From d235a6141229d84970ae74a796f9d62dc78c46ed Mon Sep 17 00:00:00 2001
From: Sean Larkin <sean.larkin@cuw.edu>
Date: Mon, 25 Dec 2017 21:12:08 -0600
Subject: [PATCH] feat(profiling): add profiling plugin

---
 lib/debug/ProfilingPlugin.js                  | 388 ++++++++++++++++++
 lib/webpack.js                                |   4 +
 package.json                                  |   1 +
 test/ProfilingPlugin.unittest.js              |  62 +++
 .../plugins/profiling-plugin/index.js         |  16 +
 .../profiling-plugin/webpack.config.js        |  16 +
 yarn.lock                                     |   4 +
 7 files changed, 491 insertions(+)
 create mode 100644 lib/debug/ProfilingPlugin.js
 create mode 100644 test/ProfilingPlugin.unittest.js
 create mode 100644 test/configCases/plugins/profiling-plugin/index.js
 create mode 100644 test/configCases/plugins/profiling-plugin/webpack.config.js

diff --git a/lib/debug/ProfilingPlugin.js b/lib/debug/ProfilingPlugin.js
new file mode 100644
index 000000000..375814f70
--- /dev/null
+++ b/lib/debug/ProfilingPlugin.js
@@ -0,0 +1,388 @@
+const fs = require("fs");
+const Trace = require("chrome-trace-event").Tracer;
+let inspector = undefined;
+
+try {
+	inspector = require("inspector"); // eslint-disable-line node/no-missing-require
+} catch(e) {
+	console.log("Unable to CPU profile in < node 8.0");
+}
+
+// TODO: Add this to webpack.js.org docs for this plugin, and for profiling build times
+/**
+ * How this plugin works: (placeholder until in docs)
+ *
+ * In chrome, open the `Profile Tab`, when you run webpack,
+ * this plugin will output an events.json file that you
+ * can drag and drop into the profiler. It will then display timeline stats and calls per plugin!
+ *
+ * Example: https://chromedevtools.github.io/timeline-viewer/?url=https%3A%2F%2Fgist.githubusercontent.com%2FTheLarkInn%2Fb94b728fa5e22f62c312e110a9944768%2Fraw%2Fcb672fb3f661a17576803e41db6030382b1a0fc9%2Fevents.json&loadTimelineFromURL=drive://163GY-H0wvF9rSrlwjJcrdTL-YLnppp55
+ */
+
+class Profiler {
+	constructor(inspector) {
+		this.session = undefined;
+		this.inspector = inspector;
+	}
+
+	hasSession() {
+		return this.session !== undefined;
+	}
+
+	startProfiling() {
+		if(this.inspector === undefined) {
+			return Promise.resolve();
+		}
+
+		try {
+			this.session = new inspector.Session();
+			this.session.connect();
+		} catch(_) {
+			this.session = undefined;
+			return Promise.resolve();
+		}
+
+		return Promise.all([
+			this.sendCommand("Profiler.setSamplingInterval", {
+				interval: 100
+			}),
+			this.sendCommand("Profiler.enable"),
+			this.sendCommand("Profiler.start"),
+		]);
+	}
+
+	sendCommand(method, params) {
+		if(this.hasSession()) {
+			return new Promise((res, rej) => {
+				return this.session.post(method, params, (err, params) => {
+					if(err !== null) {
+						rej(err);
+					} else {
+						res(params);
+					}
+				});
+			});
+		} else {
+			return Promise.resolve();
+		}
+	}
+
+	destroy() {
+		if(this.hasSession()) {
+			this.session.disconnect();
+		}
+
+		return Promise.resolve();
+	}
+
+	stopProfiling() {
+		return this.sendCommand("Profiler.stop");
+	}
+}
+
+/**
+ * @param {string} outPath The location where to write the log.
+ * @returns {{trace: ?,	counter: number, profiler: Profiler}} The trace object
+ */
+function createTrace(outPath) {
+	const trace = new Trace({
+		noStream: true
+	});
+	const profiler = new Profiler(inspector);
+
+	let counter = 0;
+
+	trace.pipe(fs.createWriteStream(outPath));
+	// These are critical events that need to be inserted so that tools like
+	// chrome dev tools can load the profile.
