SPARK-1469: Scheduler mode should accept lower-case definitions and have...

[techaddict]

... nicer error messages

There are two improvements to Scheduler Mode:

1. Made the built in ones case insensitive (fair/FAIR, fifo/FIFO).
2. If an invalid mode is given we should print a better error message.

[AmplabJenkins]

Can one of the admins verify this patch?

[techaddict]

@pwendell can you review this ?

[pwendell]

This is a good start, but if you look at the JIRA, this exception won't actually echo back to the user the name they provided, which is bad form. I think you should capture the argument the user provided first then echo it back to them:

private val schedulingModeConf = conf.get("spark.scheduler.mode", "FIFO")
val schedulingMode: SchedulingMode = try {
SchedulingMode.withName(schedulingModeConf).toUpperCase)
} catch {
case e: java.util.NoSuchElementException =>
throw new SparkException(s"unrecognized spark.scheduler.mode: $schedulingModeConf")
}

Don't even bother re-sending the NoSuchElementException... it doesn't convey anything useful to the user.

[pwendell]

Jenkins, test this please.

[AmplabJenkins]

Merged build triggered.

[AmplabJenkins]

Merged build started.

[AmplabJenkins]

Merged build finished. All automated tests passed.

[AmplabJenkins]

All automated tests passed.
Refer to this link for build results: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/14177/

[pwendell]

Cool - thanks for this!

[pwendell]

I've merged this.