cmd, dashboard, log: log collection and exploration (#17097)

* cmd, dashboard, internal, log, node: logging feature * cmd, dashboard, internal, log: requested changes * dashboard, vendor: gofmt, govendor, use vendored file watcher * dashboard, log: gofmt -s -w, goimports * dashboard, log: gosimple
2018-07-11 10:59:04 +03:00
parent 2eedbe799f
commit a9835c1816
28 changed files with 11444 additions and 8211 deletions
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -199,7 +199,12 @@ func init() {

 	app.Before = func(ctx *cli.Context) error {
 		runtime.GOMAXPROCS(runtime.NumCPU())
-		if err := debug.Setup(ctx); err != nil {
+
+		logdir := ""
+		if ctx.GlobalBool(utils.DashboardEnabledFlag.Name) {
+			logdir = (&node.Config{DataDir: utils.MakeDataDir(ctx)}).ResolvePath("logs")
+		}
+		if err := debug.Setup(ctx, logdir); err != nil {
 			return err
 		}
 		// Cap the cache allowance and tune the garbage collector
--- a/cmd/swarm/main.go
+++ b/cmd/swarm/main.go
@@ -432,7 +432,7 @@ pv(1) tool to get a progress bar:
 	app.Flags = append(app.Flags, swarmmetrics.Flags...)
 	app.Before = func(ctx *cli.Context) error {
 		runtime.GOMAXPROCS(runtime.NumCPU())
-		if err := debug.Setup(ctx); err != nil {
+		if err := debug.Setup(ctx, ""); err != nil {
 			return err
 		}
 		swarmmetrics.Setup(ctx)
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -193,7 +193,7 @@ var (
 	}
 	// Dashboard settings
 	DashboardEnabledFlag = cli.BoolFlag{
-		Name:  "dashboard",
+		Name:  metrics.DashboardEnabledFlag,
 		Usage: "Enable the dashboard",
 	}
 	DashboardAddrFlag = cli.StringFlag{
@@ -1185,7 +1185,7 @@ func RegisterEthService(stack *node.Node, cfg *eth.Config) {
 // RegisterDashboardService adds a dashboard to the stack.
 func RegisterDashboardService(stack *node.Node, cfg *dashboard.Config, commit string) {
 	stack.Register(func(ctx *node.ServiceContext) (node.Service, error) {
-		return dashboard.New(cfg, commit)
+		return dashboard.New(cfg, commit, ctx.ResolvePath("logs")), nil
 	})
 }

--- a/dashboard/assets.go
+++ b/dashboard/assets.go
--- a/dashboard/assets/common.jsx
+++ b/dashboard/assets/common.jsx
@@ -68,4 +68,4 @@ export const styles = {
 	light: {
 		color: 'rgba(255, 255, 255, 0.54)',
 	},
-}
+};
--- a/dashboard/assets/components/Body.jsx
+++ b/dashboard/assets/components/Body.jsx
@@ -32,11 +32,12 @@ const styles = {
 };

 export type Props = {
-	opened: boolean,
+	opened:        boolean,
 	changeContent: string => void,
-	active: string,
-	content: Content,
-	shouldUpdate: Object,
+	active:        string,
+	content:       Content,
+	shouldUpdate:  Object,
+	send:          string => void,
 };

 // Body renders the body of the dashboard.
@@ -52,6 +53,7 @@ class Body extends Component<Props> {
 					active={this.props.active}
 					content={this.props.content}
 					shouldUpdate={this.props.shouldUpdate}
+					send={this.props.send}
 				/>
 			</div>
 		);
--- a/dashboard/assets/components/CustomTooltip.jsx
+++ b/dashboard/assets/components/CustomTooltip.jsx
@@ -85,7 +85,7 @@ export type Props = {
 class CustomTooltip extends Component<Props> {
 	render() {
 		const {active, payload, tooltip} = this.props;
-		if (!active || typeof tooltip !== 'function') {
+		if (!active || typeof tooltip !== 'function' || !Array.isArray(payload) || payload.length < 1) {
 			return null;
 		}
 		return tooltip(payload[0].value);
--- a/dashboard/assets/components/Dashboard.jsx
+++ b/dashboard/assets/components/Dashboard.jsx
@@ -24,6 +24,7 @@ import Header from './Header';
 import Body from './Body';
 import {MENU} from '../common';
 import type {Content} from '../types/content';
+import {inserter as logInserter} from './Logs';

 // deepUpdate updates an object corresponding to the given update data, which has
 // the shape of the same structure as the original object. updater also has the same
@@ -75,8 +76,11 @@ const appender = <T>(limit: number, mapper = replacer) => (update: Array<T>, pre
 	...update.map(sample => mapper(sample)),
 ].slice(-limit);

-// defaultContent is the initial value of the state content.
-const defaultContent: Content = {
+// defaultContent returns the initial value of the state content. Needs to be a function in order to
+// instantiate the object again, because it is used by the state, and isn't automatically cleaned
+// when a new connection is established. The state is mutated during the update in order to avoid
+// the execution of unnecessary operations (e.g. copy of the log array).
+const defaultContent: () => Content = () => ({
 	general: {
 		version: null,
 		commit:  null,
@@ -95,10 +99,14 @@ const defaultContent: Content = {
 		diskRead:       [],
 		diskWrite:      [],
 	},
-	logs:    {
-		log: [],
+	logs: {
+		chunks:        [],
+		endTop:        false,
+		endBottom:     true,
+		topChanged:    0,
+		bottomChanged: 0,
 	},
-};
+});

 // updaters contains the state updater functions for each path of the state.
 //
@@ -122,9 +130,7 @@ const updaters = {
 		diskRead:       appender(200),
 		diskWrite:      appender(200),
 	},
-	logs: {
-		log: appender(200),
-	},
+	logs: logInserter(5),
 };

 // styles contains the constant styles of the component.
@@ -151,10 +157,11 @@ export type Props = {
 };

 type State = {
-	active: string, // active menu
-	sideBar: boolean, // true if the sidebar is opened
-	content: Content, // the visualized data
-	shouldUpdate: Object, // labels for the components, which need to re-render based on the incoming message
+	active:       string,  // active menu
+	sideBar:      boolean, // true if the sidebar is opened
+	content:      Content, // the visualized data
+	shouldUpdate: Object,  // labels for the components, which need to re-render based on the incoming message
+	server:       ?WebSocket,
 };

 // Dashboard is the main component, which renders the whole page, makes connection with the server and
@@ -165,8 +172,9 @@ class Dashboard extends Component<Props, State> {
 		this.state = {
 			active:       MENU.get('home').id,
 			sideBar:      true,
-			content:      defaultContent,
+			content:      defaultContent(),
 			shouldUpdate: {},
+			server:       null,
 		};
 	}

@@ -181,7 +189,7 @@ class Dashboard extends Component<Props, State> {
 		// PROD is defined by webpack.
 		const server = new WebSocket(`${((window.location.protocol === 'https:') ? 'wss://' : 'ws://')}${PROD ? window.location.host : 'localhost:8080'}/api`);
 		server.onopen = () => {
-			this.setState({content: defaultContent, shouldUpdate: {}});
+			this.setState({content: defaultContent(), shouldUpdate: {}, server});
 		};
 		server.onmessage = (event) => {
 			const msg: $Shape<Content> = JSON.parse(event.data);
@@ -192,10 +200,18 @@ class Dashboard extends Component<Props, State> {
 			this.update(msg);
 		};
 		server.onclose = () => {
+			this.setState({server: null});
 			setTimeout(this.reconnect, 3000);
 		};
 	};

