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Split child and parent wrappers

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I think having them combined and relying on if statements was getting
confusing especially if we want to add additional messages with
different payloads (which will soon be the case).
This commit is contained in:
Asher 2020-11-18 11:43:25 -06:00
parent 2a3608df53
commit d55e06936b
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GPG Key ID: D63C1EF81242354A
3 changed files with 146 additions and 103 deletions
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13
src/node/entry.ts
View File

@ -19,7 +19,7 @@ import { coderCloudBind } from "./coder-cloud"
import { commit, version } from "./constants"
import { register } from "./routes"
import { humanPath, isFile, open } from "./util"
import { ipcMain, WrapperProcess } from "./wrapper"
import { isChild, wrapper } from "./wrapper"
export const runVsCodeCli = (args: DefaultedArgs): void => {
logger.debug("forking vs code cli...")
@ -137,7 +137,7 @@ const main = async (args: DefaultedArgs): Promise<void> => {
logger.info(" - Connected to cloud agent")
} catch (err) {
logger.error(err.message)
ipcMain.exit(1)
wrapper.exit(1)
}
}
@ -161,9 +161,9 @@ async function entry(): Promise<void> {
// There's no need to check flags like --help or to spawn in an existing
// instance for the child process because these would have already happened in
// the parent and the child wouldn't have been spawned.
if (ipcMain.isChild) {
await ipcMain.handshake()
ipcMain.preventExit()
if (isChild(wrapper)) {
await wrapper.handshake()
wrapper.preventExit()
return main(args)
}
@ -201,11 +201,10 @@ async function entry(): Promise<void> {
return openInExistingInstance(args, socketPath)
}
const wrapper = new WrapperProcess(require("../../package.json").version)
return wrapper.start()
}
entry().catch((error) => {
logger.error(error.message)
ipcMain.exit(error)
wrapper.exit(error)
})

4
src/node/vscode.ts
View File

@ -8,7 +8,7 @@ import { rootPath } from "./constants"
import { settings } from "./settings"
import { SocketProxyProvider } from "./socket"
import { isFile } from "./util"
import { ipcMain } from "./wrapper"
import { wrapper } from "./wrapper"
export class VscodeProvider {
public readonly serverRootPath: string
@ -20,7 +20,7 @@ export class VscodeProvider {
public constructor() {
this.vsRootPath = path.resolve(rootPath, "lib/vscode")
this.serverRootPath = path.join(this.vsRootPath, "out/vs/server")
ipcMain.onDispose(() => this.dispose())
wrapper.onDispose(() => this.dispose())
}
public async dispose(): Promise<void> {

