watch: add initial implementation for node --watch
#44366
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,132 @@ | ||
| 'use strict'; | ||
| const { | ||
| ArrayPrototypeFilter, | ||
| ArrayPrototypeForEach, | ||
| ArrayPrototypeJoin, | ||
| ArrayPrototypeMap, | ||
| ArrayPrototypePushApply, | ||
| ArrayPrototypeSlice, | ||
| } = primordials; | ||
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| const { | ||
| prepareMainThreadExecution, | ||
| markBootstrapComplete | ||
| } = require('internal/process/pre_execution'); | ||
| const { triggerUncaughtException } = internalBinding('errors'); | ||
| const { getOptionValue } = require('internal/options'); | ||
| const { emitExperimentalWarning } = require('internal/util'); | ||
| const { FilesWatcher } = require('internal/watch_mode/files_watcher'); | ||
| const { green, blue, red, white, clear } = require('internal/util/colors'); | ||
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| const { spawn } = require('child_process'); | ||
| const { inspect } = require('util'); | ||
| const { setTimeout, clearTimeout } = require('timers'); | ||
| const { resolve } = require('path'); | ||
| const { once, on } = require('events'); | ||
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| prepareMainThreadExecution(false, false); | ||
| markBootstrapComplete(); | ||
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| // TODO(MoLow): Make kill signal configurable | ||
| const kKillSignal = 'SIGTERM'; | ||
| const kShouldFilterModules = getOptionValue('--watch-path').length === 0; | ||
| const kWatchedPaths = ArrayPrototypeMap(getOptionValue('--watch-path'), (path) => resolve(path)); | ||
| const kCommand = ArrayPrototypeSlice(process.argv, 1); | ||
| const kCommandStr = inspect(ArrayPrototypeJoin(kCommand, ' ')); | ||
| const args = ArrayPrototypeFilter(process.execArgv, (arg, i, arr) => | ||
| arg !== '--watch-path' && arr[i - 1] !== '--watch-path' && arg !== '--watch'); | ||
| ArrayPrototypePushApply(args, kCommand); | ||
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| const watcher = new FilesWatcher({ throttle: 500, mode: kShouldFilterModules ? 'filter' : 'all' }); | ||
| ArrayPrototypeForEach(kWatchedPaths, (p) => watcher.watchPath(p)); | ||
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| let graceTimer; | ||
| let child; | ||
| let exited; | ||
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| function start() { | ||
| exited = false; | ||
| const stdio = kShouldFilterModules ? ['inherit', 'inherit', 'inherit', 'ipc'] : undefined; | ||
| child = spawn(process.execPath, args, { stdio, env: { ...process.env, WATCH_REPORT_DEPENDENCIES: '1' } }); | ||
| watcher.watchChildProcessModules(child); | ||
| child.once('exit', (code) => { | ||
| exited = true; | ||
| if (code === 0) { | ||
| process.stdout.write(`${blue}Completed running ${kCommandStr}${white}\n`); | ||
| } else { | ||
| process.stdout.write(`${red}Failed running ${kCommandStr}${white}\n`); | ||
| } | ||
| }); | ||
| } | ||
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| async function killAndWait(signal = kKillSignal, force = false) { | ||
| child?.removeAllListeners(); | ||
| if (!child) { | ||
| return; | ||
| } | ||
| if ((child.killed || exited) && !force) { | ||
| return; | ||
| } | ||
| const onExit = once(child, 'exit'); | ||
| child.kill(signal); | ||
| const { 0: exitCode } = await onExit; | ||
| return exitCode; | ||
| } | ||
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| function reportGracefulTermination() { | ||
| // Log if process takes more than 500ms to stop. | ||
| let reported = false; | ||
| clearTimeout(graceTimer); | ||
| graceTimer = setTimeout(() => { | ||
| reported = true; | ||
| process.stdout.write(`${blue}Waiting for graceful termination...${white}\n`); | ||
| }, 500).unref(); | ||
| return () => { | ||
| clearTimeout(graceTimer); | ||
| if (reported) { | ||
| process.stdout.write(`${clear}${green}Gracefully restarted ${kCommandStr}${white}\n`); | ||
| } | ||
| }; | ||
| } | ||
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| async function stop() { | ||
| watcher.clearFileFilters(); | ||
| const clearGraceReport = reportGracefulTermination(); | ||
| await killAndWait(); | ||
| clearGraceReport(); | ||
| } | ||
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| async function restart() { | ||
| process.stdout.write(`${clear}${green}Restarting ${kCommandStr}${white}\n`); | ||
|
There was a problem hiding this comment. This "clear" should be at least configurable, as the |
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| await stop(); | ||
| start(); | ||
| } | ||
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| (async () => { | ||
| emitExperimentalWarning('Watch mode'); | ||
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| try { | ||
| start(); | ||
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| // eslint-disable-next-line no-unused-vars | ||
| for await (const _ of on(watcher, 'changed')) { | ||
| await restart(); | ||
| } | ||
| } catch (error) { | ||
| triggerUncaughtException(error, true /* fromPromise */); | ||
| } | ||
| })(); | ||
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| // Exiting gracefully to avoid stdout/stderr getting written after | ||
| // parent process is killed. | ||
| // this is fairly safe since user code cannot run in this process | ||
| function signalHandler(signal) { | ||
| return async () => { | ||
| watcher.clear(); | ||
| const exitCode = await killAndWait(signal, true); | ||
| process.exit(exitCode ?? 0); | ||
| }; | ||
| } | ||
| process.on('SIGTERM', signalHandler('SIGTERM')); | ||
| process.on('SIGINT', signalHandler('SIGINT')); | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,23 @@ | ||
| 'use strict'; | ||
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| module.exports = { | ||
| blue: '', | ||
| green: '', | ||
| white: '', | ||
| red: '', | ||
| clear: '', | ||
| hasColors: false, | ||
| refresh() { | ||
| if (process.stderr.isTTY) { | ||
| const hasColors = process.stderr.hasColors(); | ||
| module.exports.blue = hasColors ? '\u001b[34m' : ''; | ||
| module.exports.green = hasColors ? '\u001b[32m' : ''; | ||
| module.exports.white = hasColors ? '\u001b[39m' : ''; | ||
| module.exports.red = hasColors ? '\u001b[31m' : ''; | ||
| module.exports.clear = hasColors ? '\u001bc' : ''; | ||
| module.exports.hasColors = hasColors; | ||
| } | ||
| } | ||
| }; | ||
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| module.exports.refresh(); |
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What part of this is disabled or partially functional on Linux?
fs.watch()has caveats but certainly doesn't advertise as limited to Windows and macOS.Is there an open issue for making this supported on Linux?