(-_-)ゞ゛ Omnesiac

Overview

A library implementing the marriage of two abstractions:

• Mutual Exclusion
• Memoization w/Time-to-Live

Concretely, this library was built to service two use-cases:

• I need to perform some asynchronous work, throttled per unique key, and all subsequent calls using that key will block and await the result of that asynchronous work.
• I need to perform some asynchronous work, throttled per unique key, and all subsequent calls using that key will continue without knowing the result of that asynchronous work.

tldr; a mutex-based throttling mechanism in blocking and non-blocking flavors.

Installation

Tested with >= Node.js 8.x

yarn add omnesiac

Usage

const Omnesiac = require('omnesiac');

async function doPeriodicAsynchronousWork(arg1, arg2) {
  /* 
    ...Do the deed...
  */
}

/*
 Memoize the results of this function for 30 seconds, and block subsequent calls while the asynchronous work is in-flight
*/
const throttledFn = Omnesiac(doPeriodicAsynchronousWork, { ttl: 30000, blocking: true });

const param1 = 'firstArgToTargetFunction';
const param2 = 'secondArgToTargetFunction';
const throttleKey = 'anyStringPerhapsAUserId';

/*
  The first call will execute the function. Subsequent calls using the same throttleKey will wait
  for the first call to finish and then resolve with the result of the first call for the next 30 seconds,
  whereupon, the next call will resume blocking until it has resolved, and on...
*/
const results = await throttledFn(throttleKey, param1, param2);

TODO

• Better Documentation
  • Behavior
    • { ttl: 0 } = Never expire / cache forever
    • Resolution order of blocked calls not guaranteed
  • Real-world Use Cases
    • [Non-Blocking] Sample data collection, where approximate precision is good-enough
    • [Blocking] Cacheing burstable requests against shared resources
• Timeouts on resolution of decorated function calls?
  • Maybe better to leave the onus on the function prior to Omnesiac decoration
  • Might make sense in the blocking scenario
• Many more tests
  • Ensure proper scoping / garbage-collection aspects

Contributing

1. Fork repo
2. Add / modify tests
3. Add / modify implementation*
4. Open PR

* (Optional, but strongly encouraged) Link to your development soundtrack appending this README.md

License

MIT License

Copyright (c) 2020 Ombud

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Soundtrack

If you contribute to this library you are strongly encouraged to append your development soundtrack as a link to this README.md. One link per-PR, please, and it should be publicly, freely accessible (Youtube is a good option).