+	trace.instantEvent({
+		name: "TracingStartedInPage",
+		id: ++counter,
+		cat: ["disabled-by-default-devtools.timeline"],
+		args: {
+			data: {
+				sessionId: "-1",
+				page: "0xfff",
+				frames: [{
+					frame: "0xfff",
+					url: "webpack",
+					name: ""
+				}]
+			}
+		}
+	});
+
+	trace.instantEvent({
+		name: "TracingStartedInBrowser",
+		id: ++counter,
+		cat: ["disabled-by-default-devtools.timeline"],
+		args: {
+			data: {
+				sessionId: "-1"
+			},
+		}
+	});
+
+	return {
+		trace,
+		counter,
+		profiler
+	};
+}
+
+class ProfilingPlugin {
+	// TODO: Add plugin schema validation here since there are options.
+	constructor(opts) {
+		opts = opts || {};
+		this.outPath = opts.outPath || "events.json";
+	}
+
+	apply(compiler) {
+		const tracer = createTrace(this.outPath);
+		tracer.profiler.startProfiling();
+
+		// Compiler Hooks
+		Object.keys(compiler.hooks).forEach(hookName => {
+			compiler.hooks[hookName].intercept(makeInterceptorFor("Compiler", tracer)(hookName));
+		});
+
+		Object.keys(compiler.resolverFactory.hooks).forEach(hookName => {
+			compiler.resolverFactory.hooks[hookName].intercept(makeInterceptorFor("Resolver", tracer)(hookName));
+		});
+
+		compiler.hooks.compilation.tap("ProfilingPlugin", (compilation, {
+			normalModuleFactory,
+			contextModuleFactory
+		}) => {
+			interceptAllHooksFor(compilation, tracer, "Compilation");
+			interceptAllHooksFor(normalModuleFactory, tracer, "Normal Module Factory");
+			interceptAllHooksFor(contextModuleFactory, tracer, "Context Module Factory");
+			interceptAllParserHooks(normalModuleFactory, tracer);
+			interceptTemplateInstancesFrom(compilation, tracer);
+		});
+
+		// We need to write out the CPU profile when we are all done.
+		compiler.hooks.done.tap({
+			name: "ProfilingPlugin",
+			stage: Infinity
+		}, () => {
+			tracer.profiler.stopProfiling().then((parsedResults) => {
+
+				if(parsedResults === undefined) {
+					tracer.profiler.destroy();
+					tracer.trace.flush();
+					return;
+				}
+
+				const cpuStartTime = parsedResults.profile.startTime;
+				const cpuEndTime = parsedResults.profile.endTime;
+
+				tracer.trace.completeEvent({
+					name: "TaskQueueManager::ProcessTaskFromWorkQueue",
+					id: ++tracer.counter,
+					cat: ["toplevel"],
+					ts: cpuStartTime,
+					args: {
+						src_file: "../../ipc/ipc_moji_bootstrap.cc",
+						src_func: "Accept"
+					}
+				});
+
+				tracer.trace.completeEvent({
+					name: "EvaluateScript",
+					id: ++tracer.counter,
+					cat: ["devtools.timeline"],
+					ts: cpuStartTime,
+					dur: cpuEndTime - cpuStartTime,
+					args: {
+						data: {
+							url: "webpack",
+							lineNumber: 1,
+							columnNumber: 1,
+							frame: "0xFFF"
+						}
+					}
+				});
+
+				tracer.trace.instantEvent({
+					name: "CpuProfile",
+					id: ++tracer.counter,
+					cat: ["disabled-by-default-devtools.timeline"],
+					ts: cpuEndTime,
+					args: {
+						data: {
+							cpuProfile: parsedResults.profile
+						}
+					}
+				});
+
+				tracer.profiler.destroy();
+				tracer.trace.flush();
+			});
+		});
+	}
+}
+
+const interceptTemplateInstancesFrom = (compilation, tracer) => {
+	const {
+		mainTemplate,
+		chunkTemplate,
+		hotUpdateChunkTemplate,
+		moduleTemplates
+	} = compilation;
+
+	const {
+		javascript,
+		webassembly
+	} = moduleTemplates;
+
+	[{
+			instance: mainTemplate,
+			name: "MainTemplate"
+		},
+		{
+			instance: chunkTemplate,
+			name: "ChunkTemplate"
+		},
+		{
+			instance: hotUpdateChunkTemplate,
+			name: "HotUpdateChunkTemplate"
+		},
+		{
+			instance: javascript,
+			name: "JavaScriptModuleTemplate"
+		},
+		{
+			instance: webassembly,
+			name: "WebAssemblyModuleTemplate"
+		}
+	].forEach(templateObject => {
