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process.js
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process.js
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/**
* Copyright (c) 2017-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @flow
* @format
*/
//
// __ __ __ __ ___ __ __ __
// |__) |__) / \ / ` |__ /__` /__` | /__`
// | | \ \__/ \__, |___ .__/ .__/ .\__/ .__/
//
// This module contains utilities for spawning processes in Nuclide. In general:
//
// - They accept similar arguments.
// - They return an observable.
// - The process is spawned if/when you subscribe to the observable.
// - If you unsubscribe before the observable completes, the process is killed.
// - The observable errors if the process completes with a non-zero exit code (by default; this can
// be changed) or if the process can't be spawned.
//
// The most important functions in this module are `runCommand()`--for running a quick command and
// getting its output--and `observeProcess()`--for streaming output from a process. They'll handle
// the majority of use cases.
//
// ## Why observables?
//
// Unlike Promises, observables have a standardized, composable cancellation mechanism _today_.
// Moreover, observables integrate nicely with Atom's callback + IDisposable formula for cancelable,
// async APIs. Along with React, [RxJS] is one of the core libraries utilized by Nuclide.
//
// ## Why errors?
//
// In the past, we had some process APIs that used errors and some that used return values.
// Consistency has obvious benefits; standardizing on errors makes sense because:
//
// - The error-throwing APIs were the most used, by a large margin.
// - Unhandled errors can be caught and logged at the top level.
// - Observables have a separate channel for errors which allows for cool, error-aware operators
// like `retry()` and caching.
// - Errors in observables are stream-ending. This means you won't continue to do work in a chain of
// operators accidentally.
//
// [RxJS]: http://reactivex.io/rxjs/
import child_process from 'child_process';
import idx from 'idx';
import {getLogger} from 'log4js';
import invariant from 'assert';
import {Observable} from 'rxjs';
import util from 'util';
import UniversalDisposable from './UniversalDisposable';
import nuclideUri from './nuclideUri';
import performanceNow from './performanceNow';
import {MultiMap} from './collection';
import {observableFromSubscribeFunction} from './event';
import {observeStream} from './stream';
import {splitStream, takeWhileInclusive} from './observable';
import {shellQuote} from './string';
export const LOG_CATEGORY = 'nuclide-commons/process';
const NUCLIDE_DO_NOT_LOG = global.NUCLIDE_DO_NOT_LOG;
const logger = getLogger(LOG_CATEGORY);
/**
* Run a command, accumulate the output. Errors are surfaced as stream errors and unsubscribing will
* kill the process. In addition to the options accepted by Node's [`child_process.spawn()`][1]
* function, `runCommand()` also accepts the following:
*
* - `input` {string | Observable<string>} Text to write to the new process's stdin.
* - `killTreeWhenDone` {boolean} `false` by default. If you pass `true`, unsubscribing from the
* observable will kill not only this process but also its descendants.
* - `isExitError` {function} Determines whether a ProcessExitError should be raised based on the
* exit message. By default, this is a function that returns `true` if the exit code is non-zero.
* - `maxBuffer` {number} The maximum amount of stdout and stderror to accumulate. If the process
* produces more of either, a MaxBufferExceededError will be emitted.
* - `timeout` {number} The number of milliseconds to wait before killing the process and emitting
* an error. This is mostly provided for backwards compatibility, as you can get the same result
* by using the `.timeout()` operator on the returned observable.
*
* The observable returned by this function can error with any of the following:
*
* - `ProcessSystemError` Wrap [Node System Errors][2] (which are just augmented `Error` objects)
* and include things like `ENOENT`. These contain all of the properties of node system errors
* as well as a reference to the process.
* - `ProcessExitError` Indicate that the process has ended cleanly, but with an unsuccessful exit
* code. Whether a `ProcessExitError` is thrown is determined by the `isExitError` option. This
* error includes the exit code as well as accumulated stdout and stderr. See its definition for
* more information.
* - `MaxBufferExceededError` Thrown if either the stdout or stderr exceeds the value specified by
* the `maxBuffer` option.
* - `ProcessTimeoutError` Thrown if the process doesn't complete within the time specified by the
* `timeout` option.
