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fix(core): When piping a stream to multiple destinations, do so safely
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,70 +1,75 @@ | ||
| import { PassThrough } from 'stream' | ||
| import { Readable, PassThrough } from 'stream' | ||
| import { ChildProcessWithoutNullStreams } from 'child_process' | ||
| import { once } from 'events' | ||
| import mergeStream from 'merge-stream' | ||
| import splitStream from 'split' | ||
| import { NormalizedServiceConfig } from './validateAndNormalizeConfig' | ||
| import { spawnProcess } from './spawnProcess' | ||
|
|
||
| const split = () => splitStream((line: string) => `${line}\n`) | ||
|
|
||
| export class ServiceProcess { | ||
| public readonly output = new PassThrough({ objectMode: true }) | ||
| public readonly started: Promise<void> | ||
| public isEnded = false | ||
| public logTail: string[] = [] | ||
| private readonly process: ChildProcessWithoutNullStreams | ||
| private didError = false | ||
| private didEnd = false | ||
| private readonly ended: Promise<void> | ||
| private wasEndCalled = false | ||
| constructor(config: NormalizedServiceConfig, onCrash: () => void) { | ||
| this.process = spawnProcess(config) | ||
| const childOutput = mergeStream( | ||
| this.process.stdout.setEncoding('utf8').pipe(split()), | ||
| this.process.stderr.setEncoding('utf8').pipe(split()) | ||
| ) | ||
| childOutput.pipe(this.output) | ||
| if (config.logTailLength > 0) { | ||
| this.output.on('data', line => { | ||
| this.logTail.push(line) | ||
| if (this.logTail.length > config.logTailLength) { | ||
| this.logTail.shift() | ||
| } | ||
| }) | ||
| } | ||
| const error = new Promise(resolve => this.process.on('error', resolve)) | ||
| this.started = Promise.race([ | ||
| error, | ||
| new Promise(resolve => setTimeout(resolve, 100)), | ||
| new Promise(resolve => this.process.once('error', resolve)), | ||
| new Promise(resolve => setTimeout(() => resolve(), 100)), | ||
| ]).then(error => { | ||
| if (!error) { | ||
| return | ||
| if (error) { | ||
| this.didError = true | ||
| throw error | ||
| } | ||
| childOutput.unpipe(this.output) | ||
| this.output.end() | ||
| return Promise.reject(error) | ||
| }) | ||
| const didStart = this.started.then( | ||
| () => true, | ||
| () => false | ||
| const processOutput = mergeStream( | ||
| transformStream(this.process.stdout), | ||
| transformStream(this.process.stderr) | ||
| ) | ||
| this.ended = Promise.race([error, once(childOutput, 'end')]).then(() => { | ||
| this.isEnded = true | ||
| if (!this.wasEndCalled) { | ||
| didStart.then(didStart => { | ||
| if (didStart) { | ||
| onCrash() | ||
| this.ended = (async () => { | ||
| for await (const line of processOutput as AsyncIterable<string>) { | ||
| if (this.didError) { | ||
| break | ||
| } | ||
| this.output.write(line) | ||
| if (config.logTailLength > 0) { | ||
| this.logTail.push(line) | ||
| if (this.logTail.length > config.logTailLength) { | ||
| this.logTail.shift() | ||
| } | ||
| }) | ||
| } | ||
| } | ||
| this.didEnd = true | ||
| this.output.end() | ||
| })() | ||
| Promise.all([this.started.catch(() => {}), this.ended]).then(() => { | ||
| if (!this.didError && !this.wasEndCalled) { | ||
| onCrash() | ||
| } | ||
| }) | ||
| } | ||
| end() { | ||
| public isRunning() { | ||
| return !this.didError && !this.didEnd | ||
| } | ||
| public end() { | ||
| if (!this.wasEndCalled) { | ||
| this.wasEndCalled = true | ||
| if (!this.isEnded) { | ||
| if (this.isRunning()) { | ||
| this.process.kill('SIGINT') | ||
| } | ||
| } | ||
| return this.ended | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * Split input into stream of utf8 strings ending in '\n' | ||
| * */ | ||
| function transformStream(input: Readable): Readable { | ||
| return input | ||
| .setEncoding('utf8') | ||
| .pipe(splitStream((line: string) => `${line}\n`)) | ||
| } |
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