+	// send sends a message to the server, which can be accessed only through this function for safety reasons.
+	send = (msg: string) => {
+		if (this.state.server != null) {
+			this.state.server.send(msg);
+		}
+	};
+
 	// update updates the content corresponding to the incoming message.
 	update = (msg: $Shape<Content>) => {
 		this.setState(prevState => ({
@@ -226,6 +242,7 @@ class Dashboard extends Component<Props, State> {
 					active={this.state.active}
 					content={this.state.content}
 					shouldUpdate={this.state.shouldUpdate}
+					send={this.send}
 				/>
 			</div>
 		);
--- a/dashboard/assets/components/Logs.jsx
+++ b/dashboard/assets/components/Logs.jsx
@@ -0,0 +1,310 @@
+// @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 List, {ListItem} from 'material-ui/List';
+import type {Record, Content, LogsMessage, Logs as LogsType} from '../types/content';
+
+// requestBand says how wide is the top/bottom zone, eg. 0.1 means 10% of the container height.
+const requestBand = 0.05;
+
+// fieldPadding is a global map with maximum field value lengths seen until now
+// to allow padding log contexts in a bit smarter way.
+const fieldPadding = new Map();
+
+// createChunk creates an HTML formatted object, which displays the given array similarly to
+// the server side terminal.
+const createChunk = (records: Array<Record>) => {
+	let content = '';
+	records.forEach((record) => {
+		const {t, ctx} = record;
+		let {lvl, msg} = record;
+		let color = '#ce3c23';
+		switch (lvl) {
+		case 'trace':
+		case 'trce':
+			lvl = 'TRACE';
+			color = '#3465a4';
+			break;
+		case 'debug':
+		case 'dbug':
+			lvl = 'DEBUG';
+			color = '#3d989b';
+			break;
+		case 'info':
+			lvl = 'INFO&nbsp;';
+			color = '#4c8f0f';
+			break;
+		case 'warn':
+			lvl = 'WARN&nbsp;';
+			color = '#b79a22';
+			break;
+		case 'error':
+		case 'eror':
+			lvl = 'ERROR';
+			color = '#754b70';
+			break;
+		case 'crit':
+			lvl = 'CRIT&nbsp;';
+			color = '#ce3c23';
+			break;
+		default:
+			lvl = '';
+		}
+		const time = new Date(t);
+		if (lvl === '' || !(time instanceof Date) || isNaN(time) || typeof msg !== 'string' || !Array.isArray(ctx)) {
+			content += '<span style="color:#ce3c23">Invalid log record</span><br />';
+			return;
+		}
+		if (ctx.length > 0) {
+			msg += '&nbsp;'.repeat(Math.max(40 - msg.length, 0));
+		}
+		const month = `0${time.getMonth() + 1}`.slice(-2);
+		const date = `0${time.getDate()}`.slice(-2);
+		const hours = `0${time.getHours()}`.slice(-2);
+		const minutes = `0${time.getMinutes()}`.slice(-2);
+		const seconds = `0${time.getSeconds()}`.slice(-2);
+		content += `<span style="color:${color}">${lvl}</span>[${month}-${date}|${hours}:${minutes}:${seconds}] ${msg}`;
+
+		for (let i = 0; i < ctx.length; i += 2) {
+			const key = ctx[i];
+			const val = ctx[i + 1];
+			let padding = fieldPadding.get(key);
+			if (typeof padding !== 'number' || padding < val.length) {
+				padding = val.length;
+				fieldPadding.set(key, padding);
+			}
+			let p = '';
+			if (i < ctx.length - 2) {
+				p = '&nbsp;'.repeat(padding - val.length);
+			}
+			content += ` <span style="color:${color}">${key}</span>=${val}${p}`;
+		}
+		content += '<br />';
+	});
+	return content;
+};
+
+// inserter is a state updater function for the main component, which inserts the new log chunk into the chunk array.
+// limit is the maximum length of the chunk array, used in order to prevent the browser from OOM.
+export const inserter = (limit: number) => (update: LogsMessage, prev: LogsType) => {
+	prev.topChanged = 0;
+	prev.bottomChanged = 0;
+	if (!Array.isArray(update.chunk) || update.chunk.length < 1) {
+		return prev;
+	}
+	if (!Array.isArray(prev.chunks)) {
+		prev.chunks = [];
+	}
+	const content = createChunk(update.chunk);
+	if (!update.source) {
+		// In case of stream chunk.
+		if (!prev.endBottom) {
+			return prev;
+		}
+		if (prev.chunks.length < 1) {
+			// This should never happen, because the first chunk is always a non-stream chunk.
+			return [{content, name: '00000000000000.log'}];
+		}
+		prev.chunks[prev.chunks.length - 1].content += content;
+		prev.bottomChanged = 1;
+		return prev;
+	}
+	const chunk = {
+		content,
+		name: update.source.name,
+	};
+	if (prev.chunks.length > 0 && update.source.name < prev.chunks[0].name) {
+		if (update.source.last) {
+			prev.endTop = true;
+		}
+		if (prev.chunks.length >= limit) {
+			prev.endBottom = false;
+			prev.chunks.splice(limit - 1, prev.chunks.length - limit + 1);
+			prev.bottomChanged = -1;
+		}
+		prev.chunks = [chunk, ...prev.chunks];
+		prev.topChanged = 1;
+		return prev;
+	}
+	if (update.source.last) {
+		prev.endBottom = true;
+	}
+	if (prev.chunks.length >= limit) {
+		prev.endTop = false;
+		prev.chunks.splice(0, prev.chunks.length - limit + 1);
+		prev.topChanged = -1;
+	}
+	prev.chunks = [...prev.chunks, chunk];
+	prev.bottomChanged = 1;
+	return prev;
+};
+
+// styles contains the constant styles of the component.
+const styles = {
+	logListItem: {
+		padding: 0,
+	},
+	logChunk: {
+		color:      'white',
+		fontFamily: 'monospace',
+		whiteSpace: 'nowrap',
+		width:      0,
+	},
+};
+
+export type Props = {
+	container:    Object,
+	content:      Content,
+	shouldUpdate: Object,
+	send:         string => void,
+};
+
+type State = {
+	requestAllowed: boolean,
+};
+
+// Logs renders the log page.
+class Logs extends Component<Props, State> {
+	constructor(props: Props) {
+		super(props);
+		this.content = React.createRef();
+		this.state = {
+			requestAllowed: true,
+		};
+	}
+
+	componentDidMount() {
+		const {container} = this.props;
+		container.scrollTop = container.scrollHeight - container.clientHeight;
+	}
+
+	// onScroll is triggered by the parent component's scroll event, and sends requests if the scroll position is
+	// at the top or at the bottom.
+	onScroll = () => {
+		if (!this.state.requestAllowed || typeof this.content === 'undefined') {
+			return;
+		}
+		const {logs} = this.props.content;
+		if (logs.chunks.length < 1) {
+			return;
+		}
+		if (this.atTop()) {
+			if (!logs.endTop) {
+				this.setState({requestAllowed: false});
+				this.props.send(JSON.stringify({
+					Logs: {
+						Name: logs.chunks[0].name,
+						Past: true,
+					},
+				}));
+			}
+		} else if (this.atBottom()) {
+			if (!logs.endBottom) {
+				this.setState({requestAllowed: false});
+				this.props.send(JSON.stringify({
+					Logs: {
+						Name: logs.chunks[logs.chunks.length - 1].name,
+						Past: false,
+					},
+				}));
+			}
+		}
+	};
+
+	// atTop checks if the scroll position it at the top of the container.
+	atTop = () => this.props.container.scrollTop <= this.props.container.scrollHeight * requestBand;
+
+	// atBottom checks if the scroll position it at the bottom of the container.
+	atBottom = () => {
+		const {container} = this.props;
+		return container.scrollHeight - container.scrollTop <=
+			container.clientHeight + container.scrollHeight * requestBand;
+	};
+
+	// beforeUpdate is called by the parent component, saves the previous scroll position
+	// and the height of the first log chunk, which can be deleted during the insertion.
+	beforeUpdate = () => {
+		let firstHeight = 0;
+		if (this.content && this.content.children[0] && this.content.children[0].children[0]) {
+			firstHeight = this.content.children[0].children[0].clientHeight;
+		}
+		return {
+			scrollTop: this.props.container.scrollTop,
+			firstHeight,
+		};
+	};
+
+	// didUpdate is called by the parent component, which provides the container. Sends the first request if the
+	// visible part of the container isn't full, and resets the scroll position in order to avoid jumping when new
+	// chunk is inserted.
+	didUpdate = (prevProps, prevState, snapshot) => {
+		if (typeof this.props.shouldUpdate.logs === 'undefined' || typeof this.content === 'undefined' || snapshot === null) {
+			return;
+		}
+		const {logs} = this.props.content;
+		const {container} = this.props;
+		if (typeof container === 'undefined' || logs.chunks.length < 1) {
+			return;
+		}
+		if (this.content.clientHeight < container.clientHeight) {
+			// Only enters here at the beginning, when there isn't enough log to fill the container
+			// and the scroll bar doesn't appear.
+			if (!logs.endTop) {
+				this.setState({requestAllowed: false});
+				this.props.send(JSON.stringify({
+					Logs: {
+						Name: logs.chunks[0].name,
+						Past: true,
+					},
+				}));
+			}
+			return;
+		}
+		const chunks = this.content.children[0].children;
+		let {scrollTop} = snapshot;
+		if (logs.topChanged > 0) {
+			scrollTop += chunks[0].clientHeight;
+		} else if (logs.bottomChanged > 0) {
+			if (logs.topChanged < 0) {
+				scrollTop -= snapshot.firstHeight;
+			} else if (logs.endBottom && this.atBottom()) {
+				scrollTop = container.scrollHeight - container.clientHeight;
+			}
+		}
+		container.scrollTop = scrollTop;
+		this.setState({requestAllowed: true});
+	};
+
+	render() {
+		return (
+			<div ref={(ref) => { this.content = ref; }}>
+				<List>
+					{this.props.content.logs.chunks.map((c, index) => (
+						<ListItem style={styles.logListItem} key={index}>
+							<div style={styles.logChunk} dangerouslySetInnerHTML={{__html: c.content}} />
+						</ListItem>
+					))}
+				</List>
+			</div>
+		);
+	}
+}
+
+export default Logs;
--- a/dashboard/assets/components/Main.jsx
+++ b/dashboard/assets/components/Main.jsx
@@ -21,6 +21,7 @@ import React, {Component} from 'react';
 import withStyles from 'material-ui/styles/withStyles';

 import {MENU} from '../common';
+import Logs from './Logs';
 import Footer from './Footer';
 import type {Content} from '../types/content';

@@ -32,7 +33,7 @@ const styles = {
 		width:         '100%',
 	},
 	content: {
-		flex:     1,
+		flex:      1,
 		overflow: 'auto',
 	},
 };
@@ -46,14 +47,40 @@ const themeStyles = theme => ({
 });

 export type Props = {
-	classes: Object,
-	active: string,
-	content: Content,
+	classes:      Object,
+	active:       string,
+	content:      Content,
 	shouldUpdate: Object,
+	send:         string => void,
 };

 // Main renders the chosen content.
 class Main extends Component<Props> {
+	constructor(props) {
+		super(props);
+		this.container = React.createRef();
+		this.content = React.createRef();
+	}
+
+	getSnapshotBeforeUpdate() {
+		if (this.content && typeof this.content.beforeUpdate === 'function') {
+			return this.content.beforeUpdate();
+		}
+		return null;
+	}
+
+	componentDidUpdate(prevProps, prevState, snapshot) {
+		if (this.content && typeof this.content.didUpdate === 'function') {
+			this.content.didUpdate(prevProps, prevState, snapshot);
+		}
+	}
+
+	onScroll = () => {
+		if (this.content && typeof this.content.onScroll === 'function') {
+			this.content.onScroll();
+		}
+	};
+
 	render() {
 		const {
 			classes, active, content, shouldUpdate,
@@ -69,12 +96,27 @@ class Main extends Component<Props> {
 			children = <div>Work in progress.</div>;
 			break;
 		case MENU.get('logs').id:
-			children = <div>{content.logs.log.map((log, index) => <div key={index}>{log}</div>)}</div>;
+			children = (
+				<Logs
+					ref={(ref) => { this.content = ref; }}
+					container={this.container}
+					send={this.props.send}
+					content={this.props.content}
+					shouldUpdate={shouldUpdate}
+				/>
+			);
 		}

 		return (
 			<div style={styles.wrapper}>
-				<div className={classes.content} style={styles.content}>{children}</div>
+				<div
+					className={classes.content}
+					style={styles.content}
+					ref={(ref) => { this.container = ref; }}
+					onScroll={this.onScroll}
+				>
+					{children}
+				</div>
 				<Footer
 					general={content.general}
 					system={content.system}
--- a/dashboard/assets/index.html
+++ b/dashboard/assets/index.html
@@ -14,6 +14,9 @@
            ::-webkit-scrollbar-thumb {
                background: #212121;
            }
+            ::-webkit-scrollbar-corner {
+                background: transparent;
+            }
        </style>
    </head>
    <body style="height: 100%; margin: 0">
--- a/dashboard/assets/types/content.jsx
+++ b/dashboard/assets/types/content.jsx
@@ -18,24 +18,24 @@

 export type Content = {
 	general: General,
-	home: Home,
-	chain: Chain,
-	txpool: TxPool,
+	home:    Home,
+	chain:   Chain,
+	txpool:  TxPool,
 	network: Network,
-	system: System,
-	logs: Logs,
+	system:  System,
+	logs:    Logs,
 };

 export type ChartEntries = Array<ChartEntry>;

 export type ChartEntry = {
-	time: Date,
+	time:  Date,
 	value: number,
 };

 export type General = {
-    version: ?string,
-    commit: ?string,
+	version: ?string,
+	commit:  ?string,
 };

 export type Home = {
@@ -55,16 +55,42 @@ export type Network = {
 };

 export type System = {
-    activeMemory: ChartEntries,
-    virtualMemory: ChartEntries,
-    networkIngress: ChartEntries,
-    networkEgress: ChartEntries,
-    processCPU: ChartEntries,
-    systemCPU: ChartEntries,
-    diskRead: ChartEntries,
-    diskWrite: ChartEntries,
+	activeMemory:   ChartEntries,
+	virtualMemory:  ChartEntries,
+	networkIngress: ChartEntries,
+	networkEgress:  ChartEntries,
+	processCPU:     ChartEntries,
+	systemCPU:      ChartEntries,
+	diskRead:       ChartEntries,
+	diskWrite:      ChartEntries,
+};
+
+export type Record = {
+	t:   string,
+	lvl: Object,
+	msg: string,
+	ctx: Array<string>
+};
+
+export type Chunk = {
+	content: string,
+	name:    string,
 };

 export type Logs = {
-	log: Array<string>,
+	chunks:        Array<Chunk>,
+	endTop:        boolean,
+	endBottom:     boolean,
+	topChanged:    number,
+	bottomChanged: number,
+};
+
+export type LogsMessage = {
+	source: ?LogFile,
+	chunk:  Array<Record>,
+};
+
+export type LogFile = {
+	name: string,
+	last: string,
 };
--- a/dashboard/assets/yarn.lock
+++ b/dashboard/assets/yarn.lock
@@ -2,70 +2,77 @@
 # yarn lockfile v1


