dashboard: CPU, memory, diskIO and traffic on the footer (#15950)

* dashboard: footer, deep state update

* dashboard: resolve asset path

* dashboard: prevent state update on every reconnection

* dashboard: fix linter issue

* dashboard, cmd: minor UI fix, include commit hash

* dashboard: gitCommit renamed to commit

* dashboard: move the geth version to the right, make commit optional

* dashboard: memory, traffic and CPU on footer

* dashboard: fix merge

* dashboard: CPU, diskIO on footer

* dashboard: rename variables, use group declaration

* dashboard: docs

dashboard/assets/components/CustomTooltip.jsx

@@ -0,0 +1,95 @@
+// @flow
+
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+import React, {Component} from 'react';
+
+import Typography from 'material-ui/Typography';
+import {styles} from '../common';
+
+// multiplier multiplies a number by another.
+export const multiplier = <T>(by: number = 1) => (x: number) => x * by;
+
+// percentPlotter renders a tooltip, which displays the value of the payload followed by a percent sign.
+export const percentPlotter = <T>(text: string, mapper: (T => T) = multiplier(1)) => (payload: T) => {
+	const p = mapper(payload);
+	if (typeof p !== 'number') {
+		return null;
+	}
+	return (
+		<Typography type='caption' color='inherit'>
+			<span style={styles.light}>{text}</span> {p.toFixed(2)} %
+		</Typography>
+	);
+};
+
+// unit contains the units for the bytePlotter.
+const unit = ['B', 'KB', 'MB', 'GB', 'TB', 'PB'];
+
+// simplifyBytes returns the simplified version of the given value followed by the unit.
+const simplifyBytes = (x: number) => {
+	let i = 0;
+	for (; x > 1024 && i < 5; i++) {
+		x /= 1024;
+	}
+	return x.toFixed(2).toString().concat(' ', unit[i]);
+};
+
+// bytePlotter renders a tooltip, which displays the payload as a byte value.
+export const bytePlotter = <T>(text: string, mapper: (T => T) = multiplier(1)) => (payload: T) => {
+	const p = mapper(payload);
+	if (typeof p !== 'number') {
+		return null;
+	}
+	return (
+		<Typography type='caption' color='inherit'>
+			<span style={styles.light}>{text}</span> {simplifyBytes(p)}
+		</Typography>
+	);
+};
+
+// bytePlotter renders a tooltip, which displays the payload as a byte value followed by '/s'.
+export const bytePerSecPlotter = <T>(text: string, mapper: (T => T) = multiplier(1)) => (payload: T) => {
+	const p = mapper(payload);
+	if (typeof p !== 'number') {
+		return null;
+	}
+	return (
+		<Typography type='caption' color='inherit'>
+			<span style={styles.light}>{text}</span> {simplifyBytes(p)}/s
+		</Typography>
+	);
+};
+
+export type Props = {
+	active: boolean,
+	payload: Object,
+	tooltip: <T>(text: string, mapper?: T => T) => (payload: mixed) => null | React$Element<any>,
+};
+
+// CustomTooltip takes a tooltip function, and uses it to plot the active value of the chart.
+class CustomTooltip extends Component<Props> {
+	render() {
+		const {active, payload, tooltip} = this.props;
+		if (!active || typeof tooltip !== 'function') {
+			return null;
+		}
+		return tooltip(payload[0].value);
+	}
+}
+
+export default CustomTooltip;