*
* Example:
*
* ```js
* const subscription = runCommand('ps', ['-e', '-o', 'pid,comm'])
* .map(stdout => {
* return stdout.split('\n')
* .slice(1)
* .map(line => {
* const words = line.trim().split(' ');
* return {
* pid: words[0],
* command: words.slice(1).join(' '),
* };
* })
* .sort((p1, p2) => p2.pid - p1.pid);
* })
* .subscribe(processes => {
* console.log(`The process with the highest pid is ${processes[0].command}`);
* });
* ```
*
* [1]: https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options
* [2]: https://nodejs.org/api/errors.html#errors_class_system_error
*/
export function runCommand(
command: string,
args?: Array<string> = [],
options?: ObserveProcessOptions = {},
rest: void,
): Observable<string> {
return runCommandDetailed(command, args, options).map(event => event.stdout);
}
/**
* Returns an observable that spawns a process and emits events on stdout, stderr and exit. Output
* is buffered by line. Unsubscribing before the observable completes will kill the process. This
* function accepts the same options as `runCommand()`, and throws the same errors.
*
* Besides emitting multiple events, another difference with `runCommand()` is the ProcessExitErrors
* thrown by `observeProcess()`. Whereas ProcessExitErrors thrown by `runCommand()` contain the
* entirety of stdout and stderr, those thrown by `observeProcess()` contain a truncated amount of
* stderr and no stdout. This is because `observeProcess()` is usually used with long-running
* processes that may continue to produce output for a long while. The abbreviated stderr is
* included to help with debugging.
*
* Example:
*
* ```js
* const filesToTail: Observable<NuclideUri> = f();
* const subscription = filesToTail
* // `switchMap()` means only one file will be tailed at a time.
* .switchMap(path => observeProcess('tail', ['-f', path]))
* .filter(event => event.kind === 'stdout')
* .map(event => event.data)
* .subscribe(line => {
* console.log(line);
* });
* ```
*/
export function observeProcess(
command: string,
args?: Array<string>,
options?: ObserveProcessOptions,
): Observable<ProcessMessage> {
return spawn(command, args, options).flatMap(proc =>
getOutputStream(proc, options),
);
}
export type DetailedProcessResult = {
stdout: string,
stderr: string,
exitCode: ?number,
};
/**
* Identical to `runCommand()`, but instead of only emitting the accumulated stdout, the returned
* observable emits an object containing the accumulated stdout, the accumulated stderr, and the
* exit code.
*
* In general, you should prefer `runCommand()`, however, this function is useful for when stderr is
* needed even if the process exits successfully.
*/
export function runCommandDetailed(
command: string,
args?: Array<string> = [],
options?: ObserveProcessOptions = {},
rest: void,
): Observable<DetailedProcessResult> {
const maxBuffer = idx(options, _ => _.maxBuffer) || DEFAULT_MAX_BUFFER;
return observeProcess(command, args, {...options, maxBuffer})
.catch(error => {
// Catch ProcessExitErrors so that we can add stdout to them.
if (error instanceof ProcessExitError) {
return Observable.of({kind: 'process-exit-error', error});
}
throw error;
})
.reduce(
(acc, event) => {
switch (event.kind) {
case 'stdout':
return {...acc, stdout: acc.stdout + event.data};
case 'stderr':
return {...acc, stderr: acc.stderr + event.data};
case 'exit':
return {...acc, exitCode: event.exitCode};
case 'process-exit-error':
const {error} = event;
throw new ProcessExitError(
error.exitCode,
error.signal,
error.process,
acc.stderr,
acc.stdout,
);
default:
(event.kind: empty);
throw new Error(`Invalid event kind: ${event.kind}`);
}
},
{stdout: '', stderr: '', exitCode: null},
);
}
/**
* Identical to `observeProcess()`, but doesn't buffer by line.
*/
export function observeProcessRaw(
command: string,
args?: Array<string>,
options?: ObserveProcessOptions,
): Observable<ProcessMessage> {
return spawn(command, args, options).flatMap(proc =>
getOutputStream(proc, {...options, splitByLines: false}),
);
}
//
// # Lower-level APIs
//
// The following functions are used to create the higher-level APIs above. It's rare that you'll
// need to use them by themselves.
//
/**
* Creates an observable that spawns a process and emits it. Like with `runCommand()` and
* `observeProcess()`, if you unsubscribe from the returned observable, the process will be killed
* (or, if it hasn't yet been spawned, it won't be created).