-"@babel/code-frame@7.0.0-beta.40", "@babel/code-frame@^7.0.0-beta.40":
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/@babel/code-frame/-/code-frame-7.0.0-beta.40.tgz#37e2b0cf7c56026b4b21d3927cadf81adec32ac6"
+"@babel/code-frame@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/code-frame/-/code-frame-7.0.0-beta.44.tgz#2a02643368de80916162be70865c97774f3adbd9"
  dependencies:
-    "@babel/highlight" "7.0.0-beta.40"
+    "@babel/highlight" "7.0.0-beta.44"

-"@babel/generator@7.0.0-beta.40":
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/@babel/generator/-/generator-7.0.0-beta.40.tgz#ab61f9556f4f71dbd1138949c795bb9a21e302ea"
+"@babel/generator@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/generator/-/generator-7.0.0-beta.44.tgz#c7e67b9b5284afcf69b309b50d7d37f3e5033d42"
  dependencies:
-    "@babel/types" "7.0.0-beta.40"
+    "@babel/types" "7.0.0-beta.44"
    jsesc "^2.5.1"
    lodash "^4.2.0"
    source-map "^0.5.0"
    trim-right "^1.0.1"

-"@babel/helper-function-name@7.0.0-beta.40":
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/@babel/helper-function-name/-/helper-function-name-7.0.0-beta.40.tgz#9d033341ab16517f40d43a73f2d81fc431ccd7b6"
+"@babel/helper-function-name@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/helper-function-name/-/helper-function-name-7.0.0-beta.44.tgz#e18552aaae2231100a6e485e03854bc3532d44dd"
  dependencies:
-    "@babel/helper-get-function-arity" "7.0.0-beta.40"
-    "@babel/template" "7.0.0-beta.40"
-    "@babel/types" "7.0.0-beta.40"
+    "@babel/helper-get-function-arity" "7.0.0-beta.44"
+    "@babel/template" "7.0.0-beta.44"
+    "@babel/types" "7.0.0-beta.44"

-"@babel/helper-get-function-arity@7.0.0-beta.40":
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/@babel/helper-get-function-arity/-/helper-get-function-arity-7.0.0-beta.40.tgz#ac0419cf067b0ec16453e1274f03878195791c6e"
+"@babel/helper-get-function-arity@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/helper-get-function-arity/-/helper-get-function-arity-7.0.0-beta.44.tgz#d03ca6dd2b9f7b0b1e6b32c56c72836140db3a15"
  dependencies:
-    "@babel/types" "7.0.0-beta.40"
+    "@babel/types" "7.0.0-beta.44"

-"@babel/highlight@7.0.0-beta.40":
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/@babel/highlight/-/highlight-7.0.0-beta.40.tgz#b43d67d76bf46e1d10d227f68cddcd263786b255"
+"@babel/helper-split-export-declaration@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/helper-split-export-declaration/-/helper-split-export-declaration-7.0.0-beta.44.tgz#c0b351735e0fbcb3822c8ad8db4e583b05ebd9dc"
+  dependencies:
+    "@babel/types" "7.0.0-beta.44"
+
+"@babel/highlight@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/highlight/-/highlight-7.0.0-beta.44.tgz#18c94ce543916a80553edcdcf681890b200747d5"
  dependencies:
    chalk "^2.0.0"
    esutils "^2.0.2"
    js-tokens "^3.0.0"

-"@babel/template@7.0.0-beta.40":
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/@babel/template/-/template-7.0.0-beta.40.tgz#034988c6424eb5c3268fe6a608626de1f4410fc8"
+"@babel/template@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/template/-/template-7.0.0-beta.44.tgz#f8832f4fdcee5d59bf515e595fc5106c529b394f"
  dependencies:
-    "@babel/code-frame" "7.0.0-beta.40"
-    "@babel/types" "7.0.0-beta.40"
-    babylon "7.0.0-beta.40"
+    "@babel/code-frame" "7.0.0-beta.44"
+    "@babel/types" "7.0.0-beta.44"
+    babylon "7.0.0-beta.44"
    lodash "^4.2.0"

-"@babel/traverse@^7.0.0-beta.40":
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/@babel/traverse/-/traverse-7.0.0-beta.40.tgz#d140e449b2e093ef9fe1a2eecc28421ffb4e521e"
+"@babel/traverse@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/traverse/-/traverse-7.0.0-beta.44.tgz#a970a2c45477ad18017e2e465a0606feee0d2966"
  dependencies:
-    "@babel/code-frame" "7.0.0-beta.40"
-    "@babel/generator" "7.0.0-beta.40"
-    "@babel/helper-function-name" "7.0.0-beta.40"
-    "@babel/types" "7.0.0-beta.40"
-    babylon "7.0.0-beta.40"
-    debug "^3.0.1"
+    "@babel/code-frame" "7.0.0-beta.44"
+    "@babel/generator" "7.0.0-beta.44"
+    "@babel/helper-function-name" "7.0.0-beta.44"
+    "@babel/helper-split-export-declaration" "7.0.0-beta.44"
+    "@babel/types" "7.0.0-beta.44"
+    babylon "7.0.0-beta.44"
+    debug "^3.1.0"
    globals "^11.1.0"
    invariant "^2.2.0"
    lodash "^4.2.0"

-"@babel/types@7.0.0-beta.40", "@babel/types@^7.0.0-beta.40":
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/@babel/types/-/types-7.0.0-beta.40.tgz#25c3d7aae14126abe05fcb098c65a66b6d6b8c14"
+"@babel/types@7.0.0-beta.44":
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/@babel/types/-/types-7.0.0-beta.44.tgz#6b1b164591f77dec0a0342aca995f2d046b3a757"
  dependencies:
    esutils "^2.0.2"
    lodash "^4.2.0"
@@ -376,8 +383,8 @@ babel-code-frame@^6.22.0, babel-code-frame@^6.26.0:
    js-tokens "^3.0.2"

 babel-core@^6.26.0:
-  version "6.26.0"
-  resolved "https://registry.yarnpkg.com/babel-core/-/babel-core-6.26.0.tgz#af32f78b31a6fcef119c87b0fd8d9753f03a0bb8"
+  version "6.26.3"
+  resolved "https://registry.yarnpkg.com/babel-core/-/babel-core-6.26.3.tgz#b2e2f09e342d0f0c88e2f02e067794125e75c207"
  dependencies:
    babel-code-frame "^6.26.0"
    babel-generator "^6.26.0"
@@ -389,24 +396,24 @@ babel-core@^6.26.0:
    babel-traverse "^6.26.0"
    babel-types "^6.26.0"
    babylon "^6.18.0"
-    convert-source-map "^1.5.0"
-    debug "^2.6.8"
+    convert-source-map "^1.5.1"
+    debug "^2.6.9"
    json5 "^0.5.1"
    lodash "^4.17.4"
    minimatch "^3.0.4"
    path-is-absolute "^1.0.1"
-    private "^0.1.7"
+    private "^0.1.8"
    slash "^1.0.0"
-    source-map "^0.5.6"
+    source-map "^0.5.7"

 babel-eslint@^8.2.1:
-  version "8.2.2"
-  resolved "https://registry.yarnpkg.com/babel-eslint/-/babel-eslint-8.2.2.tgz#1102273354c6f0b29b4ea28a65f97d122296b68b"
+  version "8.2.3"
+  resolved "https://registry.yarnpkg.com/babel-eslint/-/babel-eslint-8.2.3.tgz#1a2e6681cc9bc4473c32899e59915e19cd6733cf"
  dependencies:
-    "@babel/code-frame" "^7.0.0-beta.40"
-    "@babel/traverse" "^7.0.0-beta.40"
-    "@babel/types" "^7.0.0-beta.40"
-    babylon "^7.0.0-beta.40"
+    "@babel/code-frame" "7.0.0-beta.44"
+    "@babel/traverse" "7.0.0-beta.44"
+    "@babel/types" "7.0.0-beta.44"
+    babylon "7.0.0-beta.44"
    eslint-scope "~3.7.1"
    eslint-visitor-keys "^1.0.0"

@@ -550,8 +557,8 @@ babel-helpers@^6.24.1:
    babel-template "^6.24.1"

 babel-loader@^7.1.2:
-  version "7.1.3"
-  resolved "https://registry.yarnpkg.com/babel-loader/-/babel-loader-7.1.3.tgz#ff5b440da716e9153abb946251a9ab7670037b16"
+  version "7.1.4"
+  resolved "https://registry.yarnpkg.com/babel-loader/-/babel-loader-7.1.4.tgz#e3463938bd4e6d55d1c174c5485d406a188ed015"
  dependencies:
    find-cache-dir "^1.0.0"
    loader-utils "^1.0.2"
@@ -1081,9 +1088,9 @@ babel-types@^6.19.0, babel-types@^6.24.1, babel-types@^6.26.0:
    lodash "^4.17.4"
    to-fast-properties "^1.0.3"

-babylon@7.0.0-beta.40, babylon@^7.0.0-beta.40:
-  version "7.0.0-beta.40"
-  resolved "https://registry.yarnpkg.com/babylon/-/babylon-7.0.0-beta.40.tgz#91fc8cd56d5eb98b28e6fde41045f2957779940a"
+babylon@7.0.0-beta.44:
+  version "7.0.0-beta.44"
+  resolved "https://registry.yarnpkg.com/babylon/-/babylon-7.0.0-beta.44.tgz#89159e15e6e30c5096e22d738d8c0af8a0e8ca1d"

 babylon@^6.18.0:
  version "6.18.0"
@@ -1413,7 +1420,15 @@ chalk@^1.1.3:
    strip-ansi "^3.0.0"
    supports-color "^2.0.0"