+		Object.keys(templateObject.instance.hooks).forEach(hookName => {
+			templateObject.instance.hooks[hookName].intercept(makeInterceptorFor(templateObject.name, tracer)(hookName));
+		});
+	});
+};
+
+const interceptAllHooksFor = (instance, tracer, logLabel) => {
+	Object.keys(instance.hooks).forEach(hookName => {
+		instance.hooks[hookName].intercept(makeInterceptorFor(logLabel, tracer)(hookName));
+	});
+};
+
+const interceptAllParserHooks = (moduleFactory, tracer) => {
+	const moduleTypes = [
+		"javascript/auto",
+		"javascript/dynamic",
+		"javascript/esm",
+		"json",
+		"webassembly/experimental"
+	];
+
+	moduleTypes.forEach(moduleType => {
+		moduleFactory.hooks.parser.for(moduleType).tap("ProfilingPlugin", (parser, parserOpts) => {
+			interceptAllHooksFor(parser, tracer, "Parser");
+		});
+	});
+};
+
+const makeInterceptorFor = (instance, tracer) => (hookName) => ({
+	register: ({
+		name,
+		type,
+		fn
+	}) => {
+		const newFn = makeNewProfiledTapFn(hookName, tracer, {
+			name,
+			type,
+			fn
+		});
+		return({ // eslint-disable-line
+			name,
+			type,
+			fn: newFn
+		});
+	}
+});
+
+/**
+ * @param {string} hookName Name of the hook to profile.
+ * @param {{counter: number, trace: *, profiler: *}} tracer Instance of tracer.
+ * @param {{name: string, type: string, fn: Function}} opts Options for the profiled fn.
+ * @returns {*} Chainable hooked function.
+ */
+const makeNewProfiledTapFn = (hookName, tracer, {
+	name,
+	type,
+	fn
+}) => {
+	const defaultCategory = ["blink.user_timing"];
+
+	switch(type) {
+		case "promise":
+			return(...args) => { // eslint-disable-line
+				const id = ++tracer.counter;
+				tracer.trace.begin({
+					name,
+					id,
+					cat: defaultCategory
+				});
+				return fn(...args).then(r => {
+					tracer.trace.end({
+						name,
+						id,
+						cat: defaultCategory
+					});
+					return r;
+				});
+			};
+		case "async":
+			return(...args) => { // eslint-disable-line
+				const id = ++tracer.counter;
+				tracer.trace.begin({
+					name,
+					id,
+					cat: defaultCategory
+				});
+				fn(...args, (...r) => {
+					const callback = args.pop();
+					tracer.trace.end({
+						name,
+						id,
+						cat: defaultCategory
+					});
+					callback(...r);
+				});
+			};
+		case "sync":
+			return(...args) => { // eslint-disable-line
+				const id = ++tracer.counter;
+				tracer.trace.begin({
+					name,
+					id,
+					cat: defaultCategory
+				});
+				let r;
+				try {
+					r = fn(...args);
+				} catch(error) {
+					tracer.trace.end({
+						name,
+						id,
+						cat: defaultCategory
+					});
+					throw error;
+				}
+				tracer.trace.end({
+					name,
+					id,
+					cat: defaultCategory
+				});
+				return r;
+			};
+		default:
+			break;
+	}
+};
+
+module.exports = ProfilingPlugin;
+module.exports.Profiler = Profiler;
diff --git a/lib/webpack.js b/lib/webpack.js
index 27f76a21c..322dbf041 100644
--- a/lib/webpack.js
+++ b/lib/webpack.js
@@ -123,3 +123,7 @@ exportPlugins(exports.node = {}, {
 	"NodeTemplatePlugin": () => require("./node/NodeTemplatePlugin"),
 	"ReadFileCompileWasmTemplatePlugin": () => require("./node/ReadFileCompileWasmTemplatePlugin"),
 });
+
+exportPlugins(exports.debug = {}, {
+	"ProfilingPlugin": () => require("./debug/ProfilingPlugin")
+});
diff --git a/package.json b/package.json
index 7d28740e3..9f50a6c02 100644
--- a/package.json
+++ b/package.json
@@ -9,6 +9,7 @@
     "ajv": "^5.1.5",
     "ajv-keywords": "^2.0.0",
     "async": "^2.1.2",
+    "chrome-trace-event": "^0.1.1",
     "enhanced-resolve": "^4.0.0-beta.2",
     "eslint-scope": "^3.7.1",
     "loader-runner": "^2.3.0",
diff --git a/test/ProfilingPlugin.unittest.js b/test/ProfilingPlugin.unittest.js
