redis-streams

Extends the redis client ioredis with streaming functions. This library allows to read and write data into redis via node streams. The implementation is inspired by redis-rstream and redis-wstream by @jeffbski and has been simplified, made type safe with TypeScript and includes additional features. This library can be conveniently used with async/await promise syntax.

The write stream has ben enhanced to include automatic generation of cryptographic hashes such as sha1 and others. Furthermore the redis key can be automatically set to the self-generated hash to allow for integrity checks and easy lookups.

If the maxBytes option is set on the write stream, an exception is thrown if the stream exceeds that upper limit. You can also set the TTL option, in order to automatically remove the data from the cache once the key is expired.

The main benefit of streaming is more efficient memory usage and safe-guards against buffer overflows. Performance gains vary based on your hardware and depend on both data and chunk sizes. The default chunk size has been set to 1 MB and can be changed through the options. Performance gains in my tests were approximately 20% for writing into the redis cache and insignificant during reading from the cache.

Installation

yarn add @jamify/redis-streams

Quick start

import { StreamIORedis } from '@jamify/redis-streams'

const redisClient = new StreamIORedis()

redisClient.readStream(key)
  .pipe(createWriteStream('image.jpg'))
  .on('finish', done)

createReadStream('image.jpg')
  .pipe(redisClient.writeStream(key))
  .on('finish', done)

// promise version of writeStream
await writeStreamPromise(createReadStream('image.jpg'), key)

// Save to auto generated sha1 key
await writeStreamPromise(createReadStream('image.jpg'), null, { algorithm: 'sha1' })

// Throw exception, if maxBytes is exceeded
await writeStreamPromise(createReadStream('image.jpg'), null, { algorithm: 'sha1', maxBytes: 10240 })

This will extend the IORedis client class with two additional functions:

readStream(key, options?): RedisRStream - Get a Readable stream from redis.

writeStream(key, options?): RedisWStream - Get a Writable stream from redis.

writeStreamPromise(rstream, key, options?): Promise<RedisWStream> - Promise version of writeStream(key)

Options for RedisRStream:

{ 
  highWaterMark, // maximum internal buffer size
}

Options for RedisWStream:

{ 
 highWaterMark, // maximum internal buffer size
 clientMulti,   // attach redis.multi in order to defer key rename
 algorithm,     // crypto algorithm for hashing
 maxBytes,      // maximum allowed bytes for writing
 ttl            // key expire time in seconds
}

Unit testing

yarn test

Credits

• https://github.com/jeffbski/redis-rstream
• https://github.com/jeffbski/redis-wstream
• https://github.com/4front/redis-streams

Copyright & License

Copyright (c) 2020 Jamify - Released under the MIT license.