-chalk@^2.0.0, chalk@^2.1.0, chalk@^2.3.1:
+chalk@^2.0.0:
+  version "2.4.1"
+  resolved "https://registry.yarnpkg.com/chalk/-/chalk-2.4.1.tgz#18c49ab16a037b6eb0152cc83e3471338215b66e"
+  dependencies:
+    ansi-styles "^3.2.1"
+    escape-string-regexp "^1.0.5"
+    supports-color "^5.3.0"
+
+chalk@^2.1.0, chalk@^2.3.1:
  version "2.3.2"
  resolved "https://registry.yarnpkg.com/chalk/-/chalk-2.3.2.tgz#250dc96b07491bfd601e648d66ddf5f60c7a5c65"
  dependencies:
@@ -1646,7 +1661,7 @@ content-type@~1.0.4:
  version "1.0.4"
  resolved "https://registry.yarnpkg.com/content-type/-/content-type-1.0.4.tgz#e138cc75e040c727b1966fe5e5f8c9aee256fe3b"

-convert-source-map@^1.5.0:
+convert-source-map@^1.5.1:
  version "1.5.1"
  resolved "https://registry.yarnpkg.com/convert-source-map/-/convert-source-map-1.5.1.tgz#b8278097b9bc229365de5c62cf5fcaed8b5599e5"

@@ -1671,8 +1686,8 @@ core-js@^1.0.0:
  resolved "https://registry.yarnpkg.com/core-js/-/core-js-1.2.7.tgz#652294c14651db28fa93bd2d5ff2983a4f08c636"

 core-js@^2.4.0, core-js@^2.5.0:
-  version "2.5.3"
-  resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.5.3.tgz#8acc38345824f16d8365b7c9b4259168e8ed603e"
+  version "2.5.7"
+  resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.5.7.tgz#f972608ff0cead68b841a16a932d0b183791814e"

 core-util-is@1.0.2, core-util-is@~1.0.0:
  version "1.0.2"
@@ -1914,7 +1929,7 @@ debug@2.6.9, debug@^2.2.0, debug@^2.3.3, debug@^2.6.6, debug@^2.6.8, debug@^2.6.
  dependencies:
    ms "2.0.0"

-debug@^3.0.1, debug@^3.1.0:
+debug@^3.1.0:
  version "3.1.0"
  resolved "https://registry.yarnpkg.com/debug/-/debug-3.1.0.tgz#5bb5a0672628b64149566ba16819e61518c67261"
  dependencies:
@@ -2916,10 +2931,14 @@ global@~4.3.0:
    min-document "^2.19.0"
    process "~0.5.1"

-globals@^11.0.1, globals@^11.1.0:
+globals@^11.0.1:
  version "11.3.0"
  resolved "https://registry.yarnpkg.com/globals/-/globals-11.3.0.tgz#e04fdb7b9796d8adac9c8f64c14837b2313378b0"

+globals@^11.1.0:
+  version "11.5.0"
+  resolved "https://registry.yarnpkg.com/globals/-/globals-11.5.0.tgz#6bc840de6771173b191f13d3a9c94d441ee92642"
+
 globals@^9.18.0:
  version "9.18.0"
  resolved "https://registry.yarnpkg.com/globals/-/globals-9.18.0.tgz#aa3896b3e69b487f17e31ed2143d69a8e30c2d8a"
@@ -3176,10 +3195,16 @@ hyphenate-style-name@^1.0.2:
  version "1.0.2"
  resolved "https://registry.yarnpkg.com/hyphenate-style-name/-/hyphenate-style-name-1.0.2.tgz#31160a36930adaf1fc04c6074f7eb41465d4ec4b"

-iconv-lite@0.4.19, iconv-lite@^0.4.17, iconv-lite@~0.4.13:
+iconv-lite@0.4.19, iconv-lite@^0.4.17:
  version "0.4.19"
  resolved "https://registry.yarnpkg.com/iconv-lite/-/iconv-lite-0.4.19.tgz#f7468f60135f5e5dad3399c0a81be9a1603a082b"

+iconv-lite@~0.4.13:
+  version "0.4.23"
+  resolved "https://registry.yarnpkg.com/iconv-lite/-/iconv-lite-0.4.23.tgz#297871f63be507adcfbfca715d0cd0eed84e9a63"
+  dependencies:
+    safer-buffer ">= 2.1.2 < 3"
+
 icss-replace-symbols@^1.1.0:
  version "1.1.0"
  resolved "https://registry.yarnpkg.com/icss-replace-symbols/-/icss-replace-symbols-1.1.0.tgz#06ea6f83679a7749e386cfe1fe812ae5db223ded"
@@ -3272,8 +3297,8 @@ interpret@^1.0.0:
  resolved "https://registry.yarnpkg.com/interpret/-/interpret-1.1.0.tgz#7ed1b1410c6a0e0f78cf95d3b8440c63f78b8614"

 invariant@^2.2.0, invariant@^2.2.2:
-  version "2.2.3"
-  resolved "https://registry.yarnpkg.com/invariant/-/invariant-2.2.3.tgz#1a827dfde7dcbd7c323f0ca826be8fa7c5e9d688"
+  version "2.2.4"
+  resolved "https://registry.yarnpkg.com/invariant/-/invariant-2.2.4.tgz#610f3c92c9359ce1db616e538008d23ff35158e6"
  dependencies:
    loose-envify "^1.0.0"

@@ -3863,10 +3888,14 @@ lodash.uniq@^4.5.0:
  version "4.5.0"
  resolved "https://registry.yarnpkg.com/lodash.uniq/-/lodash.uniq-4.5.0.tgz#d0225373aeb652adc1bc82e4945339a842754773"

-lodash@^4.14.0, lodash@^4.15.0, lodash@^4.17.2, lodash@^4.17.4, lodash@^4.2.0, lodash@^4.3.0, lodash@~4.17.4:
+lodash@^4.14.0, lodash@^4.15.0, lodash@^4.17.2, lodash@^4.3.0, lodash@~4.17.4:
  version "4.17.5"
  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.5.tgz#99a92d65c0272debe8c96b6057bc8fbfa3bed511"

+lodash@^4.17.4, lodash@^4.2.0:
+  version "4.17.10"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.10.tgz#1b7793cf7259ea38fb3661d4d38b3260af8ae4e7"
+
 loglevel@^1.4.1:
  version "1.6.1"
  resolved "https://registry.yarnpkg.com/loglevel/-/loglevel-1.6.1.tgz#e0fc95133b6ef276cdc8887cdaf24aa6f156f8fa"
@@ -3904,8 +3933,8 @@ macaddress@^0.2.8:
  resolved "https://registry.yarnpkg.com/macaddress/-/macaddress-0.2.8.tgz#5904dc537c39ec6dbefeae902327135fa8511f12"

 make-dir@^1.0.0:
-  version "1.2.0"
-  resolved "https://registry.yarnpkg.com/make-dir/-/make-dir-1.2.0.tgz#6d6a49eead4aae296c53bbf3a1a008bd6c89469b"
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/make-dir/-/make-dir-1.3.0.tgz#79c1033b80515bd6d24ec9933e860ca75ee27f0c"
  dependencies:
    pify "^3.0.0"

@@ -4895,7 +4924,7 @@ preserve@^0.2.0:
  version "0.2.0"
  resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"

-private@^0.1.6, private@^0.1.7:
+private@^0.1.6, private@^0.1.8:
  version "0.1.8"
  resolved "https://registry.yarnpkg.com/private/-/private-0.1.8.tgz#2381edb3689f7a53d653190060fcf822d2f368ff"

@@ -5061,8 +5090,8 @@ rc@^1.1.7:
    strip-json-comments "~2.0.1"

 react-dom@^16.2.0:
-  version "16.2.0"
-  resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-16.2.0.tgz#69003178601c0ca19b709b33a83369fe6124c044"
+  version "16.4.0"
+  resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-16.4.0.tgz#099f067dd5827ce36a29eaf9a6cdc7cbf6216b1e"
  dependencies:
    fbjs "^0.8.16"
    loose-envify "^1.1.0"
@@ -5138,8 +5167,8 @@ react-transition-group@^2.2.1:
    warning "^3.0.0"

 react@^16.2.0:
-  version "16.2.0"
-  resolved "https://registry.yarnpkg.com/react/-/react-16.2.0.tgz#a31bd2dab89bff65d42134fa187f24d054c273ba"
+  version "16.4.0"
+  resolved "https://registry.yarnpkg.com/react/-/react-16.4.0.tgz#402c2db83335336fba1962c08b98c6272617d585"
  dependencies:
    fbjs "^0.8.16"
    loose-envify "^1.1.0"
@@ -5471,6 +5500,10 @@ safe-regex@^1.1.0:
  dependencies:
    ret "~0.1.10"

+"safer-buffer@>= 2.1.2 < 3":
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/safer-buffer/-/safer-buffer-2.1.2.tgz#44fa161b0187b9549dd84bb91802f9bd8385cd6a"
+
 sax@~1.2.1:
  version "1.2.4"
  resolved "https://registry.yarnpkg.com/sax/-/sax-1.2.4.tgz#2816234e2378bddc4e5354fab5caa895df7100d9"
@@ -5914,12 +5947,18 @@ supports-color@^4.2.1:
  dependencies:
    has-flag "^2.0.0"

-supports-color@^5.1.0, supports-color@^5.2.0, supports-color@^5.3.0:
+supports-color@^5.1.0, supports-color@^5.2.0:
  version "5.3.0"
  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-5.3.0.tgz#5b24ac15db80fa927cf5227a4a33fd3c4c7676c0"
  dependencies:
    has-flag "^3.0.0"