*
* Unlike `observeProcess()`, the returned observable won't throw ProcessExitErrors--only system
* errors raised when trying to spawn the process. This is because it's meant to be composed with
* `getOutputStream` which terminates based on the "close" event whereas this terminates on the
* "exit" event to ensure that you don't try to interact with a dead process.
*
* This function is useful when, for example, you need access to the process in order to send IPC
* messages to it. It can be composed with `getOutputStream()` to give the same functionality of
* `observeProcess()`:
*
* ```js
* const subscription = spawn(...)
* .map(proc => {
* // With access to the process, you can send IPC messages.
*
* return getOutputStream(proc);
* })
* .subscribe(event => {
* // These events are the same as those emitted by `observeProcess()`.
* });
* ```
*/
export function spawn(
command: string,
args?: Array<string>,
options?: SpawnProcessOptions,
): Observable<child_process$ChildProcess> {
return createProcessStream('spawn', command, args, options);
}
/**
* Identical to `spawn()` (above), but uses `child_process.fork()` to create the process.
*/
export function fork(
modulePath: string,
args?: Array<string>,
options?: ForkProcessOptions,
): Observable<child_process$ChildProcess> {
return createProcessStream('fork', modulePath, args, options);
}
/**
* Creates a stream of sensibly-ordered stdout, stdin, and exit messages from a process. Generally,
* you shouldn't use this function and should instead use `observeProcess()` (which makes use of
* this for you).
*
* IMPORTANT: If you must use this function, it's very important that the process you give it was
* just synchronously created. Otherwise, you can end up missing messages.
*
* This function intentionally does not close the process when you unsubscribe. It's usually used in
* conjunction with `spawn()` which does that already.
*/
export function getOutputStream(
proc: child_process$ChildProcess,
options?: GetOutputStreamOptions,
rest: void,
): Observable<ProcessMessage> {
const chunk =
idx(options, _ => _.splitByLines) === false ? x => x : splitStream;
const maxBuffer = idx(options, _ => _.maxBuffer);
const isExitError = idx(options, _ => _.isExitError) || isExitErrorDefault;
const exitErrorBufferSize = idx(options, _ => _.exitErrorBufferSize) || 2000;
return Observable.defer(() => {
const stdoutEvents = chunk(
limitBufferSize(observeStream(proc.stdout), maxBuffer, 'stdout'),
).map(data => ({kind: 'stdout', data}));
const stderrEvents = chunk(
limitBufferSize(observeStream(proc.stderr), maxBuffer, 'stderr'),
)
.map(data => ({kind: 'stderr', data}))
.share();
// Accumulate the first `exitErrorBufferSize` bytes of stderr so that we can give feedback about
// about exit errors (then stop so we don't fill up memory with it).
const accumulatedStderr = stderrEvents
.scan(
(acc, event) => (acc + event.data).slice(0, exitErrorBufferSize),
'',
)
.startWith('')
.let(takeWhileInclusive(acc => acc.length < exitErrorBufferSize));
// We need to start listening for the exit event immediately, but defer emitting it until the
// (buffered) output streams end.
const closeEvents = Observable.fromEvent(
proc,
// We listen to the "close" event instead of "exit" because we want to get all of the stdout
// and stderr.
'close',
(exitCode: ?number, signal: ?string) => ({
kind: 'exit',
exitCode,
signal,
}),
)
.filter(isRealExit)
.take(1)
.withLatestFrom(accumulatedStderr)
.map(([event, stderr]) => {
if (isExitError(event)) {
throw new ProcessExitError(
event.exitCode,
event.signal,
proc,
stderr,
);
}
return event;
})
.publishReplay();
const exitSub = closeEvents.connect();
return Observable.merge(stdoutEvents, stderrEvents)
.concat(closeEvents)
.let(
takeWhileInclusive(
event => event.kind !== 'error' && event.kind !== 'exit',
),
)
.finally(() => {
exitSub.unsubscribe();
});
});
}
//
// # Miscellaneous Utilities
//
// The following utilities don't spawn processes or necessarily use observables. Instead, they're
// used to format arguments to the above functions or for acting on already-spawned processes.
//
/**
* Takes the arguments that you would normally pass to `spawn()` and returns an array of new
* arguments to use to run the command under `script`.
