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From Himanish Kushary <himan...@gmail.com>
Subject Re: Getting last action node id from within another action node
Date Sat, 01 Sep 2012 00:59:29 GMT
Hi Mona,

Thanks for your reply.Here is more details on my usecase.

I am running a hive action ( the SQL calculates the count for a
table(table1) joined with two other tables)  to update a directory in HDFS(
only with the count in the generated file), then using a Java action I am
generating the reading that count from the HDFS file and if the count is
greater than zero, I am setting a property proceed=1.In the decision action
node, if  proceed=1 then fail else move on to next hive action.

Now incidentally my next hive action is also similar ( means it also
calculates count by joining the table table1 with few other tables) and
will follow the same Java action --> Decision Node logic as above.

Now to keep the workflow xml simple and avoid duplicating the same set of
(action node - java action node - decision node).. in the decision node i
will like to use a logic like(in the switch case) :
case
when( proceed!=1 and wf.lastActionName='hive1') then move to 'hive2'
when( proceed!=1 and wf.lastActionName='hive2') then move to 'hive3'
when( proceed!=1 and wf.lastActionName='hive3') then move to 'hive4'

Thats why I was looking for something in that line.Not sure whether I am
making things far too complicated :-)

Hope this helps to give a better understanding of what I am trying
to achieve.

Thanks
Himanish

On Fri, Aug 31, 2012 at 3:48 PM, Mona Chitnis <chitnis@yahoo-inc.com> wrote:

> Hi Himanish,
>
> There are a couple of other alternatives to this as well. Say if either of
> your preceding actions A or AA is a
>
>  *   java action, using <capture-output> tag, you will get all the
> action's data, accessible via wf:actionData(actionNode)
>
>
> http://incubator.apache.org/oozie/docs/3.2.0-incubating/docs/WorkflowFunctionalSpec.html#a4.2.1_Basic_EL_Constants
>
>  *   Map-reduce action, you can access mr counters (hadoop EL functions)
> of that node, and retrieve the information about this node
>
>
> http://incubator.apache.org/oozie/docs/3.2.0-incubating/docs/WorkflowFunctionalSpec.html#a4.2.5_Hadoop_EL_Functions
>
>
> Maybe you can elaborate on this use-case a bit more? We can think about
> supporting it if the current options are not solving it in entirety.
>
> Thanks and Regards,
> --
> Mona Chitnis
>
>
>
> On 8/31/12 11:09 AM, "Mona Chitnis" <chitnis@yahoo-inc.com<mailto:
> chitnis@yahoo-inc.com>> wrote:
>
> Hi Himanish,
>
> I believe the EL function that would be of use in this case is
> wf:transition(String node). You can check through the various action nodes
> preceding your java action (say called "java-node"), to check which holds
> the value "java-node" as a transition. Once you have that answer, is your
> Java action code handling it in some way to put it in the output
> properties? Or you could make this comparison as part of your decision
> node switch-case too.
>
> Hope that helps,
> --
> Mona Chitnis
>
>
>
>
> On 8/31/12 7:27 AM, "Himanish Kushary" <himanish@gmail.com<mailto:
> himanish@gmail.com>> wrote:
>
> Hi
>
> I am trying to define a workflow where I could come into a java action
> node
> from either Action A or Action AA.Depending on whether I come from Action
> A
> or Action AA I would like to write different values into the properties
> file (capture-output) that will be generated from the java action.
> Subsequently a decision node will take different route based on the
> different properties (key-value) set through the java action.I was
> thinking
> of implementing the different properties key using the action id for
> Action
> A / Action AA.
>
> Is there any way to know the previous action id from the Java action
> Node.Is there any EL function like wf:lastActionId ? Is there any
> alternative way to define similar workflow ?
>
>
> <action A> ----------
>                            ------------------- <action B>
>                            |------------ <java action node>
> ----------<decision node 1>--|
> <action AA>---------
>                            ------------------ <action BB>
>
>
> ---------------------------
> Thanks & Regards
> Himanish
>
>
>


-- 
Thanks & Regards
Himanish

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