+supports-color@^5.3.0:
+  version "5.4.0"
+  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-5.4.0.tgz#1c6b337402c2137605efe19f10fec390f6faab54"
+  dependencies:
+    has-flag "^3.0.0"
+
 svgo@^0.7.0:
  version "0.7.2"
  resolved "https://registry.yarnpkg.com/svgo/-/svgo-0.7.2.tgz#9f5772413952135c6fefbf40afe6a4faa88b4bb5"
@@ -6108,8 +6147,8 @@ typedarray@^0.0.6:
  resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"

 ua-parser-js@^0.7.9:
-  version "0.7.17"
-  resolved "https://registry.yarnpkg.com/ua-parser-js/-/ua-parser-js-0.7.17.tgz#e9ec5f9498b9ec910e7ae3ac626a805c4d09ecac"
+  version "0.7.18"
+  resolved "https://registry.yarnpkg.com/ua-parser-js/-/ua-parser-js-0.7.18.tgz#a7bfd92f56edfb117083b69e31d2aa8882d4b1ed"

 uglify-js@^2.8.29:
  version "2.8.29"
@@ -6395,8 +6434,8 @@ websocket-extensions@>=0.1.1:
  resolved "https://registry.yarnpkg.com/websocket-extensions/-/websocket-extensions-0.1.3.tgz#5d2ff22977003ec687a4b87073dfbbac146ccf29"

 whatwg-fetch@>=0.10.0:
-  version "2.0.3"
-  resolved "https://registry.yarnpkg.com/whatwg-fetch/-/whatwg-fetch-2.0.3.tgz#9c84ec2dcf68187ff00bc64e1274b442176e1c84"
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/whatwg-fetch/-/whatwg-fetch-2.0.4.tgz#dde6a5df315f9d39991aa17621853d720b85566f"

 whet.extend@~0.9.9:
  version "0.9.9"
--- a/dashboard/dashboard.go
+++ b/dashboard/dashboard.go
@@ -32,12 +32,15 @@ import (
 	"sync/atomic"
 	"time"

+	"io"
+
 	"github.com/elastic/gosigar"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/mohae/deepcopy"
 	"golang.org/x/net/websocket"
 )

@@ -60,10 +63,11 @@ type Dashboard struct {

 	listener net.Listener
 	conns    map[uint32]*client // Currently live websocket connections
-	charts   *SystemMessage
-	commit   string
+	history  *Message
 	lock     sync.RWMutex // Lock protecting the dashboard's internals

+	logdir string
+
 	quit chan chan error // Channel used for graceful exit
 	wg   sync.WaitGroup
 }
@@ -71,30 +75,39 @@ type Dashboard struct {
 // client represents active websocket connection with a remote browser.
 type client struct {
 	conn   *websocket.Conn // Particular live websocket connection
-	msg    chan Message    // Message queue for the update messages
+	msg    chan *Message   // Message queue for the update messages
 	logger log.Logger      // Logger for the particular live websocket connection
 }

 // New creates a new dashboard instance with the given configuration.
-func New(config *Config, commit string) (*Dashboard, error) {
+func New(config *Config, commit string, logdir string) *Dashboard {
 	now := time.Now()
-	db := &Dashboard{
+	versionMeta := ""
+	if len(params.VersionMeta) > 0 {
+		versionMeta = fmt.Sprintf(" (%s)", params.VersionMeta)
+	}
+	return &Dashboard{
 		conns:  make(map[uint32]*client),
 		config: config,
 		quit:   make(chan chan error),
-		charts: &SystemMessage{
-			ActiveMemory:   emptyChartEntries(now, activeMemorySampleLimit, config.Refresh),
-			VirtualMemory:  emptyChartEntries(now, virtualMemorySampleLimit, config.Refresh),
-			NetworkIngress: emptyChartEntries(now, networkIngressSampleLimit, config.Refresh),
-			NetworkEgress:  emptyChartEntries(now, networkEgressSampleLimit, config.Refresh),
-			ProcessCPU:     emptyChartEntries(now, processCPUSampleLimit, config.Refresh),
-			SystemCPU:      emptyChartEntries(now, systemCPUSampleLimit, config.Refresh),
-			DiskRead:       emptyChartEntries(now, diskReadSampleLimit, config.Refresh),
-			DiskWrite:      emptyChartEntries(now, diskWriteSampleLimit, config.Refresh),
+		history: &Message{
+			General: &GeneralMessage{
+				Commit:  commit,
+				Version: fmt.Sprintf("v%d.%d.%d%s", params.VersionMajor, params.VersionMinor, params.VersionPatch, versionMeta),
+			},
+			System: &SystemMessage{
+				ActiveMemory:   emptyChartEntries(now, activeMemorySampleLimit, config.Refresh),
+				VirtualMemory:  emptyChartEntries(now, virtualMemorySampleLimit, config.Refresh),
+				NetworkIngress: emptyChartEntries(now, networkIngressSampleLimit, config.Refresh),
+				NetworkEgress:  emptyChartEntries(now, networkEgressSampleLimit, config.Refresh),
+				ProcessCPU:     emptyChartEntries(now, processCPUSampleLimit, config.Refresh),
+				SystemCPU:      emptyChartEntries(now, systemCPUSampleLimit, config.Refresh),
+				DiskRead:       emptyChartEntries(now, diskReadSampleLimit, config.Refresh),
+				DiskWrite:      emptyChartEntries(now, diskWriteSampleLimit, config.Refresh),
+			},
 		},
-		commit: commit,
+		logdir: logdir,
 	}
-	return db, nil
 }

 // emptyChartEntries returns a ChartEntry array containing limit number of empty samples.
@@ -108,19 +121,20 @@ func emptyChartEntries(t time.Time, limit int, refresh time.Duration) ChartEntri
 	return ce
 }

-// Protocols is a meaningless implementation of node.Service.
+// Protocols implements the node.Service interface.
 func (db *Dashboard) Protocols() []p2p.Protocol { return nil }

-// APIs is a meaningless implementation of node.Service.
+// APIs implements the node.Service interface.
 func (db *Dashboard) APIs() []rpc.API { return nil }

-// Start implements node.Service, starting the data collection thread and the listening server of the dashboard.
+// Start starts the data collection thread and the listening server of the dashboard.
+// Implements the node.Service interface.
 func (db *Dashboard) Start(server *p2p.Server) error {
 	log.Info("Starting dashboard")

 	db.wg.Add(2)
 	go db.collectData()
-	go db.collectLogs() // In case of removing this line change 2 back to 1 in wg.Add.
+	go db.streamLogs()

 	http.HandleFunc("/", db.webHandler)
 	http.Handle("/api", websocket.Handler(db.apiHandler))
@@ -136,7 +150,8 @@ func (db *Dashboard) Start(server *p2p.Server) error {
 	return nil
 }

-// Stop implements node.Service, stopping the data collection thread and the connection listener of the dashboard.
+// Stop stops the data collection thread and the connection listener of the dashboard.
+// Implements the node.Service interface.
 func (db *Dashboard) Stop() error {
 	// Close the connection listener.
 	var errs []error
@@ -194,7 +209,7 @@ func (db *Dashboard) apiHandler(conn *websocket.Conn) {
 	id := atomic.AddUint32(&nextID, 1)
 	client := &client{
 		conn:   conn,
-		msg:    make(chan Message, 128),
+		msg:    make(chan *Message, 128),
 		logger: log.New("id", id),
 	}
 	done := make(chan struct{})
@@ -218,29 +233,10 @@ func (db *Dashboard) apiHandler(conn *websocket.Conn) {
 		}
 	}()

-	versionMeta := ""
-	if len(params.VersionMeta) > 0 {
-		versionMeta = fmt.Sprintf(" (%s)", params.VersionMeta)
-	}
-	// Send the past data.
-	client.msg <- Message{
-		General: &GeneralMessage{
-			Version: fmt.Sprintf("v%d.%d.%d%s", params.VersionMajor, params.VersionMinor, params.VersionPatch, versionMeta),
-			Commit:  db.commit,
-		},
-		System: &SystemMessage{
-			ActiveMemory:   db.charts.ActiveMemory,
-			VirtualMemory:  db.charts.VirtualMemory,
-			NetworkIngress: db.charts.NetworkIngress,
-			NetworkEgress:  db.charts.NetworkEgress,
-			ProcessCPU:     db.charts.ProcessCPU,
-			SystemCPU:      db.charts.SystemCPU,
-			DiskRead:       db.charts.DiskRead,
-			DiskWrite:      db.charts.DiskWrite,
-		},
-	}
-	// Start tracking the connection and drop at connection loss.
 	db.lock.Lock()
+	// Send the past data.
+	client.msg <- deepcopy.Copy(db.history).(*Message)
+	// Start tracking the connection and drop at connection loss.
 	db.conns[id] = client
 	db.lock.Unlock()
 	defer func() {
@@ -249,29 +245,53 @@ func (db *Dashboard) apiHandler(conn *websocket.Conn) {
 		db.lock.Unlock()
 	}()
 	for {
-		fail := []byte{}
-		if _, err := conn.Read(fail); err != nil {
+		r := new(Request)
+		if err := websocket.JSON.Receive(conn, r); err != nil {
+			if err != io.EOF {
+				client.logger.Warn("Failed to receive request", "err", err)
+			}
 			close(done)
 			return
 		}
-		// Ignore all messages
+		if r.Logs != nil {
+			db.handleLogRequest(r.Logs, client)
+		}
+	}
+}
+
+// meterCollector returns a function, which retrieves a specific meter.
+func meterCollector(name string) func() int64 {
+	if metric := metrics.DefaultRegistry.Get(name); metric != nil {
+		m := metric.(metrics.Meter)
+		return func() int64 {
+			return m.Count()
+		}
+	}
+	return func() int64 {
+		return 0
 	}
 }

 // collectData collects the required data to plot on the dashboard.
 func (db *Dashboard) collectData() {
 	defer db.wg.Done()
+
 	systemCPUUsage := gosigar.Cpu{}
 	systemCPUUsage.Get()
 	var (
 		mem runtime.MemStats

-		prevNetworkIngress = metrics.DefaultRegistry.Get("p2p/InboundTraffic").(metrics.Meter).Count()
-		prevNetworkEgress  = metrics.DefaultRegistry.Get("p2p/OutboundTraffic").(metrics.Meter).Count()
+		collectNetworkIngress = meterCollector("p2p/InboundTraffic")
+		collectNetworkEgress  = meterCollector("p2p/OutboundTraffic")
+		collectDiskRead       = meterCollector("eth/db/chaindata/disk/read")
+		collectDiskWrite      = meterCollector("eth/db/chaindata/disk/write")
+
+		prevNetworkIngress = collectNetworkIngress()
+		prevNetworkEgress  = collectNetworkEgress()
 		prevProcessCPUTime = getProcessCPUTime()
 		prevSystemCPUUsage = systemCPUUsage
-		prevDiskRead       = metrics.DefaultRegistry.Get("eth/db/chaindata/disk/read").(metrics.Meter).Count()
-		prevDiskWrite      = metrics.DefaultRegistry.Get("eth/db/chaindata/disk/write").(metrics.Meter).Count()
+		prevDiskRead       = collectDiskRead()
+		prevDiskWrite      = collectDiskWrite()