232
src/node/wrapper.ts
View File

@ -1,4 +1,4 @@
import { field, logger } from "@coder/logger"
import { Logger, field, logger } from "@coder/logger"
import * as cp from "child_process"
import * as path from "path"
import * as rfs from "rotating-file-stream"
@ -14,9 +14,9 @@ interface RelaunchMessage {
version: string
}
export type Message = RelaunchMessage | HandshakeMessage
type Message = RelaunchMessage | HandshakeMessage
export class ProcessError extends Error {
class ProcessError extends Error {
public constructor(message: string, public readonly code: number | undefined) {
super(message)
this.name = this.constructor.name
@ -25,16 +25,26 @@ export class ProcessError extends Error {
}
/**
* Allows the wrapper and inner processes to communicate.
* Wrapper around a process that tries to gracefully exit when a process exits
* and provides a way to prevent `process.exit`.
*/
export class IpcMain {
private readonly _onMessage = new Emitter<Message>()
public readonly onMessage = this._onMessage.event
private readonly _onDispose = new Emitter<NodeJS.Signals | undefined>()
public readonly onDispose = this._onDispose.event
public readonly processExit: (code?: number) => never = process.exit
abstract class Process {
/**
* Emit this to trigger a graceful exit.
*/
protected readonly _onDispose = new Emitter<NodeJS.Signals | undefined>()
public constructor(private readonly parentPid?: number) {
/**
* Emitted when the process is about to be disposed.
*/
public readonly onDispose = this._onDispose.event
/**
* Uniquely named logger for the process.
*/
public abstract logger: Logger
public constructor() {
process.on("SIGINT", () => this._onDispose.emit("SIGINT"))
process.on("SIGTERM", () => this._onDispose.emit("SIGTERM"))
process.on("exit", () => this._onDispose.emit(undefined))
@ -43,42 +53,27 @@ export class IpcMain {
// Remove listeners to avoid possibly triggering disposal again.
process.removeAllListeners()
// Try waiting for other handlers run first then exit.
logger.debug(`${parentPid ? "inner process" : "wrapper"} ${process.pid} disposing`, field("code", signal))
// Try waiting for other handlers to run first then exit.
this.logger.debug("disposing", field("code", signal))
wait.then(() => this.exit(0))
setTimeout(() => this.exit(0), 5000)
})
// Kill the inner process if the parent dies. This is for the case where the
// parent process is forcefully terminated and cannot clean up.
if (parentPid) {
setInterval(() => {
try {
// process.kill throws an exception if the process doesn't exist.
process.kill(parentPid, 0)
} catch (_) {
// Consider this an error since it should have been able to clean up
// the child process unless it was forcefully killed.
logger.error(`parent process ${parentPid} died`)
this._onDispose.emit(undefined)
}
}, 5000)
}
}
/**
* Ensure we control when the process exits.
* Ensure control over when the process exits.
*/
public preventExit(): void {
process.exit = function (code?: number) {
logger.warn(`process.exit() was prevented: ${code || "unknown code"}.`)
} as (code?: number) => never
;(process.exit as any) = (code?: number) => {
this.logger.warn(`process.exit() was prevented: ${code || "unknown code"}.`)
}
}
public get isChild(): boolean {
return typeof this.parentPid !== "undefined"
}
private readonly processExit: (code?: number) => never = process.exit
/**
* Will always exit even if normal exit is being prevented.
*/
public exit(error?: number | ProcessError): never {
if (error && typeof error !== "number") {
this.processExit(typeof error.code === "number" ? error.code : 1)
@ -86,47 +81,61 @@ export class IpcMain {
this.processExit(error)
}
}
}
public handshake(child?: cp.ChildProcess): Promise<void> {
return new Promise((resolve, reject) => {
const target = child || process
/**
* Child process that will clean up after itself if the parent goes away and can
* perform a handshake with the parent and ask it to relaunch.
*/
class ChildProcess extends Process {
public logger = logger.named(`child:${process.pid}`)
public constructor(private readonly parentPid: number) {
super()
// Kill the inner process if the parent dies. This is for the case where the
// parent process is forcefully terminated and cannot clean up.
setInterval(() => {
try {
// process.kill throws an exception if the process doesn't exist.
process.kill(this.parentPid, 0)
} catch (_) {
// Consider this an error since it should have been able to clean up
// the child process unless it was forcefully killed.
this.logger.error(`parent process ${parentPid} died`)
this._onDispose.emit(undefined)
}
}, 5000)
}
/**
* Initiate the handshake and wait for a response from the parent.
*/
public handshake(): Promise<void> {
return new Promise((resolve) => {
const onMessage = (message: Message): void => {
logger.debug(
`${child ? "wrapper" : "inner process"} ${process.pid} received message from ${
child ? child.pid : this.parentPid
}`,
field("message", message),
)
logger.debug(`received message from ${this.parentPid}`, field("message", message))
if (message.type === "handshake") {
target.removeListener("message", onMessage)
target.on("message", (msg) => this._onMessage.emit(msg))
// The wrapper responds once the inner process starts the handshake.
if (child) {
if (!target.send) {
throw new Error("child not spawned with IPC")
}
target.send({ type: "handshake" })
}
process.removeListener("message", onMessage)
resolve()
}
}
target.on("message", onMessage)
if (child) {
child.once("error", reject)
child.once("exit", (code) => {
reject(new ProcessError(`Unexpected exit with code ${code}`, code !== null ? code : undefined))
})
} else {
// The inner process initiates the handshake.
this.send({ type: "handshake" })
