✨ Builds system load usage widget

docs/widgets.md

@@ -17,6 +17,8 @@ Dashy has support for displaying dynamic content in the form of widgets. There a
   - [Joke of the Day](#joke)
   - [Flight Data](#flight-data)
 - [Self-Hosted Services Widgets](#dynamic-widgets)
+  - [CPU History](#cpu-history-netdata)
+  - [System Load History](#load-history-netdata)
 - [Dynamic Widgets](#dynamic-widgets)
   - [Iframe Widget](#iframe-widget)
   - [HTML Embed Widget](#html-embedded-widget)
@@ -388,6 +390,26 @@ Pull recent CPU usage history from NetData.
   host: http://192.168.1.1:19999
 ```
 
+### Load History (NetData)
+
+Pull recent load usage in 1, 5 and 15 minute intervals, from NetData.
+
+<p align="center"><img width="400" src="https://i.ibb.co/qR9C2tJ/nd-load-history.png" /></p>
+
+##### Options
+
+**Field** | **Type** | **Required** | **Description**
+--- | --- | --- | ---
+**`host`** | `string` |  Required | The URL to your NetData instance
+
+##### Example 
+
+```yaml
+- type: nd-load-history
+  options:
+  host: http://192.168.1.1:19999
+```
+
 ---
 
 ## Dynamic Widgets

src/components/Widgets/NdLoadHistory.vue

@@ -0,0 +1,144 @@
+<template>
+<div class="load-history-chart" :id="chartId"></div>
+</template>
+
+<script>
+import axios from 'axios';
+import { Chart } from 'frappe-charts/dist/frappe-charts.min.esm';
+import WidgetMixin from '@/mixins/WidgetMixin';
+
+export default {
+  mixins: [WidgetMixin],
+  components: {},
+  data() {
+    return {
+      chartTitle: null,
+      chartData: null,
+      chartDom: null,
+    };
+  },
+  mounted() {
+    this.fetchData();
+  },
+  computed: {
+    /* URL where NetData is hosted */
+    netDataHost() {
+      const usersChoice = this.options.host;
+      if (!usersChoice || typeof usersChoice !== 'string') {
+        this.error('Host parameter is required');
+        return '';
+      }
+      return usersChoice;
+    },
+    apiVersion() {
+      return this.options.apiVersion || 'v1';
+    },
+    endpoint() {
+      return `${this.netDataHost}/api/${this.apiVersion}/data?chart=system.cpu`;
+    },
+    /* A sudo-random ID for the chart DOM element */
+    chartId() {
+      return `cpu-history-chart-${Math.round(Math.random() * 10000)}`;
+    },
+    chartHeight() {
+      return this.options.chartHeight || 300;
+    },
+    getChartColor() {
+      const cssVars = getComputedStyle(document.documentElement);
+      return cssVars.getPropertyValue('--widget-text-color').trim() || '#7cd6fd';
+    },
+  },
+  methods: {
+    /* Make GET request to NetData */
+    fetchData() {
+      axios.get(this.endpoint)
+        .then((response) => {
+          this.processData(response.data);
+        })
+        .catch((dataFetchError) => {
+          this.error('Unable to fetch data', dataFetchError);
+        })
+        .finally(() => {
+          this.finishLoading();
+        });
+    },
+    /* Assign data variables to the returned data */
+    processData(data) {
+      const timeData = [];
+      const load1min = [];
+      const load5mins = [];
+      const load15mins = [];
+      data.data.reverse().forEach((reading) => {
+        timeData.push(this.formatDate(reading[0]));
+        load1min.push(reading[1]);
+        load5mins.push(reading[2]);
+        load15mins.push(reading[3]);
+      });
+      this.chartData = {
+        labels: timeData,
+        datasets: [
+          { name: '1 Min', type: 'bar', values: load1min },
+          { name: '5 Mins', type: 'bar', values: load5mins },
+          { name: '15 Mins', type: 'bar', values: load15mins },
+        ],
+      };
+      this.chartTitle = this.makeChartTitle(data.data);
+      this.renderChart();
+    },
+    makeChartTitle(data) {
+      if (!data || !data[0][0]) return '';
+      const diff = Math.round((data[data.length - 1][0] - data[0][0]) / 60);
+      return `Past ${diff} minutes`;
+    },
+    renderChart() {
+      this.chartDom = this.generateChart();
+    },
+    /* Create new chart, using the crypto data */
+    generateChart() {
+      return new Chart(`#${this.chartId}`, {
+        title: this.chartTitle,
+        data: this.chartData,
+        type: 'axis-mixed',
+        height: this.chartHeight,
+        colors: [this.getChartColor, '#743ee2'],
+        truncateLegends: true,
+        lineOptions: {
+          regionFill: 1,
+          hideDots: 1,
+        },
+        axisOptions: {
+          xIsSeries: true,
+          xAxisMode: 'tick',
+        },
+        tooltipOptions: {
+          formatTooltipY: d => `${Math.round(d)}%`,
+        },
+      });
+    },
+    /* Format the date for a given time stamp, also include time if required */
+    formatDate(timestamp) {
+      const localFormat = navigator.language;
+      const dateFormat = { weekday: 'short', day: 'numeric', month: 'short' };
+      const timeFormat = { hour: 'numeric', minute: 'numeric', second: 'numeric' };
+      const date = new Date(timestamp * 1000).toLocaleDateString(localFormat, dateFormat);
+      const time = Intl.DateTimeFormat(localFormat, timeFormat).format(timestamp);
+      return `${date} ${time}`;
+    },
+  },
+};
+</script>
+
+<style lang="scss">
+.load-history-chart .chart-container {
+  text.title {
+    text-transform: capitalize;
+    color: var(--widget-text-color);
+  }
+  .axis, .chart-label {
+    fill: var(--widget-text-color);
+    opacity: var(--dimming-factor);
+    &:hover { opacity: 1; }
+  }
+}
+
+</style>

src/components/Widgets/WidgetBase.vue

@@ -109,6 +109,13 @@
         @error="handleError"
         :ref="widgetRef"
       />
+      <NdLoadHistory
+        v-else-if="widgetType === 'nd-load-history'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
       <IframeWidget
         v-else-if="widgetType === 'iframe'"
         :options="widgetOptions"
@@ -151,6 +158,7 @@ import StockPriceChart from '@/components/Widgets/StockPriceChart.vue';
 import Jokes from '@/components/Widgets/Jokes.vue';
 import Flights from '@/components/Widgets/Flights.vue';
 import NdCpuHistory from '@/components/Widgets/NdCpuHistory.vue';
+import NdLoadHistory from '@/components/Widgets/NdLoadHistory.vue';
 import IframeWidget from '@/components/Widgets/IframeWidget.vue';
 import EmbedWidget from '@/components/Widgets/EmbedWidget.vue';
 
@@ -174,6 +182,7 @@ export default {
     Jokes,
     Flights,
     NdCpuHistory,
+    NdLoadHistory,
     IframeWidget,
     EmbedWidget,
   },