 		frequency = float64(db.config.Refresh / time.Second)
 		numCPU    = float64(runtime.NumCPU())
@@ -285,12 +305,12 @@ func (db *Dashboard) collectData() {
 		case <-time.After(db.config.Refresh):
 			systemCPUUsage.Get()
 			var (
-				curNetworkIngress = metrics.DefaultRegistry.Get("p2p/InboundTraffic").(metrics.Meter).Count()
-				curNetworkEgress  = metrics.DefaultRegistry.Get("p2p/OutboundTraffic").(metrics.Meter).Count()
+				curNetworkIngress = collectNetworkIngress()
+				curNetworkEgress  = collectNetworkEgress()
 				curProcessCPUTime = getProcessCPUTime()
 				curSystemCPUUsage = systemCPUUsage
-				curDiskRead       = metrics.DefaultRegistry.Get("eth/db/chaindata/disk/read").(metrics.Meter).Count()
-				curDiskWrite      = metrics.DefaultRegistry.Get("eth/db/chaindata/disk/write").(metrics.Meter).Count()
+				curDiskRead       = collectDiskRead()
+				curDiskWrite      = collectDiskWrite()

 				deltaNetworkIngress = float64(curNetworkIngress - prevNetworkIngress)
 				deltaNetworkEgress  = float64(curNetworkEgress - prevNetworkEgress)
@@ -341,14 +361,17 @@ func (db *Dashboard) collectData() {
 				Time:  now,
 				Value: float64(deltaDiskWrite) / frequency,
 			}
-			db.charts.ActiveMemory = append(db.charts.ActiveMemory[1:], activeMemory)
-			db.charts.VirtualMemory = append(db.charts.VirtualMemory[1:], virtualMemory)
-			db.charts.NetworkIngress = append(db.charts.NetworkIngress[1:], networkIngress)
-			db.charts.NetworkEgress = append(db.charts.NetworkEgress[1:], networkEgress)
-			db.charts.ProcessCPU = append(db.charts.ProcessCPU[1:], processCPU)
-			db.charts.SystemCPU = append(db.charts.SystemCPU[1:], systemCPU)
-			db.charts.DiskRead = append(db.charts.DiskRead[1:], diskRead)
-			db.charts.DiskWrite = append(db.charts.DiskRead[1:], diskWrite)
+			sys := db.history.System
+			db.lock.Lock()
+			sys.ActiveMemory = append(sys.ActiveMemory[1:], activeMemory)
+			sys.VirtualMemory = append(sys.VirtualMemory[1:], virtualMemory)
+			sys.NetworkIngress = append(sys.NetworkIngress[1:], networkIngress)
+			sys.NetworkEgress = append(sys.NetworkEgress[1:], networkEgress)
+			sys.ProcessCPU = append(sys.ProcessCPU[1:], processCPU)
+			sys.SystemCPU = append(sys.SystemCPU[1:], systemCPU)
+			sys.DiskRead = append(sys.DiskRead[1:], diskRead)
+			sys.DiskWrite = append(sys.DiskRead[1:], diskWrite)
+			db.lock.Unlock()

 			db.sendToAll(&Message{
 				System: &SystemMessage{
@@ -366,34 +389,12 @@ func (db *Dashboard) collectData() {
 	}
 }

-// collectLogs collects and sends the logs to the active dashboards.
-func (db *Dashboard) collectLogs() {
-	defer db.wg.Done()
-
-	id := 1
-	// TODO (kurkomisi): log collection comes here.
-	for {
-		select {
-		case errc := <-db.quit:
-			errc <- nil
-			return
-		case <-time.After(db.config.Refresh / 2):
-			db.sendToAll(&Message{
-				Logs: &LogsMessage{
-					Log: []string{fmt.Sprintf("%-4d: This is a fake log.", id)},
-				},
-			})
-			id++
-		}
-	}
-}
-
 // sendToAll sends the given message to the active dashboards.
 func (db *Dashboard) sendToAll(msg *Message) {
 	db.lock.Lock()
 	for _, c := range db.conns {
 		select {
-		case c.msg <- *msg:
+		case c.msg <- msg:
 		default:
 			c.conn.Close()
 		}
--- a/dashboard/log.go
+++ b/dashboard/log.go
@@ -0,0 +1,288 @@
+// 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/>.
+
+package dashboard
+
+import (
+	"bytes"
+	"encoding/json"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/mohae/deepcopy"
+	"github.com/rjeczalik/notify"
+)
+
+var emptyChunk = json.RawMessage("[]")
+
+// prepLogs creates a JSON array from the given log record buffer.
+// Returns the prepared array and the position of the last '\n'
+// character in the original buffer, or -1 if it doesn't contain any.
+func prepLogs(buf []byte) (json.RawMessage, int) {
+	b := make(json.RawMessage, 1, len(buf)+1)
+	b[0] = '['
+	b = append(b, buf...)
+	last := -1
+	for i := 1; i < len(b); i++ {
+		if b[i] == '\n' {
+			b[i] = ','
+			last = i
+		}
+	}
+	if last < 0 {
+		return emptyChunk, -1
+	}
+	b[last] = ']'
+	return b[:last+1], last - 1
+}
+
+// handleLogRequest searches for the log file specified by the timestamp of the
+// request, creates a JSON array out of it and sends it to the requesting client.
+func (db *Dashboard) handleLogRequest(r *LogsRequest, c *client) {
+	files, err := ioutil.ReadDir(db.logdir)
+	if err != nil {
+		log.Warn("Failed to open logdir", "path", db.logdir, "err", err)
+		return
+	}
+	re := regexp.MustCompile(`\.log$`)
+	fileNames := make([]string, 0, len(files))
+	for _, f := range files {
+		if f.Mode().IsRegular() && re.MatchString(f.Name()) {
+			fileNames = append(fileNames, f.Name())
+		}
+	}
+	if len(fileNames) < 1 {
+		log.Warn("No log files in logdir", "path", db.logdir)
+		return
+	}
+	idx := sort.Search(len(fileNames), func(idx int) bool {
+		// Returns the smallest index such as fileNames[idx] >= r.Name,
+		// if there is no such index, returns n.
+		return fileNames[idx] >= r.Name
+	})
+
+	switch {
+	case idx < 0:
+		return
+	case idx == 0 && r.Past:
+		return
+	case idx >= len(fileNames):
+		return
+	case r.Past:
+		idx--
+	case idx == len(fileNames)-1 && fileNames[idx] == r.Name:
+		return
+	case idx == len(fileNames)-1 || (idx == len(fileNames)-2 && fileNames[idx] == r.Name):
+		// The last file is continuously updated, and its chunks are streamed,
+		// so in order to avoid log record duplication on the client side, it is
+		// handled differently. Its actual content is always saved in the history.
+		db.lock.Lock()
+		if db.history.Logs != nil {
+			c.msg <- &Message{
+				Logs: db.history.Logs,
+			}
+		}
+		db.lock.Unlock()
+		return
+	case fileNames[idx] == r.Name:
+		idx++
+	}
+
+	path := filepath.Join(db.logdir, fileNames[idx])
+	var buf []byte
+	if buf, err = ioutil.ReadFile(path); err != nil {
+		log.Warn("Failed to read file", "path", path, "err", err)
+		return
+	}
+	chunk, end := prepLogs(buf)
+	if end < 0 {
+		log.Warn("The file doesn't contain valid logs", "path", path)
+		return
+	}
+	c.msg <- &Message{
+		Logs: &LogsMessage{
+			Source: &LogFile{
+				Name: fileNames[idx],
+				Last: r.Past && idx == 0,
+			},
+			Chunk: chunk,
+		},
+	}
+}
+
+// streamLogs watches the file system, and when the logger writes
+// the new log records into the files, picks them up, then makes
+// JSON array out of them and sends them to the clients.
+func (db *Dashboard) streamLogs() {
+	defer db.wg.Done()
+	var (
+		err  error
+		errc chan error
+	)
+	defer func() {
+		if errc == nil {
+			errc = <-db.quit
+		}
+		errc <- err
+	}()
+
+	files, err := ioutil.ReadDir(db.logdir)
+	if err != nil {
+		log.Warn("Failed to open logdir", "path", db.logdir, "err", err)
+		return
+	}
+	var (
+		opened *os.File // File descriptor for the opened active log file.
+		buf    []byte   // Contains the recently written log chunks, which are not sent to the clients yet.
+	)
+
+	// The log records are always written into the last file in alphabetical order, because of the timestamp.
+	re := regexp.MustCompile(`\.log$`)
+	i := len(files) - 1
+	for i >= 0 && (!files[i].Mode().IsRegular() || !re.MatchString(files[i].Name())) {
+		i--
+	}
+	if i < 0 {
+		log.Warn("No log files in logdir", "path", db.logdir)
+		return
+	}
+	if opened, err = os.OpenFile(filepath.Join(db.logdir, files[i].Name()), os.O_RDONLY, 0600); err != nil {
+		log.Warn("Failed to open file", "name", files[i].Name(), "err", err)
+		return
+	}
+	defer opened.Close() // Close the lastly opened file.
+	fi, err := opened.Stat()
+	if err != nil {
+		log.Warn("Problem with file", "name", opened.Name(), "err", err)
+		return
+	}
+	db.lock.Lock()
+	db.history.Logs = &LogsMessage{
+		Source: &LogFile{
+			Name: fi.Name(),
+			Last: true,
+		},
+		Chunk: emptyChunk,
+	}
+	db.lock.Unlock()
+
+	watcher := make(chan notify.EventInfo, 10)
+	if err := notify.Watch(db.logdir, watcher, notify.Create); err != nil {
+		log.Warn("Failed to create file system watcher", "err", err)
+		return
+	}
+	defer notify.Stop(watcher)
+
+	ticker := time.NewTicker(db.config.Refresh)
+	defer ticker.Stop()
+
+loop:
+	for err == nil || errc == nil {
+		select {
+		case event := <-watcher:
+			// Make sure that new log file was created.
+			if !re.Match([]byte(event.Path())) {
+				break
+			}
+			if opened == nil {
+				log.Warn("The last log file is not opened")
+				break loop
+			}
+			// The new log file's name is always greater,
+			// because it is created using the actual log record's time.
+			if opened.Name() >= event.Path() {
+				break
+			}
+			// Read the rest of the previously opened file.
+			chunk, err := ioutil.ReadAll(opened)
+			if err != nil {
+				log.Warn("Failed to read file", "name", opened.Name(), "err", err)
+				break loop
+			}
+			buf = append(buf, chunk...)
+			opened.Close()
+
+			if chunk, last := prepLogs(buf); last >= 0 {
+				// Send the rest of the previously opened file.
+				db.sendToAll(&Message{
+					Logs: &LogsMessage{
+						Chunk: chunk,
+					},
+				})
+			}
+			if opened, err = os.OpenFile(event.Path(), os.O_RDONLY, 0644); err != nil {
+				log.Warn("Failed to open file", "name", event.Path(), "err", err)
+				break loop
+			}
+			buf = buf[:0]
+
+			// Change the last file in the history.
+			fi, err := opened.Stat()
+			if err != nil {
+				log.Warn("Problem with file", "name", opened.Name(), "err", err)
+				break loop
+			}
+			db.lock.Lock()
+			db.history.Logs.Source.Name = fi.Name()
+			db.history.Logs.Chunk = emptyChunk
+			db.lock.Unlock()
+		case <-ticker.C: // Send log updates to the client.
+			if opened == nil {
+				log.Warn("The last log file is not opened")
+				break loop
+			}
+			// Read the new logs created since the last read.
+			chunk, err := ioutil.ReadAll(opened)
+			if err != nil {
+				log.Warn("Failed to read file", "name", opened.Name(), "err", err)
+				break loop
+			}
+			b := append(buf, chunk...)
+
+			chunk, last := prepLogs(b)
+			if last < 0 {
+				break
+			}
+			// Only keep the invalid part of the buffer, which can be valid after the next read.
+			buf = b[last+1:]
+
+			var l *LogsMessage
+			// Update the history.
+			db.lock.Lock()
+			if bytes.Equal(db.history.Logs.Chunk, emptyChunk) {
+				db.history.Logs.Chunk = chunk
+				l = deepcopy.Copy(db.history.Logs).(*LogsMessage)
+			} else {
+				b = make([]byte, len(db.history.Logs.Chunk)+len(chunk)-1)
+				copy(b, db.history.Logs.Chunk)
+				b[len(db.history.Logs.Chunk)-1] = ','
+				copy(b[len(db.history.Logs.Chunk):], chunk[1:])
+				db.history.Logs.Chunk = b
+				l = &LogsMessage{Chunk: chunk}
+			}
+			db.lock.Unlock()
+
+			db.sendToAll(&Message{Logs: l})
+		case errc = <-db.quit:
+			break loop
+		}
+	}
+}
--- a/dashboard/message.go
+++ b/dashboard/message.go
@@ -16,7 +16,10 @@

