concurrently
Version:
Run commands concurrently
185 lines (184 loc) • 5.89 kB
JavaScript
import process from 'node:process';
import Rx from 'rxjs';
export class Command {
killProcess;
spawn;
spawnOpts;
index;
/** @inheritdoc */
name;
/** @inheritdoc */
command;
/** @inheritdoc */
prefixColor;
/** @inheritdoc */
env;
/** @inheritdoc */
cwd;
/** @inheritdoc */
ipc;
close = new Rx.Subject();
error = new Rx.Subject();
stdout = new Rx.Subject();
stderr = new Rx.Subject();
timer = new Rx.Subject();
/**
* A stream of changes to the `#state` property.
*
* Note that the command never goes back to the `stopped` state, therefore it's not a value
* that's emitted by this stream.
*/
stateChange = new Rx.Subject();
messages = {
incoming: new Rx.Subject(),
outgoing: new Rx.ReplaySubject(),
};
process;
// TODO: Should exit/error/stdio subscriptions be added here?
subscriptions = [];
stdin;
pid;
killed = false;
exited = false;
state = 'stopped';
constructor({ index, name, command, prefixColor, env, cwd, ipc }, spawnOpts, spawn, killProcess) {
this.index = index;
this.name = name;
this.command = command;
this.prefixColor = prefixColor;
this.env = env || {};
this.cwd = cwd;
this.ipc = ipc;
this.killProcess = killProcess;
this.spawn = spawn;
this.spawnOpts = spawnOpts;
}
/**
* Starts this command, piping output, error and close events onto the corresponding observables.
*/
start() {
const child = this.spawn(this.command, this.spawnOpts);
this.changeState('started');
this.process = child;
this.pid = child.pid;
const startDate = new Date(Date.now());
const highResStartTime = process.hrtime();
this.timer.next({ startDate });
this.subscriptions = [...this.maybeSetupIPC(child)];
Rx.fromEvent(child, 'error').subscribe((event) => {
this.cleanUp();
const endDate = new Date(Date.now());
this.timer.next({ startDate, endDate });
this.error.next(event);
this.changeState('errored');
});
Rx.fromEvent(child, 'close')
.pipe(Rx.map((event) => event))
.subscribe(([exitCode, signal]) => {
this.cleanUp();
// Don't override error event
if (this.state !== 'errored') {
this.changeState('exited');
}
const endDate = new Date(Date.now());
this.timer.next({ startDate, endDate });
const [durationSeconds, durationNanoSeconds] = process.hrtime(highResStartTime);
this.close.next({
command: this,
index: this.index,
exitCode: exitCode ?? String(signal),
killed: this.killed,
timings: {
startDate,
endDate,
durationSeconds: durationSeconds + durationNanoSeconds / 1e9,
},
});
});
if (child.stdout) {
pipeTo(Rx.fromEvent(child.stdout, 'data').pipe(Rx.map((event) => event)), this.stdout);
}
if (child.stderr) {
pipeTo(Rx.fromEvent(child.stderr, 'data').pipe(Rx.map((event) => event)), this.stderr);
}
this.stdin = child.stdin || undefined;
}
changeState(state) {
this.state = state;
this.stateChange.next(state);
}
maybeSetupIPC(child) {
if (!this.ipc) {
return [];
}
return [
pipeTo(Rx.fromEvent(child, 'message').pipe(Rx.map((event) => {
const [message, handle] = event;
return { message, handle };
})), this.messages.incoming),
this.messages.outgoing.subscribe((message) => {
if (!child.send) {
return message.onSent(new Error('Command does not have an IPC channel'));
}
child.send(message.message, message.handle, message.options, (error) => {
message.onSent(error);
});
}),
];
}
/**
* Sends a message to the underlying process once it starts.
*
* @throws If the command doesn't have an IPC channel enabled
* @returns Promise that resolves when the message is sent,
* or rejects if it fails to deliver the message.
*/
send(message, handle, options) {
if (this.ipc == null) {
throw new Error('Command IPC is disabled');
}
return new Promise((resolve, reject) => {
this.messages.outgoing.next({
message,
handle,
options,
onSent(error) {
if (error) {
reject(error);
}
else {
resolve();
}
},
});
});
}
/**
* Kills this command, optionally specifying a signal to send to it.
*/
kill(code) {
if (Command.canKill(this)) {
this.killed = true;
this.killProcess(this.pid, code);
}
}
cleanUp() {
this.subscriptions?.forEach((sub) => sub.unsubscribe());
this.messages.outgoing = new Rx.ReplaySubject();
this.process = undefined;
}
/**
* Detects whether a command can be killed.
*
* Also works as a type guard on the input `command`.
*/
static canKill(command) {
return !!command.pid && !!command.process;
}
}
/**
* Pipes all events emitted by `stream` into `subject`.
*/
function pipeTo(stream, subject) {
return stream.subscribe((event) => subject.next(event));
}