[SPARK-7347] DAG visualization: add tooltips to RDDs

This is an addition to apache#5729.

Here's an example with ALS.
<img src="https://issues.apache.org/jira/secure/attachment/12731039/tooltip.png" width="400px"></img>

Author: Andrew Or <[email protected]>

Closes apache#5957 from andrewor14/viz-hover2 and squashes the following commits:

60e3758 [Andrew Or] Add tooltips for RDDs on job page

Author: Andrew Or

core/src/main/resources/org/apache/spark/ui/static/spark-dag-viz.js

@@ -218,6 +218,7 @@ function renderDagVizForJob(svgContainer) {
     });
   });
 
+  addTooltipsForRDDs(svgContainer);
   drawCrossStageEdges(crossStageEdges, svgContainer);
 }
 
@@ -424,6 +425,21 @@ function connectRDDs(fromRDDId, toRDDId, edgesContainer, svgContainer) {
   edgesContainer.append("path").datum(points).attr("d", line);
 }
 
+/* (Job page only) Helper function to add tooltips for RDDs. */
+function addTooltipsForRDDs(svgContainer) {
+  svgContainer.selectAll("g.node").each(function() {
+    var node = d3.select(this);
+    var tooltipText = node.attr("name");
+    if (tooltipText) {
+      node.select("circle")
+        .attr("data-toggle", "tooltip")
+        .attr("data-placement", "right")
+        .attr("title", tooltipText)
+    }
+  });
+  $("[data-toggle=tooltip]").tooltip({container: "body"});
+}
+
 /* Helper function to convert attributes to numeric values. */
 function toFloat(f) {
   if (f) {

core/src/main/scala/org/apache/spark/ui/scope/RDDOperationGraph.scala

@@ -178,10 +178,11 @@ private[ui] object RDDOperationGraph extends Logging {
    * On the stage page, it is displayed as a box with an embedded label.
    */
   private def makeDotNode(node: RDDOperationNode, forJob: Boolean): String = {
+    val label = s"${node.name} (${node.id})"
     if (forJob) {
-      s"""${node.id} [label=" " shape="circle" padding="5" labelStyle="font-size: 0"]"""
+      s"""${node.id} [label="$label" shape="circle" padding="5" labelStyle="font-size: 0"]"""
     } else {
-      s"""${node.id} [label="${node.name} (${node.id})" padding="5" labelStyle="font-size: 10"]"""
+      s"""${node.id} [label="$label" padding="5" labelStyle="font-size: 10"]"""
     }
   }