}
// Initiate the handshake and wait for the reply.
process.on("message", onMessage)
this.send({ type: "handshake" })
})
}
/**
* Notify the parent process that it should relaunch the child.
*/
public relaunch(version: string): void {
this.send({ type: "relaunch", version })
}
/**
* Send a message to the parent.
*/
private send(message: Message): void {
if (!process.send) {
throw new Error("not spawned with IPC")
@ -135,29 +144,30 @@ export class IpcMain {
}
}
/**
* Channel for communication between the child and parent processes.
*/
export const ipcMain = new IpcMain(
typeof process.env.CODE_SERVER_PARENT_PID !== "undefined" ? parseInt(process.env.CODE_SERVER_PARENT_PID) : undefined,
)
export interface WrapperOptions {
maxMemory?: number
nodeOptions?: string
}
/**
* Provides a way to wrap a process for the purpose of updating the running
* instance.
* Parent process wrapper that spawns the child process and performs a handshake
* with it. Will relaunch the child if it receives a SIGUSR1 or is asked to by
* the child. If the child otherwise exits the parent will also exit.
*/
export class WrapperProcess {
private process?: cp.ChildProcess
export class ParentProcess extends Process {
public logger = logger.named(`parent:${process.pid}`)
private child?: cp.ChildProcess
private started?: Promise<void>
private readonly logStdoutStream: rfs.RotatingFileStream
private readonly logStderrStream: rfs.RotatingFileStream
protected readonly _onChildMessage = new Emitter<Message>()
protected readonly onChildMessage = this._onChildMessage.event
public constructor(private currentVersion: string, private readonly options?: WrapperOptions) {
super()
const opts = {
size: "10M",
maxFiles: 10,
@ -165,19 +175,19 @@ export class WrapperProcess {
this.logStdoutStream = rfs.createStream(path.join(paths.data, "coder-logs", "code-server-stdout.log"), opts)
this.logStderrStream = rfs.createStream(path.join(paths.data, "coder-logs", "code-server-stderr.log"), opts)
ipcMain.onDispose(() => {
this.onDispose(() => {
this.disposeChild()
})
ipcMain.onMessage((message) => {
this.onChildMessage((message) => {
switch (message.type) {
case "relaunch":
logger.info(`Relaunching: ${this.currentVersion} -> ${message.version}`)
this.logger.info(`Relaunching: ${this.currentVersion} -> ${message.version}`)
this.currentVersion = message.version
this.relaunch()
break
default:
logger.error(`Unrecognized message ${message}`)
this.logger.error(`Unrecognized message ${message}`)
break
}
})
@ -185,9 +195,9 @@ export class WrapperProcess {
private disposeChild(): void {
this.started = undefined
if (this.process) {
this.process.removeAllListeners()
this.process.kill()
if (this.child) {
this.child.removeAllListeners()
this.child.kill()
}
}
@ -196,16 +206,16 @@ export class WrapperProcess {
try {
await this.start()
} catch (error) {
logger.error(error.message)
ipcMain.exit(typeof error.code === "number" ? error.code : 1)
this.logger.error(error.message)
this.exit(typeof error.code === "number" ? error.code : 1)
}
}
public start(): Promise<void> {
// If we have a process then we've already bound this.
if (!this.process) {
if (!this.child) {
process.on("SIGUSR1", async () => {
logger.info("Received SIGUSR1; hotswapping")
this.logger.info("Received SIGUSR1; hotswapping")
this.relaunch()
})
}
@ -217,7 +227,7 @@ export class WrapperProcess {
private async _start(): Promise<void> {
const child = this.spawn()
this.process = child
this.child = child
// Log both to stdout and to the log directory.
if (child.stdout) {
@ -229,13 +239,13 @@ export class WrapperProcess {
child.stderr.pipe(process.stderr)
}
logger.debug(`spawned inner process ${child.pid}`)
this.logger.debug(`spawned inner process ${child.pid}`)
await ipcMain.handshake(child)
await this.handshake(child)
child.once("exit", (code) => {
logger.debug(`inner process ${child.pid} exited unexpectedly`)
ipcMain.exit(code || 0)
this.logger.debug(`inner process ${child.pid} exited unexpectedly`)
this.exit(code || 0)
})
}
@ -256,18 +266,52 @@ export class WrapperProcess {
stdio: ["ipc"],
})
}
/**
* Wait for a handshake from the child then reply.
*/
private handshake(child: cp.ChildProcess): Promise<void> {
return new Promise((resolve, reject) => {
const onMessage = (message: Message): void => {
logger.debug(`received message from ${child.pid}`, field("message", message))
if (message.type === "handshake") {
child.removeListener("message", onMessage)
child.on("message", (msg) => this._onChildMessage.emit(msg))
child.send({ type: "handshake" })
resolve()
}
}
child.on("message", onMessage)
child.once("error", reject)
child.once("exit", (code) => {
reject(new ProcessError(`Unexpected exit with code ${code}`, code !== null ? code : undefined))
})
})
}
}
/**
* Process wrapper.
*/
export const wrapper =
typeof process.env.CODE_SERVER_PARENT_PID !== "undefined"
? new ChildProcess(parseInt(process.env.CODE_SERVER_PARENT_PID))
: new ParentProcess(require("../../package.json").version)
export function isChild(proc: ChildProcess | ParentProcess): proc is ChildProcess {
return proc instanceof ChildProcess
}
// It's possible that the pipe has closed (for example if you run code-server
// --version | head -1). Assume that means we're done.
if (!process.stdout.isTTY) {
process.stdout.on("error", () => ipcMain.exit())
process.stdout.on("error", () => wrapper.exit())
}
// Don't let uncaught exceptions crash the process.
process.on("uncaughtException", (error) => {
logger.error(`Uncaught exception: ${error.message}`)
wrapper.logger.error(`Uncaught exception: ${error.message}`)
if (typeof error.stack !== "undefined") {
logger.error(error.stack)
wrapper.logger.error(error.stack)
}
})