Add event-flow visualization (#3102)

* [event-flow] add event flow visualizaton type from @data-ui/event-flow.

* [event-flow] update vis thumbnail

* [event-flow] update row limit label, remove duplicate chart controls

* [dependencies] add @data-ui/event-flow 0.0.2

* [linting] fix multiple imports

* [deps] bump mapbox-gl and react-map-gl to fix build

* [event-flow] bump to 0.0.3 for es2015 + stage-0 babel presets

* [deps] revert mapbox version bumps

* [event-flow] update png, bump to newest version, address reviewer comments, add min event count form.

* [event-flow] pin version

* [event-flow][spec] add test for coveralls

* [event-flow] revert spec

superset/assets/javascripts/explore/stores/controls.jsx

@@ -659,7 +659,7 @@ export const controls = {
     label: 'Entity',
     default: null,
     validators: [v.nonEmpty],
-    description: 'This define the element to be plotted on the chart',
+    description: 'This defines the element to be plotted on the chart',
     mapStateToProps: state => ({
       choices: (state.datasource) ? state.datasource.gb_cols : [],
     }),
@@ -1273,5 +1273,23 @@ export const controls = {
     hidden: true,
     description: 'The number of seconds before expiring the cache',
   },
+
+  order_by_entity: {
+    type: 'CheckboxControl',
+    label: 'Order by entity id',
+    description: 'Important! Select this if the table is not already sorted by entity id, ' +
+    'else there is no guarantee that all events for each entity are returned.',
+    default: true,
+  },
+
+  min_leaf_node_event_count: {
+    type: 'SelectControl',
+    freeForm: false,
+    label: 'Minimum leaf node event count',
+    default: 1,
+    choices: formatSelectOptionsForRange(1, 10),
+    description: 'Leaf nodes that represent fewer than this number of events will be initially ' +
+    'hidden in the visualization',
+  },
 };
 export default controls;

superset/assets/javascripts/explore/stores/visTypes.js

@@ -1,5 +1,4 @@
 import { D3_TIME_FORMAT_OPTIONS } from './controls';
-
 import * as v from '../validators';
 
 export const sections = {
@@ -890,6 +889,51 @@ const visTypes = {
       },
     },
   },
+
+  event_flow: {
+    label: 'Event flow',
+    requiresTime: true,
+    controlPanelSections: [
+      {
+        label: 'Event definition',
+        controlSetRows: [
+          ['entity'],
+          ['all_columns_x'],
+          ['row_limit'],
+          ['order_by_entity'],
+          ['min_leaf_node_event_count'],
+        ],
+      },
+      {
+        label: 'Additional meta data',
+        controlSetRows: [
+          ['all_columns'],
+        ],
+      },
+    ],
+    controlOverrides: {
+      entity: {
+        label: 'Column containing entity ids',
+        description: 'e.g., a "user id" column',
+      },
+      all_columns_x: {
+        label: 'Column containing event names',
+        validators: [v.nonEmpty],
+        default: control => (
+          control.choices && control.choices.length > 0 ?
+            control.choices[0][0] : null
+        ),
+      },
+      row_limit: {
+        label: 'Event count limit',
+        description: 'The maximum number of events to return, equivalent to number of rows',
+      },
+      all_columns: {
+        label: 'Meta data',
+        description: 'Select any columns for meta data inspection',
+      },
+    },
+  },
 };
 
 export default visTypes;