-
Notifications
You must be signed in to change notification settings - Fork 269
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
fix(stream-transform): backpressure after push
- Loading branch information
Showing
11 changed files
with
160 additions
and
82 deletions.
There are no files selected for viewing
This file was deleted.
Oops, something went wrong.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,88 @@ | ||
| import { Writable } from "node:stream"; | ||
| import { pipeline } from "stream/promises"; | ||
| import { generate } from "csv-generate"; | ||
| import { transform } from "stream-transform"; | ||
|
|
||
| // Configuration | ||
| const config = { | ||
| // Use `true`for a simple iterator or `false` to use csv generate | ||
| iterate: true, | ||
| // Generation window size, 1 for one record per `StreamReader._read` call | ||
| // Default is `objectMode ? 16 : 16384` | ||
| highWaterMark: 1, | ||
| // Number of records to generate, `-1` for infinite | ||
| length: -1, | ||
| // Generate object or strings, both are supported | ||
| objectMode: false, | ||
| // Write delay, `0` to write instantly | ||
| write_delay: 1000, | ||
| }; | ||
|
|
||
| // Internal counter | ||
| let count = 0; | ||
|
|
||
| // Memory information | ||
| const formatMemoryUsage = (data) => | ||
| `${Math.round((data / 1024 / 1024) * 100) / 100} MB`; | ||
| const interval = setInterval(() => { | ||
| const memoryData = process.memoryUsage(); | ||
| const memoryUsage = { | ||
| rss: `${formatMemoryUsage( | ||
| memoryData.rss | ||
| )} -> Resident Set Size - total memory allocated for the process execution`, | ||
| heapTotal: `${formatMemoryUsage( | ||
| memoryData.heapTotal | ||
| )} -> total size of the allocated heap`, | ||
| heapUsed: `${formatMemoryUsage( | ||
| memoryData.heapUsed | ||
| )} -> actual memory used during the execution`, | ||
| external: `${formatMemoryUsage(memoryData.external)} -> V8 external memory`, | ||
| }; | ||
| console.log(`${count} records, usage:`, memoryUsage); | ||
| if (config.length !== -1 && count >= config.length) { | ||
| clearInterval(interval); | ||
| } | ||
| }, 1000); | ||
|
|
||
| // Iterate over an unlimited records | ||
| const iterate = function* () { | ||
| let i = -1; | ||
| // Run with | ||
| while (true) { | ||
| i++; | ||
| yield { i }; | ||
| } | ||
| }; | ||
|
|
||
| // Consome the records instantly or with delay | ||
| const consume = new Writable({ | ||
| write: function (_, __, callback) { | ||
| if (config.write_delay === 0) { | ||
| count++; | ||
| callback(); | ||
| } else { | ||
| setTimeout(() => { | ||
| count++; | ||
| callback(); | ||
| }, config.write_delay); | ||
| } | ||
| }, | ||
| }); | ||
|
|
||
| await pipeline( | ||
| // Step 1 - generate | ||
| config.iterate | ||
| ? iterate() | ||
| : generate({ | ||
| columns: 10, | ||
| objectMode: config.objectMode, | ||
| length: config.length, | ||
| highWaterMark: config.highWaterMark, | ||
| }), | ||
| // Step 2 - transform | ||
| transform({ parallel: 100, highWaterMark: 1 }, function (chunk, next) { | ||
| next(null, JSON.stringify(chunk) + "\n"); | ||
| }), | ||
| // Step 3 - consume | ||
| consume | ||
| ); |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.