*
* Example:
*
* ```js
* observeProcess(...scriptifyCommand('hg', ['diff'])).subscribe(...);
* ```
*
* See also `nicifyCommand()` which does a similar thing but for `nice`.
*/
export function scriptifyCommand<T>(
command: string,
args?: Array<string> = [],
options: T,
): [string, Array<string>, T] {
if (process.platform === 'darwin') {
// On OS X, script takes the program to run and its arguments as varargs at the end.
return ['script', ['-q', '/dev/null', command].concat(args), options];
} else {
// On Linux, script takes the command to run as the -c parameter so we have to combine all of
// the arguments into a single string.
const joined = shellQuote([command, ...args]);
// flowlint-next-line sketchy-null-mixed:off
const opts = options || {};
// flowlint-next-line sketchy-null-mixed:off
const env = opts.env || {};
return [
'script',
['-q', '/dev/null', '-c', joined],
// `script` will use `SHELL`, but shells have different behaviors with regard to escaping. To
// make sure that out escaping is correct, we need to force a particular shell.
{...opts, env: {...env, SHELL: '/bin/bash'}},
];
}
}
/**
* Kills a process and, optionally, its descendants.
*/
export function killProcess(
proc: child_process$ChildProcess,
killTree: boolean,
killTreeSignal: ?string,
): void {
_killProcess(proc, killTree, killTreeSignal).then(
() => {},
error => {
logger.error(`Killing process ${proc.pid} failed`, error);
},
);
}
/**
* Kill the process with the provided pid.
*/
export function killPid(pid: number): void {
try {
process.kill(pid);
} catch (err) {
if (err.code !== 'ESRCH') {
throw err;
}
}
}
// Inside FB, Nuclide's RPC process doesn't inherit its parent environment and sets up its own instead.
// It does this to prevent difficult-to-diagnose issues caused by unexpected code in users' dotfiles.
// Before overwriting it, the original environment is base64-encoded in NUCLIDE_ORIGINAL_ENV.
// WARNING: This function returns the environment that would have been inherited under normal conditions.
// You can use it with a child process to let the user set its environment variables. By doing so, you are creating
// an even more complicated mess of inheritance and non-inheritance in the process tree.
let cachedOriginalEnvironment = null;
export async function getOriginalEnvironment(): Promise<Object> {
await new Promise(resolve => {
whenShellEnvironmentLoaded(resolve);
});
if (cachedOriginalEnvironment != null) {
return cachedOriginalEnvironment;
}
const {NUCLIDE_ORIGINAL_ENV} = process.env;
if (NUCLIDE_ORIGINAL_ENV != null && NUCLIDE_ORIGINAL_ENV.trim() !== '') {
const envString = new Buffer(NUCLIDE_ORIGINAL_ENV, 'base64').toString();
cachedOriginalEnvironment = {};
for (const envVar of envString.split('\0')) {
// envVar should look like A=value_of_A
const equalIndex = envVar.indexOf('=');
if (equalIndex !== -1) {
cachedOriginalEnvironment[
envVar.substring(0, equalIndex)
] = envVar.substring(equalIndex + 1);
}
}
// Guard against invalid original environments.
if (!Object.keys(cachedOriginalEnvironment).length) {
cachedOriginalEnvironment = process.env;
}
} else {
cachedOriginalEnvironment = process.env;
}
return cachedOriginalEnvironment;
}
// See getOriginalEnvironment above.
export async function getOriginalEnvironmentArray(): Promise<Array<string>> {
await new Promise(resolve => {
whenShellEnvironmentLoaded(resolve);
});
const {NUCLIDE_ORIGINAL_ENV} = process.env;
if (NUCLIDE_ORIGINAL_ENV != null && NUCLIDE_ORIGINAL_ENV.trim() !== '') {
const envString = new Buffer(NUCLIDE_ORIGINAL_ENV, 'base64').toString();
return envString.split('\0');
}
return [];
}
export async function getEnvironment(): Promise<Object> {
await new Promise(resolve => {
whenShellEnvironmentLoaded(resolve);
});
return process.env;
}
/**
* Returns a string suitable for including in displayed error messages.
