[SPARK-20646][core] Port executors page to new UI backend.

[vanzin]

The executors page is built on top of the REST API, so the page itself
was easy to hook up to the new code.

Some other pages depend on the ExecutorListener class that is being
removed, though, so they needed to be modified to use data from the
new store. Fortunately, all they seemed to need is the map of executor
logs, so that was somewhat easy too.

The executor timeline graph required adding some properties to the
ExecutorSummary API type. Instead of following the previous code,
which stored all the listener events in memory, the timeline is
now created based on the data available from the API.

I had to change some of the test golden files because the old code would
return executors in "random" order (since it used a mutable Map instead
of something that returns a sorted list), and the new code returns executors
in id order.

Tested with existing unit tests.

[vanzin]

For context:

• Project link: https://issues.apache.org/jira/browse/SPARK-18085
• Upcoming PRs that build on this code: https://github.com/vanzin/spark/pulls
• PR with more comments: SHS-NG M4.2: Port executors page to new backend. vanzin/spark#45

[SparkQA]

Test build #83505 has finished for PR 19678 at commit f88163a.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[squito]

lgtm

a couple nits about unused imports -- there are some more in AppStatusStore, SparkUI as well (probably from before) would be nice to clean them up.

[squito]

nit: I think more of these imports can be deleted

[squito]

nit: this import is no longer used

[squito]

Also going to copy this comment from here for others: vanzin#45

squito 12 days ago
what do you think about adding a helper method for these json snippets? obviously not the fault of your change, but I find these so hard to read, eg. figuring out where data-title ends (worse in some of the other cases esp in StagePage). something like

UIUtils.timelineJsonEvent(
  className="executor added",
  group="executors",
  start = e.addTime.getTime(),
  end = None,
  contentClass = "executor-event-content",
  dataTitle = s"Executor ${e.id}<br> Added at ${UIUtils.formatDate(new Date(e.addTime.getTime()))}",
  contentBody = s"Executor ${e.id} added")

vanzin 11 days ago Owner
I'm not against it but I'd rather do that separately.

agree, fine to do that later.

[SparkQA]

Test build #83556 has finished for PR 19678 at commit e4c427a.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[squito]

lgtm
(assuming tests pass)

[SparkQA]

Test build #83568 has started for PR 19678 at commit c7123d9.

[vanzin]

retest this please

[SparkQA]

Test build #83572 has finished for PR 19678 at commit c7123d9.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[squito]

merged to master