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@ehmicky
ehmicky committed Sep 4, 2024
1 parent 865d71e commit 65a7049
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Showing 5 changed files with 196 additions and 190 deletions.
19 changes: 19 additions & 0 deletions source/context.js
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import process from 'node:process';
import {stripVTControlCharacters} from 'node:util';

export const getContext = (previous, rawFile, rawArguments) => {
const start = previous.start ?? process.hrtime.bigint();
const command = [previous.command, getCommand(rawFile, rawArguments)].filter(Boolean).join(' | ');
return {start, command, state: {stdout: '', stderr: '', output: ''}};
};

const getCommand = (rawFile, rawArguments) => [rawFile, ...rawArguments]
.map(part => getCommandPart(part))
.join(' ');

const getCommandPart = part => {
part = stripVTControlCharacters(part);
return /[^\w./-]/.test(part)
? `'${part.replaceAll('\'', '\'\\\'\'')}'`
: part;
};
201 changes: 11 additions & 190 deletions source/index.js
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@@ -1,26 +1,19 @@
import {spawn} from 'node:child_process';
import {once, on} from 'node:events';
import {stripVTControlCharacters} from 'node:util';
import path from 'node:path';
import process from 'node:process';
import {fileURLToPath} from 'node:url';
import {lineIterator, combineAsyncIterators} from './iterable.js';
import {getForcedShell, escapeArguments} from './windows.js';
import {getContext} from './context.js';
import {getOptions} from './options.js';
import {spawnSubprocess} from './spawn.js';
import {getResult} from './result.js';
import {handlePipe} from './pipe.js';
import {lineIterator, combineAsyncIterators} from './iterable.js';

export default function nanoSpawn(first, second = [], third = {}) {
let [file, previous] = Array.isArray(first) ? first : [first, {}];
let [commandArguments, options] = Array.isArray(second) ? [second, third] : [[], second];
const [rawFile, previous] = Array.isArray(first) ? first : [first, {}];
const [rawArguments, options] = Array.isArray(second) ? [second, third] : [[], second];

const start = previous.start ?? process.hrtime.bigint();
const context = getContext(previous, rawFile, rawArguments);
const spawnOptions = getOptions(options);
const command = [previous.command, getCommand(file, commandArguments)].filter(Boolean).join(' | ');
const context = {start, command, state: initState()};
[file, commandArguments] = handleNode(file, commandArguments);
const input = getInput(spawnOptions);

const nodeChildProcess = getInstance(file, commandArguments, spawnOptions, context);
const resultPromise = Object.assign(getResult(nodeChildProcess, input, context), {nodeChildProcess});
const nodeChildProcess = spawnSubprocess(rawFile, rawArguments, spawnOptions, context);
const resultPromise = getResult(nodeChildProcess, spawnOptions, context);
Object.assign(resultPromise, {nodeChildProcess});
const finalPromise = previous.resultPromise === undefined ? resultPromise : handlePipe(previous, resultPromise);

const stdoutLines = lineIterator(finalPromise, context, 'stdout');
Expand All @@ -32,175 +25,3 @@ export default function nanoSpawn(first, second = [], third = {}) {
pipe: (file, second, third) => nanoSpawn([file, {...context, resultPromise: finalPromise}], second, third),
});
}

const getOptions = ({
stdin,
stdout,
stderr,
stdio = [stdin, stdout, stderr],
env: envOption,
preferLocal,
cwd: cwdOption = '.',
...options
}) => {
const cwd = cwdOption instanceof URL ? fileURLToPath(cwdOption) : path.resolve(cwdOption);
const env = envOption === undefined ? undefined : {...process.env, ...envOption};
return {
...options,
stdio,
env: preferLocal ? addLocalPath(env ?? process.env, cwd) : env,
cwd,
};
};

const addLocalPath = ({Path = '', PATH = Path, ...env}, cwd) => {
const pathParts = PATH.split(path.delimiter);
const localPaths = getLocalPaths([], path.resolve(cwd))
.map(localPath => path.join(localPath, 'node_modules/.bin'))
.filter(localPath => !pathParts.includes(localPath));
return {...env, PATH: [...localPaths, PATH].filter(Boolean).join(path.delimiter)};
};

const getLocalPaths = (localPaths, localPath) => localPaths.at(-1) === localPath
? localPaths
: getLocalPaths([...localPaths, localPath], path.resolve(localPath, '..'));