*/
export function exitEventToMessage(event: {
exitCode: ?number,
signal: ?string,
}): string {
if (event.exitCode != null) {
return `exit code ${event.exitCode}`;
} else {
invariant(event.signal != null);
return `signal ${event.signal}`;
}
}
export async function getChildrenOfProcess(
processId: number,
): Promise<Array<ProcessInfo>> {
const processes = await psTree();
return processes.filter(processInfo => processInfo.parentPid === processId);
}
/**
* Get a list of descendants, sorted by increasing depth (including the one with the provided pid).
*/
async function getDescendantsOfProcess(
pid: number,
): Promise<Array<ProcessInfo>> {
const processes = await psTree();
let rootProcessInfo;
const pidToChildren = new MultiMap();
processes.forEach(info => {
if (info.pid === pid) {
rootProcessInfo = info;
}
pidToChildren.add(info.parentPid, info);
});
const descendants = rootProcessInfo == null ? [] : [rootProcessInfo];
// Walk through the array, adding the children of the current element to the end. This
// breadth-first traversal means that the elements will be sorted by depth.
for (let i = 0; i < descendants.length; i++) {
const info = descendants[i];
const children = pidToChildren.get(info.pid);
descendants.push(...Array.from(children));
}
return descendants;
}
export async function psTree(): Promise<Array<ProcessInfo>> {
if (isWindowsPlatform()) {
return psTreeWindows();
}
const [commands, withArgs] = await Promise.all([
runCommand('ps', ['-A', '-o', 'ppid,pid,comm']).toPromise(),
runCommand('ps', ['-A', '-ww', '-o', 'pid,args']).toPromise(),
]);
return parsePsOutput(commands, withArgs);
}
async function psTreeWindows(): Promise<Array<ProcessInfo>> {
const stdout = await runCommand('wmic.exe', [
'PROCESS',
'GET',
'ParentProcessId,ProcessId,Name',
]).toPromise();
return parsePsOutput(stdout);
}
export function parsePsOutput(
psOutput: string,
argsOutput: ?string,
): Array<ProcessInfo> {
// Remove the first header line.
const lines = psOutput
.trim()
.split(/\n|\r\n/)
.slice(1);
let withArgs = new Map();
if (argsOutput != null) {
withArgs = new Map(
argsOutput
.trim()
.split(/\n|\r\n/)
.slice(1)
.map(line => {
const columns = line.trim().split(/\s+/);
const pid = parseInt(columns[0], 10);
const command = columns.slice(1).join(' ');
return [pid, command];
}),
);
}
return lines.map(line => {
const columns = line.trim().split(/\s+/);
const [parentPid, pidStr] = columns;
const pid = parseInt(pidStr, 10);
const command = columns.slice(2).join(' ');
const commandWithArgs = withArgs.get(pid);
return {
command,
parentPid: parseInt(parentPid, 10),
pid,
commandWithArgs: commandWithArgs == null ? command : commandWithArgs,
};
});
}
// Use `ps` to get memory usage in kb for an array of process id's as a map.
export async function memoryUsagePerPid(
pids: Array<number>,
): Promise<Map<number, number>> {
const usage = new Map();
if (pids.length >= 1) {
try {
const stdout = await runCommand('ps', [
'-p',
pids.join(','),
'-o',
'pid=',
'-o',
'rss=',
]).toPromise();
stdout.split('\n').forEach(line => {
const parts = line.trim().split(/\s+/);
if (parts.length === 2) {
const [pid, rss] = parts.map(x => parseInt(x, 10));
usage.set(pid, rss);
}
});
} catch (err) {
// Ignore errors.
}
}
return usage;
}
/**
* Add no-op error handlers to the process's streams so that Node doesn't throw them.
*/
export function preventStreamsFromThrowing(
proc: child_process$ChildProcess,
): IDisposable {
return new UniversalDisposable(getStreamErrorEvents(proc).subscribe());
}
/**
* Log errors from a process's streams. This function returns an `rxjs$ISubscription` so that it
* can easily be used with `Observable.using()`.
*/
export function logStreamErrors(
proc: child_process$ChildProcess,
command: string,
args: Array<string>,
options?: Object,
): IDisposable & rxjs$ISubscription {
return new UniversalDisposable(
getStreamErrorEvents(proc)
.do(([err, streamName]) => {
logger.error(
`stream error on stream ${streamName} with command:`,
command,
args,
options,
'error:',
err,
);
})
.subscribe(),
);
}
//
// Types
//
// Exactly one of exitCode and signal will be non-null.
