High-Availability store

A better solution for entity management

How it works

Want to make your app faster and don't want to spend on extra infrastructure ?

HA-store is:

Smart caching for 'hot' information (in-memory or using redis-adapter)
Loads of features (request dedupping, batching, retrying and circuit-breaking)
Insightful stats and events
Lightweight and has zero dependencies

Installing

npm install ha-store

Usage

Data-Access layer

function getItems(ids, params) {
    // Some compute-heavy async function or external request to a DB / service
}

Store

const store = require('ha-store');
const itemStore = store({ getter: { method: getItems }});

Model

function getItemById(id, params) {
    itemStore.one(id, params)
        .then(item => /* The item you requested */);
}

Options

Name	Required	Default	Description
getter	true	-	The method to wrap, and how to interpret the returned data. Uses the format `<object>{ method: <function(ids, params)>, responseParser: <function(response, requestedIds)>`
uniqueOptions	false	`[]`	The list of parameters that, when passed, alter the results of the items requested. Ex: 'language', 'view', 'fields', 'country'. These will generate different combinaisons of cache keys.
cache	false	`{ base: 1000, step: 5, limit: 30000 }`	Caching options for the data
batch	false	`{ tick: 50, max: 100 }`	Batching options for the requests
retry	false	`{ base: 5, step: 3, limit: 5000 }`	Retry options for the requests
circuitBreaker	false	`{ base: 1000, steps: 0xffff, limit: 0xffffff }`	Circuit-breaker options, enabled by default and triggers after the retry limit

*All options are in (ms) *Scaling options are represented via and exponential curve with base and limit being the 2 edge values while steps is the number of events over that curve.

Monitoring and events

HA-store emits events to track cache hits, miss and outbound requests.

Event	Description
cacheHit	When the requested item is present in the microcache, or is already being fetched. Prevents another request from being created.
cacheMiss	When the requested item is not present in the microcache and is not currently being fetched. A new request will be made.
batch	When a batch of requests is about to be sent.
batchFailed	Indicates that the batch has failed. Retry policy will dictate if it should be re-attempted.
batchCancelled	Indicates that the batch has reached the allowed number of retries and is now abandonning.
batchSuccess	Indicates that the batch request was successful.
bumpCache	When a call for an item fully loaded in the microcache succeeds, it's ttl gets extended.
clearCache	When an item in the microcache has reached it's ttl and is now being evicted.
circuitBroken	When a batch call fails after the limit amount of retries, the circuit gets broken - all calls in the next ttl will automatically fail. It is assumed that there is a problem with the data-source.
circuitRestored	Circuit temporarily restored, a tentative to the data-source may be sent.
circuitRecovered	The tentative request was successful and the circuit it's assumed that the data-source has recovered.

Testing

npm test

Contribute

Please do! This is an open source project - if you see something that you want, open an issue or file a pull request.

I am always looking for more maintainers, as well.

Multimo/ha-store