// When running `node`, keep the current Node version and CLI flags.
// Not applied with file paths to `.../node` since those indicate a clear intent to use a specific Node version.
// Does not work with shebangs, but those don't work cross-platform anyway.
const handleNode = (file, commandArguments) => file.toLowerCase().replace(/\.exe$/, '') === 'node'
? [process.execPath, [...process.execArgv.filter(flag => !flag.startsWith('--inspect')), ...commandArguments]]
: [file, commandArguments];

const getCommand = (file, commandArguments) => [file, ...commandArguments]
.map(part => getCommandPart(part))
.join(' ');

const getCommandPart = part => {
part = stripVTControlCharacters(part);
return /[^\w./-]/.test(part)
? `'${part.replaceAll('\'', '\'\\\'\'')}'`
: part;
};

const getInput = ({stdio}) => {
if (stdio[0]?.string === undefined) {
return;
}

const input = stdio[0].string;
stdio[0] = 'pipe';
return input;
};

const getInstance = async (file, commandArguments, spawnOptions, context) => {
try {
const forcedShell = await getForcedShell(file, spawnOptions);
spawnOptions.shell ||= forcedShell;
const instance = spawn(...escapeArguments(file, commandArguments, forcedShell), spawnOptions);
bufferOutput(instance.stdout, context, 'stdout');
bufferOutput(instance.stderr, context, 'stderr');

// The `error` event is caught by `once(instance, 'spawn')` and `once(instance, 'close')`.
// But it creates an uncaught exception if it happens exactly one tick after 'spawn'.
// This prevents that.
instance.once('error', () => {});

await once(instance, 'spawn');
return instance;
} catch (error) {
throw getResultError(error, initState(), context);
}
};

const getResult = async (nodeChildProcess, input, context) => {
const instance = await nodeChildProcess;
useInput(instance, input);
const onClose = once(instance, 'close');

try {
await Promise.race([onClose, ...onStreamErrors(instance)]);
checkFailure(context, getErrorOutput(instance));
return getOutputs(context);
} catch (error) {
await Promise.allSettled([onClose]);
throw getResultError(error, instance, context);
}
};

const useInput = (instance, input) => {
if (input !== undefined) {
instance.stdin.end(input);
}
};

const initState = () => ({stdout: '', stderr: '', output: ''});

const bufferOutput = (stream, {state}, streamName) => {
if (!stream) {
return;
}

stream.setEncoding('utf8');
if (state.isIterating) {
return;
}

state.isIterating = false;
stream.on('data', chunk => {
for (const outputName of [streamName, 'output']) {
state[outputName] += chunk;
}
});
};

const onStreamErrors = ({stdio}) => stdio.filter(Boolean).map(stream => onStreamError(stream));

const onStreamError = async stream => {
for await (const [error] of on(stream, 'error')) {
if (!IGNORED_CODES.has(error?.code)) {
throw error;
}
}
};

// Ignore errors that are due to closing errors when the subprocesses exit normally, or due to piping
const IGNORED_CODES = new Set(['ERR_STREAM_PREMATURE_CLOSE', 'EPIPE']);

const getResultError = (error, instance, context) => Object.assign(
getErrorInstance(error, context),
getErrorOutput(instance),
getOutputs(context),
);

const getErrorInstance = (error, {command}) => error?.message.startsWith('Command ')
? error
: new Error(`Command failed: ${command}`, {cause: error});

const getErrorOutput = ({exitCode, signalCode}) => ({
// `exitCode` can be a negative number (`errno`) when the `error` event is emitted on the `instance`
...(exitCode === null || exitCode < 1 ? {} : {exitCode}),
...(signalCode === null ? {} : {signalName: signalCode}),
});

const getOutputs = ({state: {stdout, stderr, output}, command, start}) => ({
stdout: getOutput(stdout),
stderr: getOutput(stderr),
output: getOutput(output),
command,
durationMs: Number(process.hrtime.bigint() - start) / 1e6,
});

const getOutput = input => input?.at(-1) === '\n'
? input.slice(0, input.at(-2) === '\r' ? -2 : -1)
: input;