// Killing a process will result in a null exitCode but a non-null signal.
export type ProcessExitMessage = {
kind: 'exit',
exitCode: ?number,
signal: ?string,
};
export type ProcessMessage =
| {
kind: 'stdout',
data: string,
}
| {
kind: 'stderr',
data: string,
}
| ProcessExitMessage;
// In older versions of process.js, errors were emitted as messages instead of errors. This type
// exists to support the transition, but no new usages should be added.
export type LegacyProcessMessage =
| ProcessMessage
| {kind: 'error', error: Object};
export type ProcessInfo = {
parentPid: number,
pid: number,
command: string,
commandWithArgs: string,
};
export type Level = 'info' | 'log' | 'warning' | 'error' | 'debug' | 'success';
export type Message = {text: string, level: Level};
export type MessageEvent = {
type: 'message',
message: Message,
};
export type ProgressEvent = {
type: 'progress',
progress: ?number,
};
export type ResultEvent = {
type: 'result',
result: mixed,
};
export type StatusEvent = {
type: 'status',
status: ?string,
};
export type TaskEvent =
| MessageEvent
| ProgressEvent
| ResultEvent
| StatusEvent;
type CreateProcessStreamOptions = (
| child_process$spawnOpts
| child_process$forkOpts
) & {
killTreeWhenDone?: ?boolean,
killTreeSignal?: string,
timeout?: ?number,
input?: ?(string | Observable<string>),
dontLogInNuclide?: ?boolean,
};
type GetOutputStreamOptions = {
splitByLines?: ?boolean,
maxBuffer?: ?number,
exitErrorBufferSize?: ?number,
isExitError?: ?(event: ProcessExitMessage) => boolean,
};
export type ObserveProcessOptions = SpawnProcessOptions &
GetOutputStreamOptions;
export type SpawnProcessOptions = child_process$spawnOpts &
CreateProcessStreamOptions;
export type ForkProcessOptions = child_process$forkOpts &
CreateProcessStreamOptions;
export type ProcessError = ProcessSystemError | ProcessExitError;
//
// Errors
//
/**
* An error thrown by process utils when the process exits with an error code. This type has all the
* properties of ProcessExitMessage (except "kind").
*
* Note that the `stderr` property will only contain the complete stderr when thrown by the
* output-accumulating functions (`runCommand()`, `runCommandDetailed()`). For others, like
* `observeProcess()`, it will be truncated. Similarly, `stdout` will only be populated when the
* error is thrown by output-accumulating functions. For others, it will always be `null`.
*/
export class ProcessExitError extends Error {
exitCode: ?number;
signal: ?string;
stderr: string;
stdout: ?string;
command: string;
args: Array<string>;
process: child_process$ChildProcess;
constructor(
exitCode: ?number,
signal: ?string,
proc: child_process$ChildProcess,
stderr: string,
stdout?: string,
) {
// $FlowIssue: This isn't typed in the Flow node type defs
const {spawnargs} = proc;
const argsAndCommand =
spawnargs[0] === process.execPath ? spawnargs.slice(1) : spawnargs;
const [command, ...args] = argsAndCommand;
super(
`"${command}" failed with ${exitEventToMessage({
exitCode,
signal,
})}\n\n${stderr}\n\n${argsAndCommand.join(' ')}`,
);
this.name = 'ProcessExitError';
this.exitCode = exitCode;
this.signal = signal;
this.stderr = stderr;
this.stdout = stdout;
this.command = command;
this.args = args;
this.process = proc;
}
}
/**
* Process system errors are just augmented Error objects. We wrap the errors and expose the process
* since our utilities throw the errors before returning the process.
*/
export class ProcessSystemError extends Error {
errno: number | string;
code: string;
path: ?string;
syscall: ?string;
process: child_process$ChildProcess;
constructor(err: any, proc: child_process$ChildProcess) {
super(err.message);
this.name = 'ProcessSystemError';
this.errno = err.errno;
this.code = err.code;
this.path = err.path;
this.syscall = err.syscall;
this.process = proc;
}
}
export class MaxBufferExceededError extends Error {
constructor(streamName: string) {
super(`${streamName} maxBuffer exceeded`);
this.name = 'MaxBufferExceededError';
}
}
export class ProcessTimeoutError extends Error {
constructor(timeout: number, proc: child_process$ChildProcess) {
// $FlowIssue: This isn't typed in the Flow node type defs
const {spawnargs} = proc;
const commandName =
spawnargs[0] === process.execPath ? spawnargs[1] : spawnargs[0];
super(`"${commandName}" timed out after ${timeout}ms`);
this.name = 'ProcessTimeoutError';
}
}
//
// Internal Stuff
//
// Pay no attention! This is just stuff that's used internally to implement the good stuff.
