next
Version:
The React Framework
201 lines (200 loc) • 9.06 kB
JavaScript
import fs from 'fs';
import nodePath from 'path';
import { bold, cyan } from '../lib/picocolors';
import * as Log from './output/log';
import { getBindingsSync } from './swc';
const RETRY_DELAY_MS = 10;
const MAX_RETRY_MS = 1000;
/**
* Reads dev server info from a lockfile.
* Returns undefined if the file doesn't exist or can't be parsed.
*
* Uses Node's fs.readFileSync which works on both Unix (with advisory flock)
* and Windows (with FILE_SHARE_READ flag set by the lock holder).
*/ export function readLockfileContent(lockfilePath) {
try {
return fs.readFileSync(lockfilePath, 'utf-8');
} catch {
return undefined;
}
}
/**
* Parses dev server info from lockfile content.
*/ export function parseDevServerInfo(content) {
try {
return JSON.parse(content);
} catch {
return undefined;
}
}
/**
* A cross-platform on-disk best-effort advisory exclusive lockfile
* implementation.
*
* On Windows, this opens a file in write mode with the `FILE_SHARE_WRITE` flag
* unset, so it still allows reading the lockfile. This avoids breaking tools
* that read the contents of `.next`.
*
* On POSIX platforms, this uses `flock()` via `std::fs::File::try_lock`:
* https://doc.rust-lang.org/std/fs/struct.File.html#method.try_lock
*
* On WASM, a dummy implementation is used which always "succeeds" in acquiring
* the lock.
*
* This provides a more idiomatic wrapper around the lockfile APIs exposed on
* the native bindings object.
*
* If this lock is not explicitly closed with `unlock`, we will:
* - If `unlockOnExit` is set (the default), it will make a best-effort attempt
* to unlock the lockfile using `process.on('exit', ...)`. This is preferrable
* on Windows where it may take some time after process exit for the operating
* system to clean up locks that are not explicitly released by the process.
* - If we fail to ever release the lockfile, the operating system will clean up
* the lock and file descriptor upon process exit.
*/ export class Lockfile {
constructor(bindings, nativeLockfile){
this.bindings = bindings;
this.nativeLockfile = nativeLockfile;
}
/**
* Attempts to create or acquire an exclusive lockfile on disk. Lockfiles are
* best-effort, depending on the platform.
*
* - If we fail to acquire the lock, we return `undefined`.
* - If we're on wasm, this always returns a dummy `Lockfile` object.
*
* @param path - Path to the lock file
* @param unlockOnExit - Whether to unlock the file on process exit
* @param content - Optional content to write to the lockfile (e.g., JSON with server info)
*/ static tryAcquire(path, unlockOnExit = true, content) {
const bindings = getBindingsSync();
if (bindings.isWasm) {
Log.info(`Skipping creating a lockfile at ${cyan(path)} because we're using WASM bindings`);
return new Lockfile(bindings, undefined);
} else {
let nativeLockfile;
try {
nativeLockfile = bindings.lockfileTryAcquireSync(path, content);
} catch (e) {
// this happens if there's an IO error (e.g. `ENOENT`), which is
// different than if we just didn't acquire the lock
throw Object.defineProperty(new Error('An IO error occurred while attempting to create and acquire the lockfile', {
cause: e
}), "__NEXT_ERROR_CODE", {
value: "E859",
enumerable: false,
configurable: true
});
}
if (nativeLockfile != null) {
const jsLockfile = new Lockfile(bindings, nativeLockfile);
if (unlockOnExit) {
const exitListener = ()=>{
// Best-Effort: If we don't do this, the operating system will
// release the lock for us. This gives an opportunity to delete the
// unlocked lockfile (which is not otherwise deleted on POSIX).
//
// This must be synchronous because `process.on('exit', ...)` is
// synchronous.
jsLockfile.unlockSync();
};
process.on('exit', exitListener);
jsLockfile.listener = exitListener;
}
return jsLockfile;
} else {
return undefined;
}
}
}
/**
* Attempts to create or acquire a lockfile using `Lockfile.tryAcquire`. If
* that returns `undefined`, indicating that another process or caller has the
* lockfile, then this will output an error message and exit the process with
* a non-zero exit code.
*
* This will retry a small number of times. This can be useful when running
* processes in a loop, e.g. if cleanup isn't fully synchronous due to child
* parent/processes.
*
* @param path - Path to the lock file
* @param processName - Name of the process for error messages (e.g., 'next dev')
* @param unlockOnExit - Whether to unlock the file on process exit
* @param content - Optional content to write to the lockfile (e.g., JSON with server info)
* @param projectDir - Optional project directory for enhanced error messages
* @param relativeDistDir - Optional relative dist directory path (e.g., '.next/dev')
*/ static async acquireWithRetriesOrExit(path, processName, unlockOnExit = true, content, projectDir, relativeDistDir) {
const startMs = Date.now();
let lockfile;
while(Date.now() - startMs < MAX_RETRY_MS){
lockfile = Lockfile.tryAcquire(path, unlockOnExit, content);
if (lockfile !== undefined) break;
await new Promise((resolve)=>setTimeout(resolve, RETRY_DELAY_MS));
}
if (lockfile === undefined) {
const isDev = processName === 'next dev';
if (isDev) {
// For dev server, try to read server info from the lockfile itself
const lockfileContent = readLockfileContent(path);
const serverInfo = lockfileContent ? parseDevServerInfo(lockfileContent) : undefined;
if (serverInfo) {
Log.error(`Another ${cyan(processName)} server is already running.`);
console.error();
console.error(`- Local: ${cyan(serverInfo.appUrl)}`);
console.error(`- PID: ${serverInfo.pid}`);
if (projectDir) {
console.error(`- Dir: ${projectDir}`);
}
if (relativeDistDir) {
console.error(`- Log: ${nodePath.join(relativeDistDir, 'logs', 'next-development.log')}`);
}
console.error();
// Use platform-appropriate kill command
const killCommand = process.platform === 'win32' ? `taskkill /PID ${serverInfo.pid} /F` : `kill ${serverInfo.pid}`;
console.error(`Run ${cyan(killCommand)} to stop it.`);
} else {
// Fallback when we can't read server info from the lockfile
Log.error(`Another ${cyan(processName)} server is already running in this directory.`);
console.error(`Stop the other server before starting a new one.`);
}
} else {
// For build, show that a build is in progress
Log.error(`Another ${cyan(processName)} process is already running.`);
console.error();
console.error(` This could be:`);
console.error(` - A ${cyan('next build')} still in progress`);
console.error(` - A previous build that didn't exit cleanly`);
console.error();
Log.info(`${bold('Suggestion:')} Wait for the build to complete.`);
}
process.exit(1);
}
return lockfile;
}
/**
* Releases the lockfile and closes the file descriptor.
*
* If this is not called, the lock will be released by the operating system
* when the file handle is closed during process exit.
*/ async unlock() {
const { nativeLockfile, listener } = this;
if (nativeLockfile !== undefined) {
await this.bindings.lockfileUnlock(nativeLockfile);
}
if (listener !== undefined) {
process.off('exit', listener);
}
}
/**
* A blocking version of `unlock`.
*/ unlockSync() {
const { nativeLockfile, listener } = this;
if (nativeLockfile !== undefined) {
this.bindings.lockfileUnlockSync(nativeLockfile);
}
if (listener !== undefined) {
process.off('exit', listener);
}
}
}
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