specific environments but
this would lead to keeping them at a minimum.


On 11/29/12 7:22 PM, "Chuan Liu" <[EMAIL PROTECTED]> wrote:

>+1 +1 +1
>Agree with Matt on the code maintainability.
>I think on one side we have Shell which is a script language and OS
>dependent, e.g. as in bash vs powershell;
>on the other side we have Java which is not a script language and OS
>I would accept any script language that can fix the gap as an OS
>independent scripting language.
>Personally, I also prefer Python over Ruby.
>From: [EMAIL PROTECTED] on behalf of Matt Foley
>Sent: Thursday, November 29, 2012 6:26 PM
>Subject: Re: [VOTE] introduce Python as build-time and run-time
>dependency for Hadoop and throughout Hadoop stack
>Hello again.  Crossed in the mail.
>* What kind of tasks you envision Python scripts will enable that are
>> not possible today?
>The point isn't to open brave new worlds.  The point is to avoid the
>nightmare of having to maintain multiple "parallel" scripts doing the SAME
>THING in multiple scripting languages.  I know from experience that they
>never get maintained right.  It's just a huge source of bugs, because when
>they are in different languages, it can be quite difficult to determine
>that they are *really* doing the same thing.  And in a case like shell vs
>powershell, it will be very common to have contributors who are not
>in both.
>I care deeply about having a high-quality release in both Linux and
>Windows.  And having a cross-platform scripting language will make it much
>easier to maintain that quality over time, without "slip" between the two
>* Will the requirement of Python be pushed to clients using the
>> hadoop script? If so, this would affect all downstream projects that use
>> hadoop script in one why or the other, right?
>If question #3 passes, then Python will become a run-time dependency for
>Hadoop.  That means it would need to be installed as part of the Hadoop
>install preparation, just like all the other Hadoop run-time dependencies.
>Is the main motivation of the proposal to make things easier for window,
>> so there is no need for cygwin? If that is the case, have you considered
>> doing directly BAT scripts? If you take Tomcat for example, they have
>> scripts and SH scripts and things work quite nicely.
>Of course it is sufficient, from the simple implementation perspective, to
>translate all the shell scripts into bat or (better) powershell scripts.
> That is, in fact, the most evident alternative to my proposals #1 and #3.
>However, I ask -- beg! -- the community to consider it from the software
>engineering perspective.  We aren't here to just implement something once
>and be done.  It has to be maintained, as most of you on this list are
>aware, for years and years, across multiple generations.  And trying to
>maintain parallel scripts in multiple languages, when not necessitated by
>genuine platform-specific requirements, is just creating bug generators in
>the system.
>Personally, I wouldn't be trilled to see the logic in the scripts to
>> get more complex, but on the opposite direction; IMO, scripts should be
>> trimmed to set env vars (with no voodoo logic), build the classpath
>> no voodoo logic, just from a set of dirs) and call Java.
>See the first item above.  The point is to enable cross-platform scripting
>of the things we already have to script.  IMO, scripts should get out of
>the env var business entirely, but that's unrelated to this question :-)
>Finally, this is code change, so I'm not sure why we are doing a vote.
>I view this as a tools issue, that affects questions that go beyond the