lambda-local-caching v0.0.3

Lambda-Local-Caching

Library for setting and retrieving local caching in AWS Lambda.

Overview

Anything declared outside the handler function (in global variable) is reused between invocations. The cached variable will live as long as the lambda container runs. As a result, there is no guarantee about the lifetime of the cached variable itself.

This library provides an expiry of each cached variable. The default caching expiry is 5 minutes.

Installation

npm i lambda-local-caching

How to Use

Cache Variable

import {cacheVariable, getCacheVariable} from 'lambda-local-caching'

const variableToBeCachedValue = 'abcd'
const key = 'variable-to-be-cached'
cacheVariable<string>(key, variableToBeCachedValue, 600)

Getting Cached Variable

import {cacheVariable, getCacheVariable} from 'lambda-local-caching'

const variableToBeCachedValue = 'abcd'
const key = 'variable-to-be-cached'
cacheVariable<string>(key, variableToBeCachedValue)

const result = getCacheVariable<string>(key)

console.log(result.isSuccessful) // true
console.log(result.value) //This will print out abcd

Unsuccessful retrieval

import {getCacheVariable} from 'lambda-local-caching'

const key = 'variable-to-be-cached'
const result = getCacheVariable<string>(key)

console.log(result.isSuccessful) // false
console.log(result.type) // FailureType.NotFound


cacheVariable<string>(key, 'some-value', 0) //expired
console.log(result.isSuccessful) // false
console.log(result.type) // FailureType.Expired

General Use Case (Getting & Setting the cached)

import {cacheVariable, getCacheVariable} from 'lambda-local-caching'

const key = 'variable-to-be-cached'

function getSomething(): string {
  const result = getCacheVariable<string>(key)
  if (!result.isSuccessful) {
    const value = getSomeOtherThingToBeCached()
    cacheVariable<string>(key, value)
    return value
  }
  return result.value
}