const checkFailure = ({command}, {exitCode, signalName}) => {
if (signalName !== undefined) {
throw new Error(`Command was terminated with ${signalName}: ${command}`);
}

if (exitCode !== undefined) {
throw new Error(`Command failed with exit code ${exitCode}: ${command}`);
}
};
39 changes: 39 additions & 0 deletions source/options.js
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import path from 'node:path';
import {fileURLToPath} from 'node:url';
import process from 'node:process';

export const getOptions = ({
stdin,
stdout,
stderr,
stdio = [stdin, stdout, stderr],
env: envOption,
preferLocal,
cwd: cwdOption = '.',
...options
}) => {
const cwd = cwdOption instanceof URL ? fileURLToPath(cwdOption) : path.resolve(cwdOption);
const env = envOption === undefined ? undefined : {...process.env, ...envOption};
const [stdioOption, input] = stdio[0]?.string === undefined
? [stdio]
: [['pipe', ...stdio.slice(1)], stdio[0].string];
return {
...options,
stdio: stdioOption,
input,
env: preferLocal ? addLocalPath(env ?? process.env, cwd) : env,
cwd,
};
};

const addLocalPath = ({Path = '', PATH = Path, ...env}, cwd) => {
const pathParts = PATH.split(path.delimiter);
const localPaths = getLocalPaths([], path.resolve(cwd))
.map(localPath => path.join(localPath, 'node_modules/.bin'))
.filter(localPath => !pathParts.includes(localPath));
return {...env, PATH: [...localPaths, PATH].filter(Boolean).join(path.delimiter)};
};

const getLocalPaths = (localPaths, localPath) => localPaths.at(-1) === localPath
? localPaths
: getLocalPaths([...localPaths, localPath], path.resolve(localPath, '..'));
74 changes: 74 additions & 0 deletions source/result.js
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import {once, on} from 'node:events';
import process from 'node:process';

export const getResult = async (nodeChildProcess, options, context) => {
const instance = await nodeChildProcess;
useInput(instance, options);
const onClose = once(instance, 'close');

try {
await Promise.race([onClose, ...onStreamErrors(instance)]);
checkFailure(context, getErrorOutput(instance));
return getOutputs(context);
} catch (error) {
await Promise.allSettled([onClose]);
throw getResultError(error, instance, context);
}
};

const useInput = (instance, {input}) => {
if (input !== undefined) {
instance.stdin.end(input);
}
};

const onStreamErrors = ({stdio}) => stdio.filter(Boolean).map(stream => onStreamError(stream));

const onStreamError = async stream => {
for await (const [error] of on(stream, 'error')) {
if (!IGNORED_CODES.has(error?.code)) {
throw error;
}
}
};

// Ignore errors that are due to closing errors when the subprocesses exit normally, or due to piping
const IGNORED_CODES = new Set(['ERR_STREAM_PREMATURE_CLOSE', 'EPIPE']);

export const getResultError = (error, instance, context) => Object.assign(
getErrorInstance(error, context),
getErrorOutput(instance),
getOutputs(context),
);

const getErrorInstance = (error, {command}) => error?.message.startsWith('Command ')
? error
: new Error(`Command failed: ${command}`, {cause: error});

const getErrorOutput = ({exitCode, signalCode}) => ({
// `exitCode` can be a negative number (`errno`) when the `error` event is emitted on the `instance`
...(exitCode === null || exitCode < 1 ? {} : {exitCode}),
...(signalCode === null ? {} : {signalName: signalCode}),
});

const getOutputs = ({state: {stdout, stderr, output}, command, start}) => ({
stdout: getOutput(stdout),
stderr: getOutput(stderr),
output: getOutput(output),
command,
durationMs: Number(process.hrtime.bigint() - start) / 1e6,
});

const getOutput = input => input?.at(-1) === '\n'
? input.slice(0, input.at(-2) === '\r' ? -2 : -1)
: input;

const checkFailure = ({command}, {exitCode, signalName}) => {
if (signalName !== undefined) {
throw new Error(`Command was terminated with ${signalName}: ${command}`);
}

if (exitCode !== undefined) {
throw new Error(`Command failed with exit code ${exitCode}: ${command}`);
}
};
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