@joshbetz/memcached
v1.4.0
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Memcached client for modern Node JS
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Memcached
There are three libraries exported from this package.
const { Memcached, Pool, HashPool } = require( '@joshbetz/memcached' );
API
The API for all three libraries is the same. It just depends what kind of connection and failover logic you need.
async ready()
Wait for the connection to be ready.
async flush()
Flush the Memcached data.
async set( key, value, ttl ): Boolean
SETs a given key and value for the specified TTL (or no TTL). Returns a Boolean to indicate whether the operation was successful.
async add( key, value, ttl ): Boolean
ADDs a given key and value for the specified TTL (or no TTL) if it doesn't already exist. Returns a Boolean to indicate whether the operation was successful.
async get( key ): string|Boolean
GETs a given key. Returns false
if it does not exist.
async del( key ): Boolean
DELETEs a given key.
async ping(): Boolean
Sends the version command. Returns true
if the expected response is returned.
async end()
Close the connection to Memcached.
Memcached Library
This is a simple Memcached library that connects to a Memcached server and execute commands.
Example
const opts = {
prefix: '',
socketTimeout: 100,
};
const memcached = new Memcached( 11211, 'localhost', opts );
await memcached.ready();
await memcached.set( 'key', 'value' );
const value = await memcached.get( 'key' );
await memcached.end();
Options
prefix
A prefix to apply to all keys. Default: (empty string)socketTimeout
The timeout to establish a connection. Default: 100.
Pool Library
This is a wrapper around our Memcached library that establishes a connection pool.
Example
const opts = {
// Pool options
max: 10,
min: 2,
acquireTimeoutMillis: 200,
destroyTimeoutMillis: 200,
maxWaitingClients: 2,
idleTimeoutMillis: 30000,
// Connection options
prefix: '',
socketTimeout: 100,
};
const memcached = new Pool( 11211, 'localhost', opts );
await memcached.set( 'key', 'value' );
const value = await memcached.get( 'key' );
await memcached.end();
Options
max
The maximum number of connections in the pool. Default: 10.min
The minimum number of connections in the pool. Default: 2.acquireTimeoutMillis
The maximum amount of time to wait to create a connection. Default: 200.destroyTimeoutMillis
The maximum amount of time to wait to destroy a connection. Default: 200.maxWaitingClients
The maximum number of queued requests allowed, additional acquire calls will be callback with an err in a future cycle of the event loop. Default: 2.idleTimeoutMillis
The minimum amount of time that an object may sit idle in the pool before it is eligible for eviction due to idle time. Default: 30000.prefix
A prefix to apply to all keys. Default: (empty string)socketTimeout
The timeout to establish a connection. Default: 100.
HashPool Library
This is a wrapper around our Pool library that establishes connection pools to each host and load balances queries across them. It includes automatic failover and reconnecting when hosts experience issues.
Example
const opts = {
retry: ( retries: number ): number => {
const exp = Math.pow( 2, retries ) * 250;
// exponential backoff up to 30 seconds
return Math.min( exp, 30000 );
},
// Pool options
max: 10,
min: 2,
acquireTimeoutMillis: 200,
destroyTimeoutMillis: 200,
maxWaitingClients: 2,
idleTimeoutMillis: 30000,
// Connection options
prefix: '',
socketTimeout: 100,
};
const memcached = new HashPool( [ 'localhost:11211', 'localhost:11311' ], opts );
await memcached.set( 'key', 'value' );
const value = await memcached.get( 'key' );
await memcached.end();
Options
retry
A function that takes the number of retries as a parameter and returns the time before the next retry in milliseconds.max
The maximum number of connections in the pool. Default: 10.min
The minimum number of connections in the pool. Default: 2.acquireTimeoutMillis
The maximum amount of time to wait to create a connection. Default: 200.destroyTimeoutMillis
The maximum amount of time to wait to destroy a connection. Default: 200.maxWaitingClients
The maximum number of queued requests allowed, additional acquire calls will be callback with an err in a future cycle of the event loop. Default: 2.idleTimeoutMillis
The minimum amount of time that an object may sit idle in the pool before it is eligible for eviction due to idle time. Default: 30000.prefix
A prefix to apply to all keys. Default: (empty string)socketTimeout
The timeout to establish a connection. Default: 100.