Add support for timelion:min_interval (#11476)

* Add support for timelion:min_interval

* import -> require

src/core_plugins/timelion/public/lib/_tests_/calculate_interval.js

@@ -0,0 +1,44 @@
+const filename = require('path').basename(__filename);
+const fn = require(`../calculate_interval`);
+const moment = require('moment');
+const expect = require('chai').expect;
+
+
+const from = (count, unit) => moment().subtract(count, unit).valueOf();
+const to = moment().valueOf();
+const size = 200;
+const min = '1ms';
+
+describe(filename, () => {
+  it('Exports a function', () => {
+    expect(fn).to.be.a('function');
+  });
+
+  it('Only calculates when interval = auto', () => {
+    const partialFn = (interval) => fn(from(1, 'y'), to, size, interval, min);
+    expect(partialFn('1ms')).to.equal('1ms');
+    expect(partialFn('bag_of_beans')).to.equal('bag_of_beans');
+    expect(partialFn('auto')).to.not.equal('auto');
+  });
+
+  it('Calculates nice round intervals', () => {
+    const partialFn = (count, unit) => fn(from(count, unit), to, size, 'auto', min);
+    expect(partialFn(15, 'm')).to.equal('1s');
+    expect(partialFn(1, 'h')).to.equal('30s');
+    expect(partialFn(3, 'd')).to.equal('30m');
+    expect(partialFn(1, 'w')).to.equal('1h');
+    expect(partialFn(1, 'y')).to.equal('24h');
+    expect(partialFn(100, 'y')).to.equal('1y');
+  });
+
+  it('Does not calculate an interval lower than the minimum', () => {
+    const partialFn = (count, unit) => fn(from(count, unit), to, size, 'auto', '1m');
+    expect(partialFn(5, 's')).to.equal('1m');
+    expect(partialFn(15, 'm')).to.equal('1m');
+    expect(partialFn(1, 'h')).to.equal('1m');
+    expect(partialFn(3, 'd')).to.equal('30m');
+    expect(partialFn(1, 'w')).to.equal('1h');
+    expect(partialFn(1, 'y')).to.equal('24h');
+    expect(partialFn(100, 'y')).to.equal('1y');
+  });
+});

src/core_plugins/timelion/public/lib/calculate_interval.js

@@ -1,6 +1,10 @@
-module.exports = function calculateInterval(from, to, size, interval) {
+const toMS = require('../../server/lib/to_milliseconds.js');
+
+module.exports = function calculateInterval(from, to, size, interval, min) {
   if (interval !== 'auto') return interval;
-  return roundInterval((to - from) / size);
+  const dateMathInterval = roundInterval((to - from) / size);
+  if (toMS(dateMathInterval) < toMS(min)) return min;
+  return dateMathInterval;
 };
 
 // Totally cribbed this from Kibana 3.

src/core_plugins/timelion/public/panels/timechart/schema.js

@@ -187,7 +187,8 @@ module.exports = function timechartFn(Private, config, $rootScope, timefilter, $
             time.min.valueOf(),
             time.max.valueOf(),
             config.get('timelion:target_buckets') || 200,
-            $scope.interval
+            $scope.interval,
+            config.get('timelion:min_interval') || '1ms',
           );
           const format = getxAxisFormatter(interval);
 

src/core_plugins/timelion/server/handlers/chain_runner.js

@@ -169,7 +169,8 @@ module.exports = function (tlConfig) {
       tlConfig.time.from,
       tlConfig.time.to,
       tlConfig.settings['timelion:target_buckets'] || 200,
-      tlConfig.time.interval
+      tlConfig.time.interval,
+      tlConfig.settings['timelion:min_interval']  || '1ms',
     );
 
     tlConfig.setTargetSeries();

src/core_plugins/timelion/timelion.json

@@ -12,5 +12,6 @@
   "default_rows": 2,
   "default_columns": 2,
   "max_buckets": 2000,
-  "target_buckets": 200
+  "target_buckets": 200,
+  "min_interval": "1ms"
 }

src/ui/settings/defaults.js

@@ -297,6 +297,10 @@ export default function defaultSettingsProvider() {
       value: 2,
       description: 'Number of rows on a timelion sheet by default'
     },
+    'timelion:min_interval': {
+      value: '1ms',
+      description: 'The smallest interval that will be calculated when using "auto"'
+    },
     'timelion:graphite.url': {
       value: 'https://www.hostedgraphite.com/UID/ACCESS_KEY/graphite',
       description: '<em>[experimental]</em> The URL of your graphite host'