//
// Node crashes if we allow buffers that are too large.
const DEFAULT_MAX_BUFFER = 100 * 1024 * 1024;
const MAX_LOGGED_CALLS = 100;
const NUM_PRESERVED_HISTORY_CALLS = 50;
const noopDisposable = {dispose: () => {}};
const whenShellEnvironmentLoaded =
typeof atom !== 'undefined' && !atom.inSpecMode()
? atom.whenShellEnvironmentLoaded.bind(atom)
: cb => {
cb();
return noopDisposable;
};
/**
* Log custom events to log4js so that we can easily hook into process events
* using a custom log4js appender (e.g. for analytics purposes).
*/
export class ProcessLoggingEvent {
command: string;
duration: number;
constructor(command: string, duration: number) {
this.command = command;
this.duration = duration;
// log4js uses util.inspect to convert log arguments to strings.
// Note: computed property methods aren't supported by Flow yet.
(this: any)[util.inspect.custom] = () => {
return `${this.duration}ms: ${this.command}`;
};
}
}
export const loggedCalls = [];
function logCall(duration: number, command: string, args: Array<string>) {
// Trim the history once in a while, to avoid doing expensive array
// manipulation all the time after we reached the end of the history
if (loggedCalls.length > MAX_LOGGED_CALLS) {
loggedCalls.splice(0, loggedCalls.length - NUM_PRESERVED_HISTORY_CALLS, {
command: '... history stripped ...',
duration: 0,
time: new Date(),
});
}
const fullCommand = shellQuote([command, ...args]);
loggedCalls.push({
command: fullCommand,
duration,
time: new Date(),
});
logger.info(new ProcessLoggingEvent(fullCommand, duration));
}
/**
* Attempt to get the fully qualified binary name from a process id. This is
* surprisingly tricky. 'ps' only reports the path as invoked, and in some cases
* not even that.
*
* On Linux, the /proc filesystem can be used to find it.
* macOS doesn't have /proc, so we rely on the fact that the process holds
* an open FD to the executable. This can fail for various reasons (mostly
* not having permissions to execute lsof on the pid.)
*/
export async function getAbsoluteBinaryPathForPid(
pid: number,
): Promise<?string> {
if (process.platform === 'linux') {
return _getLinuxBinaryPathForPid(pid);
}
if (process.platform === 'darwin') {
return _getDarwinBinaryPathForPid(pid);
}
return null;
}
async function _getLinuxBinaryPathForPid(pid: number): Promise<?string> {
const exeLink = `/proc/${pid}/exe`;
// /proc/xxx/exe is a symlink to the real binary in the file system.
return runCommand('/bin/realpath', ['-q', '-e', exeLink])
.catch(_ => Observable.of(null))
.toPromise();
}
async function _getDarwinBinaryPathForPid(pid: number): Promise<?string> {
return runCommand('/usr/sbin/lsof', ['-p', `${pid}`])
.catch(_ => {
return Observable.of(null);
})
.map(
stdout =>
stdout == null
? null
: stdout
.split('\n')
.map(line => line.trim().split(/\s+/))
.filter(line => line[3] === 'txt')
.map(line => line[8])[0],
)
.take(1)
.toPromise();
}
/**
* Creates an observable with the following properties:
*
* 1. It contains a process that's created using the provided factory when you subscribe.
* 2. It doesn't complete until the process exits (or errors).
* 3. The process is killed when you unsubscribe.
*
* This means that a single observable instance can be used to spawn multiple processes. Indeed, if
* you subscribe multiple times, multiple processes *will* be spawned.
*
* IMPORTANT: The exit event does NOT mean that all stdout and stderr events have been received.
*/
function createProcessStream(
type: 'spawn' | 'fork' = 'spawn',
commandOrModulePath: string,
args?: Array<string> = [],
options?: CreateProcessStreamOptions = {},
): Observable<child_process$ChildProcess> {
const inputOption = options.input;
let input;