 package dashboard

-import "time"
+import (
+	"encoding/json"
+	"time"
+)

 type Message struct {
 	General *GeneralMessage `json:"general,omitempty"`
@@ -67,6 +70,24 @@ type SystemMessage struct {
 	DiskWrite      ChartEntries `json:"diskWrite,omitempty"`
 }

+// LogsMessage wraps up a log chunk. If Source isn't present, the chunk is a stream chunk.
 type LogsMessage struct {
-	Log []string `json:"log,omitempty"`
+	Source *LogFile        `json:"source,omitempty"` // Attributes of the log file.
+	Chunk  json.RawMessage `json:"chunk"`            // Contains log records.
+}
+
+// LogFile contains the attributes of a log file.
+type LogFile struct {
+	Name string `json:"name"` // The name of the file.
+	Last bool   `json:"last"` // Denotes if the actual log file is the last one in the directory.
+}
+
+// Request represents the client request.
+type Request struct {
+	Logs *LogsRequest `json:"logs,omitempty"`
+}
+
+type LogsRequest struct {
+	Name string `json:"name"` // The request handler searches for log file based on this file name.
+	Past bool   `json:"past"` // Denotes whether the client wants the previous or the next file.
 }
--- a/internal/debug/flags.go
+++ b/internal/debug/flags.go
@@ -95,7 +95,10 @@ var Flags = []cli.Flag{
 	memprofilerateFlag, blockprofilerateFlag, cpuprofileFlag, traceFlag,
 }

-var glogger *log.GlogHandler
+var (
+	ostream log.Handler
+	glogger *log.GlogHandler
+)

 func init() {
 	usecolor := term.IsTty(os.Stderr.Fd()) && os.Getenv("TERM") != "dumb"
@@ -103,14 +106,26 @@ func init() {
 	if usecolor {
 		output = colorable.NewColorableStderr()
 	}
-	glogger = log.NewGlogHandler(log.StreamHandler(output, log.TerminalFormat(usecolor)))
+	ostream = log.StreamHandler(output, log.TerminalFormat(usecolor))
+	glogger = log.NewGlogHandler(ostream)
 }

 // Setup initializes profiling and logging based on the CLI flags.
 // It should be called as early as possible in the program.
-func Setup(ctx *cli.Context) error {
+func Setup(ctx *cli.Context, logdir string) error {
 	// logging
 	log.PrintOrigins(ctx.GlobalBool(debugFlag.Name))
+	if logdir != "" {
+		rfh, err := log.RotatingFileHandler(
+			logdir,
+			262144,
+			log.JSONFormatOrderedEx(false, true),
+		)
+		if err != nil {
+			return err
+		}
+		glogger.SetHandler(log.MultiHandler(ostream, rfh))
+	}
 	glogger.Verbosity(log.Lvl(ctx.GlobalInt(verbosityFlag.Name)))
 	glogger.Vmodule(ctx.GlobalString(vmoduleFlag.Name))
 	glogger.BacktraceAt(ctx.GlobalString(backtraceAtFlag.Name))
--- a/log/format.go
+++ b/log/format.go
@@ -77,11 +77,11 @@ type TerminalStringer interface {
 // a terminal with color-coded level output and terser human friendly timestamp.
 // This format should only be used for interactive programs or while developing.
 //
-//     [TIME] [LEVEL] MESAGE key=value key=value ...
+//     [LEVEL] [TIME] MESAGE key=value key=value ...
 //
 // Example:
 //
-//     [May 16 20:58:45] [DBUG] remove route ns=haproxy addr=127.0.0.1:50002
+//     [DBUG] [May 16 20:58:45] remove route ns=haproxy addr=127.0.0.1:50002
 //
 func TerminalFormat(usecolor bool) Format {
 	return FormatFunc(func(r *Record) []byte {
@@ -202,6 +202,48 @@ func JSONFormat() Format {
 	return JSONFormatEx(false, true)
 }

+// JSONFormatOrderedEx formats log records as JSON arrays. If pretty is true,
+// records will be pretty-printed. If lineSeparated is true, records
+// will be logged with a new line between each record.
+func JSONFormatOrderedEx(pretty, lineSeparated bool) Format {
+	jsonMarshal := json.Marshal
+	if pretty {
+		jsonMarshal = func(v interface{}) ([]byte, error) {
+			return json.MarshalIndent(v, "", "    ")
+		}
+	}
+	return FormatFunc(func(r *Record) []byte {
+		props := make(map[string]interface{})
+
+		props[r.KeyNames.Time] = r.Time
+		props[r.KeyNames.Lvl] = r.Lvl.String()
+		props[r.KeyNames.Msg] = r.Msg
+
+		ctx := make([]string, len(r.Ctx))
+		for i := 0; i < len(r.Ctx); i += 2 {
+			k, ok := r.Ctx[i].(string)
+			if !ok {
+				props[errorKey] = fmt.Sprintf("%+v is not a string key,", r.Ctx[i])
+			}
+			ctx[i] = k
+			ctx[i+1] = formatLogfmtValue(r.Ctx[i+1], true)
+		}
+		props[r.KeyNames.Ctx] = ctx
+
+		b, err := jsonMarshal(props)
+		if err != nil {
+			b, _ = jsonMarshal(map[string]string{
+				errorKey: err.Error(),
+			})
+			return b
+		}
+		if lineSeparated {
+			b = append(b, '\n')
+		}
+		return b
+	})
+}
+
 // JSONFormatEx formats log records as JSON objects. If pretty is true,
 // records will be pretty-printed. If lineSeparated is true, records
 // will be logged with a new line between each record.
--- a/log/handler.go
+++ b/log/handler.go
@@ -8,6 +8,11 @@ import (
 	"reflect"
 	"sync"

+	"io/ioutil"
+	"path/filepath"
+	"regexp"
+	"strings"
+
 	"github.com/go-stack/stack"
 )

@@ -70,6 +75,111 @@ func FileHandler(path string, fmtr Format) (Handler, error) {
 	return closingHandler{f, StreamHandler(f, fmtr)}, nil
 }

+// countingWriter wraps a WriteCloser object in order to count the written bytes.
+type countingWriter struct {
+	w     io.WriteCloser // the wrapped object
+	count uint           // number of bytes written
+}
+
+// Write increments the byte counter by the number of bytes written.
+// Implements the WriteCloser interface.
+func (w *countingWriter) Write(p []byte) (n int, err error) {
+	n, err = w.w.Write(p)
+	w.count += uint(n)
+	return n, err
+}
+
+// Close implements the WriteCloser interface.
+func (w *countingWriter) Close() error {
+	return w.w.Close()
+}
+
+// prepFile opens the log file at the given path, and cuts off the invalid part
+// from the end, because the previous execution could have been finished by interruption.
+// Assumes that every line ended by '\n' contains a valid log record.
+func prepFile(path string) (*countingWriter, error) {
+	f, err := os.OpenFile(path, os.O_RDWR|os.O_APPEND, 0600)
+	if err != nil {
+		return nil, err
+	}
+	_, err = f.Seek(-1, io.SeekEnd)
+	if err != nil {
+		return nil, err
+	}
+	buf := make([]byte, 1)
+	var cut int64
+	for {
+		if _, err := f.Read(buf); err != nil {
+			return nil, err
+		}
+		if buf[0] == '\n' {
+			break
+		}
+		if _, err = f.Seek(-2, io.SeekCurrent); err != nil {
+			return nil, err
+		}
+		cut++
+	}
+	fi, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	ns := fi.Size() - cut
+	if err = f.Truncate(ns); err != nil {
+		return nil, err
+	}
+	return &countingWriter{w: f, count: uint(ns)}, nil
+}
+
+// RotatingFileHandler returns a handler which writes log records to file chunks
+// at the given path. When a file's size reaches the limit, the handler creates
+// a new file named after the timestamp of the first log record it will contain.
+func RotatingFileHandler(path string, limit uint, formatter Format) (Handler, error) {
+	if err := os.MkdirAll(path, 0700); err != nil {
+		return nil, err
+	}
+	files, err := ioutil.ReadDir(path)
+	if err != nil {
+		return nil, err
+	}
+	re := regexp.MustCompile(`\.log$`)
+	last := len(files) - 1
+	for last >= 0 && (!files[last].Mode().IsRegular() || !re.MatchString(files[last].Name())) {
+		last--
+	}
+	var counter *countingWriter
+	if last >= 0 && files[last].Size() < int64(limit) {
+		// Open the last file, and continue to write into it until it's size reaches the limit.
+		if counter, err = prepFile(filepath.Join(path, files[last].Name())); err != nil {
+			return nil, err
+		}
+	}
+	if counter == nil {
+		counter = new(countingWriter)
+	}
+	h := StreamHandler(counter, formatter)
+
+	return FuncHandler(func(r *Record) error {
+		if counter.count > limit {
+			counter.Close()
+			counter.w = nil
+		}
+		if counter.w == nil {
+			f, err := os.OpenFile(
+				filepath.Join(path, fmt.Sprintf("%s.log", strings.Replace(r.Time.Format("060102150405.00"), ".", "", 1))),
+				os.O_CREATE|os.O_APPEND|os.O_WRONLY,
+				0600,
+			)
+			if err != nil {
+				return err
+			}
+			counter.w = f
+			counter.count = 0
+		}
+		return h.Log(r)
+	}), nil
+}
+
 // NetHandler opens a socket to the given address and writes records
 // over the connection.
 func NetHandler(network, addr string, fmtr Format) (Handler, error) {
--- a/log/handler_glog.go
+++ b/log/handler_glog.go
@@ -57,6 +57,11 @@ func NewGlogHandler(h Handler) *GlogHandler {
 	}
 }

