drotto
v0.3.5
Published
NodeJS Process Pool
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drotto
Drotto ("Dr Otto") is a lean, NodeJS process pool, allowing for both single and multi function parallel processing.
Why drotto?
NodeJS is single threaded. While I/O tasks can be parallelized over the OS with it’s asynchronous architecture, CPU bound workloads block the event loop, leading to potentially disastrous performance. To avoid this, NodeJS offers libraries to parallelize CPU bound workloads over CPU cores via new processes. Drotto is a lightweight abstraction for managing creation, delegation, and deletion of parallelized NodeJS worker processes.
Installation
$ npm i --save drotto
Examples
SEE tutorials for more code samples
To parallelize a single function:
(async () => {
// obtain an Executor instance
const executor = Executor.fixedPool(os.cpus().length - 1);
// invoke cpu bound function with param
const p = executor.invoke(max => {
for (let i = 0; i < max; i++) { }
return max;
}, [500000000]);
// handle promise
p.then(result => {
console.log(`Finished ${result} iterations...`);
executor.shutdown(); // stop processes
}).catch(e => {
console.log('Exception', e);
executor.shutdown(); // stop processes
});
console.log('asynchronous execution...');
})();
To parallelize multiple functions:
(async () => {
// obtain an Executor instance
const executor = Executor.fixedPool(os.cpus().length - 1);
// cpu bound function
const fn = (max) => {
for (let i = 0; i < max; i++) { }
return max;
};
try {
console.log('Running four functions...');
const promises = executor.invokeAll([fn, fn, fn, fn], [[40000000], [20000000], [60000000], [30000000]]);
const results = await Promise.all(promises);
console.log('Finished all iterations...', results);
} catch (e) {
console.log('Exception Message', e.message);
console.log('Exception Stack Trace', e.stack);
}
executor.shutdown();
})();
Limitations
Currently the CPU bound functions are not able to run functions or functions attached to objects that are injected as parameters, nor are they able to require additional modules from inside of the functions.