new file mode 100644
index 000000000..9d7746957
--- /dev/null
+++ b/test/ProfilingPlugin.unittest.js
@@ -0,0 +1,62 @@
+"use strict";
+
+require("should");
+const ProfilingPlugin = require("../lib/debug/ProfilingPlugin");
+
+describe("Profiling Plugin", () => {
+	it("should persist the passed outpath", () => {
+		const plugin = new ProfilingPlugin({
+			outPath: "invest_in_doge_coin"
+		});
+		plugin.outPath.should.equal("invest_in_doge_coin");
+	});
+
+	it("should handle no options", () => {
+		const plugin = new ProfilingPlugin();
+		plugin.outPath.should.equal("events.json");
+	});
+
+	it("should handle when unable to require the inspector", (done) => {
+		const profiler = new ProfilingPlugin.Profiler();
+
+		profiler.startProfiling().then(() => {
+			done();
+		}).catch(e => {
+			done(e);
+		});
+	});
+
+	it("should handle when unable to start a profiling session", (done) => {
+		const profiler = new ProfilingPlugin.Profiler({
+			Session() {
+				throw new Error("Sean Larkin was here.");
+			}
+		});
+
+		profiler.startProfiling().then(() => {
+			done();
+		}).catch(e => {
+			done(e);
+		});
+	});
+
+	it("handles sending a profiling message when no session", (done) => {
+		const profiler = new ProfilingPlugin.Profiler();
+
+		profiler.sendCommand("randy", "is a puppers").then(() => {
+			done();
+		}).catch(e => {
+			done(e);
+		});
+	});
+
+	it("handles destroying when no session", (done) => {
+		const profiler = new ProfilingPlugin.Profiler();
+
+		profiler.destroy().then(() => {
+			done();
+		}).catch(e => {
+			done(e);
+		});
+	});
+});
diff --git a/test/configCases/plugins/profiling-plugin/index.js b/test/configCases/plugins/profiling-plugin/index.js
new file mode 100644
index 000000000..a3e4de9bd
--- /dev/null
+++ b/test/configCases/plugins/profiling-plugin/index.js
@@ -0,0 +1,16 @@
+it("should generate a events.json file", () => {
+    var fs = require("fs"),
+        path = require("path"),
+        os = require("os");
+    fs.existsSync(path.join(os.tmpdir(), "events.json")).should.be.true();
+});
+
+it("should have proper setup record inside of the json stream", () => {
+    var fs = require("fs"),
+        path = require("path"),
+        os = require("os");
+
+    // convert json stream to valid
+    var source = JSON.parse(fs.readFileSync(path.join(os.tmpdir(), "events.json"), "utf-8").toString() + "{}]");
+    source[0].id.should.eql(1);
+});
\ No newline at end of file
diff --git a/test/configCases/plugins/profiling-plugin/webpack.config.js b/test/configCases/plugins/profiling-plugin/webpack.config.js
new file mode 100644
index 000000000..2c6349ac6
--- /dev/null
+++ b/test/configCases/plugins/profiling-plugin/webpack.config.js
@@ -0,0 +1,16 @@
+var rootPath = "../../../../";
+var webpack = require(rootPath);
+var path = require("path");
+var os = require("os");
+
+module.exports = {
+    plugins: [
+        new webpack.debug.ProfilingPlugin({
+            outPath: path.join(os.tmpdir(), "events.json")
+        })
+    ],
+    node: {
+        __dirname: false,
+        __filename: false
+    }
+};
diff --git a/yarn.lock b/yarn.lock
index f0f6d03b0..f1f59c60c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -539,6 +539,10 @@ chownr@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/chownr/-/chownr-1.0.1.tgz#e2a75042a9551908bebd25b8523d5f9769d79181"
 
+chrome-trace-event@^0.1.1:
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/chrome-trace-event/-/chrome-trace-event-0.1.1.tgz#651f4d115902160b0b33aca136574b17d1519c98"
+
 cipher-base@^1.0.0, cipher-base@^1.0.1, cipher-base@^1.0.3:
   version "1.0.4"
   resolved "https://registry.yarnpkg.com/cipher-base/-/cipher-base-1.0.4.tgz#8760e4ecc272f4c363532f926d874aae2c1397de"