+// SetHandler updates the handler to write records to the specified sub-handler.
+func (h *GlogHandler) SetHandler(nh Handler) {
+	h.origin = nh
+}
+
 // pattern contains a filter for the Vmodule option, holding a verbosity level
 // and a file pattern to match.
 type pattern struct {
--- a/log/logger.go
+++ b/log/logger.go
@@ -11,6 +11,7 @@ import (
 const timeKey = "t"
 const lvlKey = "lvl"
 const msgKey = "msg"
+const ctxKey = "ctx"
 const errorKey = "LOG15_ERROR"
 const skipLevel = 2

@@ -101,6 +102,7 @@ type RecordKeyNames struct {
 	Time string
 	Msg  string
 	Lvl  string
+	Ctx  string
 }

 // A Logger writes key/value pairs to a Handler
@@ -139,6 +141,7 @@ func (l *logger) write(msg string, lvl Lvl, ctx []interface{}, skip int) {
 			Time: timeKey,
 			Msg:  msgKey,
 			Lvl:  lvlKey,
+			Ctx:  ctxKey,
 		},
 	})
 }
--- a/node/config.go
+++ b/node/config.go
@@ -179,7 +179,7 @@ func (c *Config) NodeDB() string {
 	if c.DataDir == "" {
 		return "" // ephemeral
 	}
-	return c.resolvePath(datadirNodeDatabase)
+	return c.ResolvePath(datadirNodeDatabase)
 }

 // DefaultIPCEndpoint returns the IPC path used by default.
@@ -262,8 +262,8 @@ var isOldGethResource = map[string]bool{
 	"trusted-nodes.json": true,
 }

-// resolvePath resolves path in the instance directory.
-func (c *Config) resolvePath(path string) string {
+// ResolvePath resolves path in the instance directory.
+func (c *Config) ResolvePath(path string) string {
 	if filepath.IsAbs(path) {
 		return path
 	}
@@ -309,7 +309,7 @@ func (c *Config) NodeKey() *ecdsa.PrivateKey {
 		return key
 	}

-	keyfile := c.resolvePath(datadirPrivateKey)
+	keyfile := c.ResolvePath(datadirPrivateKey)
 	if key, err := crypto.LoadECDSA(keyfile); err == nil {
 		return key
 	}
@@ -332,12 +332,12 @@ func (c *Config) NodeKey() *ecdsa.PrivateKey {

 // StaticNodes returns a list of node enode URLs configured as static nodes.
 func (c *Config) StaticNodes() []*discover.Node {
-	return c.parsePersistentNodes(c.resolvePath(datadirStaticNodes))
+	return c.parsePersistentNodes(c.ResolvePath(datadirStaticNodes))
 }

 // TrustedNodes returns a list of node enode URLs configured as trusted nodes.
 func (c *Config) TrustedNodes() []*discover.Node {
-	return c.parsePersistentNodes(c.resolvePath(datadirTrustedNodes))
+	return c.parsePersistentNodes(c.ResolvePath(datadirTrustedNodes))
 }

 // parsePersistentNodes parses a list of discovery node URLs loaded from a .json
--- a/node/node.go
+++ b/node/node.go
@@ -570,12 +570,12 @@ func (n *Node) OpenDatabase(name string, cache, handles int) (ethdb.Database, er
 	if n.config.DataDir == "" {
 		return ethdb.NewMemDatabase(), nil
 	}
-	return ethdb.NewLDBDatabase(n.config.resolvePath(name), cache, handles)
+	return ethdb.NewLDBDatabase(n.config.ResolvePath(name), cache, handles)
 }

 // ResolvePath returns the absolute path of a resource in the instance directory.
 func (n *Node) ResolvePath(x string) string {
-	return n.config.resolvePath(x)
+	return n.config.ResolvePath(x)
 }

 // apis returns the collection of RPC descriptors this node offers.
--- a/node/service.go
+++ b/node/service.go
@@ -43,7 +43,7 @@ func (ctx *ServiceContext) OpenDatabase(name string, cache int, handles int) (et
 	if ctx.config.DataDir == "" {
 		return ethdb.NewMemDatabase(), nil
 	}
-	db, err := ethdb.NewLDBDatabase(ctx.config.resolvePath(name), cache, handles)
+	db, err := ethdb.NewLDBDatabase(ctx.config.ResolvePath(name), cache, handles)
 	if err != nil {
 		return nil, err
 	}
@@ -54,7 +54,7 @@ func (ctx *ServiceContext) OpenDatabase(name string, cache int, handles int) (et
 // and if the user actually uses persistent storage. It will return an empty string
 // for emphemeral storage and the user's own input for absolute paths.
 func (ctx *ServiceContext) ResolvePath(path string) string {
-	return ctx.config.resolvePath(path)
+	return ctx.config.ResolvePath(path)
 }

 // Service retrieves a currently running service registered of a specific type.
--- a/vendor/github.com/mohae/deepcopy/LICENSE
+++ b/vendor/github.com/mohae/deepcopy/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Joel
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
--- a/vendor/github.com/mohae/deepcopy/README.md
+++ b/vendor/github.com/mohae/deepcopy/README.md
@@ -0,0 +1,8 @@
+deepCopy
+========
+[![GoDoc](https://godoc.org/github.com/mohae/deepcopy?status.svg)](https://godoc.org/github.com/mohae/deepcopy)[![Build Status](https://travis-ci.org/mohae/deepcopy.png)](https://travis-ci.org/mohae/deepcopy)
+
+DeepCopy makes deep copies of things: unexported field values are not copied.
+
+## Usage
+    cpy := deepcopy.Copy(orig)
--- a/vendor/github.com/mohae/deepcopy/deepcopy.go
+++ b/vendor/github.com/mohae/deepcopy/deepcopy.go
@@ -0,0 +1,125 @@
+// deepcopy makes deep copies of things. A standard copy will copy the
+// pointers: deep copy copies the values pointed to.  Unexported field
+// values are not copied.
+//
+// Copyright (c)2014-2016, Joel Scoble (github.com/mohae), all rights reserved.
+// License: MIT, for more details check the included LICENSE file.
+package deepcopy
+
+import (
+	"reflect"
+	"time"
+)
+
+// Interface for delegating copy process to type
+type Interface interface {
+	DeepCopy() interface{}
+}
+
+// Iface is an alias to Copy; this exists for backwards compatibility reasons.
+func Iface(iface interface{}) interface{} {
+	return Copy(iface)
+}
+
+// Copy creates a deep copy of whatever is passed to it and returns the copy
+// in an interface{}.  The returned value will need to be asserted to the
+// correct type.
+func Copy(src interface{}) interface{} {
+	if src == nil {
+		return nil
+	}
+
+	// Make the interface a reflect.Value
+	original := reflect.ValueOf(src)
+
+	// Make a copy of the same type as the original.
+	cpy := reflect.New(original.Type()).Elem()
+
+	// Recursively copy the original.
+	copyRecursive(original, cpy)
+
+	// Return the copy as an interface.
+	return cpy.Interface()
+}
+
+// copyRecursive does the actual copying of the interface. It currently has
+// limited support for what it can handle. Add as needed.
+func copyRecursive(original, cpy reflect.Value) {
+	// check for implement deepcopy.Interface
+	if original.CanInterface() {
+		if copier, ok := original.Interface().(Interface); ok {
+			cpy.Set(reflect.ValueOf(copier.DeepCopy()))
+			return
+		}
+	}
+
+	// handle according to original's Kind
+	switch original.Kind() {
+	case reflect.Ptr:
+		// Get the actual value being pointed to.
+		originalValue := original.Elem()
+
+		// if  it isn't valid, return.
+		if !originalValue.IsValid() {
+			return
+		}
+		cpy.Set(reflect.New(originalValue.Type()))
+		copyRecursive(originalValue, cpy.Elem())
+
+	case reflect.Interface:
+		// If this is a nil, don't do anything
+		if original.IsNil() {
+			return
+		}
+		// Get the value for the interface, not the pointer.
+		originalValue := original.Elem()
+
+		// Get the value by calling Elem().
+		copyValue := reflect.New(originalValue.Type()).Elem()
+		copyRecursive(originalValue, copyValue)
+		cpy.Set(copyValue)
+
+	case reflect.Struct:
+		t, ok := original.Interface().(time.Time)
+		if ok {
+			cpy.Set(reflect.ValueOf(t))
+			return
+		}
+		// Go through each field of the struct and copy it.
+		for i := 0; i < original.NumField(); i++ {
+			// The Type's StructField for a given field is checked to see if StructField.PkgPath
+			// is set to determine if the field is exported or not because CanSet() returns false
+			// for settable fields.  I'm not sure why.  -mohae
+			if original.Type().Field(i).PkgPath != "" {
+				continue
+			}
+			copyRecursive(original.Field(i), cpy.Field(i))
+		}
+
+	case reflect.Slice:
+		if original.IsNil() {
+			return
+		}
+		// Make a new slice and copy each element.
+		cpy.Set(reflect.MakeSlice(original.Type(), original.Len(), original.Cap()))
+		for i := 0; i < original.Len(); i++ {
+			copyRecursive(original.Index(i), cpy.Index(i))
+		}
+
+	case reflect.Map:
+		if original.IsNil() {
+			return
+		}
+		cpy.Set(reflect.MakeMap(original.Type()))
+		for _, key := range original.MapKeys() {
+			originalValue := original.MapIndex(key)
+			copyValue := reflect.New(originalValue.Type()).Elem()
+			copyRecursive(originalValue, copyValue)
+			copyKey := Copy(key.Interface())
+			cpy.SetMapIndex(reflect.ValueOf(copyKey), copyValue)
+		}
+
+	default:
+		cpy.Set(original)
+	}
+}
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -291,6 +291,12 @@
 			"revision": "ad45545899c7b13c020ea92b2072220eefad42b8",
 			"revisionTime": "2015-03-14T17:03:34Z"
 		},
+		{
+			"checksumSHA1": "2jsbDTvwxafPp7FJjJ8IIFlTLjs=",
+			"path": "github.com/mohae/deepcopy",
+			"revision": "c48cc78d482608239f6c4c92a4abd87eb8761c90",
+			"revisionTime": "2017-09-29T03:49:55Z"
+		},
 		{
 			"checksumSHA1": "FYM/8R2CqS6PSNAoKl6X5gNJ20A=",
 			"path": "github.com/naoina/toml",