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stream: complete pipeline with stdio #32373

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ronag wants to merge 13 commits into from
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stream: complete pipeline with stdio #32373

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571e867
stream: complete pipeline with stdio
ronag Mar 19, 2020
ab76605
fixup: isStdio helper
ronag Mar 19, 2020
84cf2aa
fixup: test
ronag Mar 19, 2020
b2925d8
fixup: typo
ronag Mar 19, 2020
bb882a2
fixup: test
ronag Mar 19, 2020
1d0a7a5
fixup: unhandledRejection
ronag Mar 19, 2020
3444617
fixup: faster version
ronag Mar 19, 2020
e9e4444
fixup: unify
ronag Mar 19, 2020
d9d992a
fixup: end stdio
ronag Mar 20, 2020
1498bb3
fixup
ronag Apr 6, 2020
2feb611
fixup
ronag Apr 6, 2020
e2ef9c9
fixup
ronag Apr 6, 2020
51d45eb
fixup
ronag Apr 6, 2020
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37 changes: 29 additions & 8 deletions lib/internal/streams/pipeline.js
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,8 @@
const {
ArrayIsArray,
SymbolAsyncIterator,
SymbolIterator
SymbolIterator,
Promise
} = primordials;

let eos;
Expand Down Expand Up @@ -113,6 +114,10 @@ function isStream(obj) {
return isReadable(obj) || isWritable(obj);
}

function isStdio(obj) {
return obj === process.stdout || obj === process.stderr;
}

function isIterable(obj, isAsync) {
if (!obj) return false;
if (isAsync === true) return typeof obj[SymbolAsyncIterator] === 'function';
Expand Down Expand Up @@ -147,13 +152,29 @@ async function pump(iterable, writable, finish) {
}
let error;
try {
for await (const chunk of iterable) {
if (!writable.write(chunk)) {
if (writable.destroyed) return;
await EE.once(writable, 'drain');
if (!isStdio(writable)) {
for await (const chunk of iterable) {
if (!writable.write(chunk)) {
if (writable.destroyed) return;
await EE.once(writable, 'drain');
}
}
writable.end();
} else {
const errorPromise = new Promise((resolve, reject) => {
writable.on('error', reject);
});
for await (const chunk of iterable) {
await Promise.race([
errorPromise,
new Promise((resolve, reject) => {
writable.write(chunk, null, (err) => {
err ? reject(err) : resolve();
});
})
]);
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@BridgeAR BridgeAR Mar 19, 2020

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It is likely faster to use the callbacks and manually handle everything. It could be wrapped in a single promise to allow to await the result for simplicity. Alternatively just also handle the finish call separately.

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@ronag ronag Mar 19, 2020

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It is likely faster to use the callbacks and manually handle everything. It could be wrapped in a single promise to allow to await the result for simplicity

Yes, but that makes the implementation more complicated... at least as far as I can determine.

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@ronag ronag Mar 19, 2020

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@BridgeAR PTAL

}
}
writable.end();
} catch (err) {
error = err;
} finally {
Expand Down Expand Up @@ -202,7 +223,7 @@ function pipeline(...streams) {
const reading = i < streams.length - 1;
const writing = i > 0;

if (isStream(stream)) {
if (isStream(stream) && !isStdio(stream)) {
finishCount++;
destroys.push(destroyer(stream, reading, writing, !reading, finish));
}
Expand Down Expand Up @@ -263,7 +284,7 @@ function pipeline(...streams) {
destroys.push(destroyer(ret, false, true, true, finish));
}
} else if (isStream(stream)) {
if (isReadable(ret)) {
if (isReadable(ret) && !isStdio(stream)) {
ret.pipe(stream);
} else {
ret = makeAsyncIterable(ret);
Expand Down
27 changes: 27 additions & 0 deletions test/parallel/test-stream-pipeline-process.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
'use strict';

const common = require('../common');
const assert = require('assert');

if (process.argv[2] === 'child') {
const { pipeline } = require('stream');
pipeline(
process.stdin,
process.stdout,
common.mustCall((err) => {
assert.ifError(err);
})
);
} else {
const cp = require('child_process');
cp.exec([
'echo',
'"hello"',
'|',
`"${process.execPath}"`,
`"${__filename}"`,
'child'
].join(' '), common.mustCall((err) => {
assert.ifError(err);
}));
}