Memcached Spring Boot

Library that provides support for auto-configuration of Memcached cache in a Spring Boot application.

It provides implementation for the Spring Cache Abstraction, backed by the Xmemcached. Supports cache eviction per key, as well as clearing out of the entire cache region. Binaries are available from Maven Central.

Usage

To plug-in Memcached cache in your application follow the steps below:

Include library as a Gradle or Maven compile dependency:

Gradle

implementation('io.sixhours:memcached-spring-boot-starter:2.4.2')

Maven

<dependency>
    <groupId>io.sixhours</groupId>
    <artifactId>memcached-spring-boot-starter</artifactId>
    <version>2.4.2</version>
</dependency>

As the default implementation is backed by Xmemcached if there is a requirement to use Spymemcached (i.e. its forked AWS version) following configuation should be applied:

Gradle

implementation('io.sixhours:memcached-spring-boot-starter:2.4.2') {
  exclude group: 'com.googlecode.xmemcached', module: 'xmemcached'
}
implementation('com.amazonaws:elasticache-java-cluster-client:1.1.2')

Maven

<dependency>
    <groupId>io.sixhours</groupId>
    <artifactId>memcached-spring-boot-starter</artifactId>
    <version>2.4.2</version>
    <exclusions>
        <exclusion>
            <groupId>com.googlecode.xmemcached</groupId>
            <artifactId>xmemcached</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>com.amazonaws</groupId>
    <artifactId>elasticache-java-cluster-client</artifactId>
    <version>1.1.2</version>
</dependency>

Snapshot repository

If you want to use SNAPSHOT versions, add the snapshot-repo https://oss.sonatype.org/content/repositories/snapshots as shown in the example.

Configure Memcached key-value store in your properties file (application.yml).

Example

To manually connect to one or more cache servers (nodes), specify comma-separated list of hostname:port with the static provider:

 memcached.cache:
   servers: example1.com:11211,example2.com:11211
   provider: static
   # default expiration is '1d' ('86400' seconds) and custom ones for cache_name1 and cache_name2
   expiration: 1d
   expiration-per-cache:
     cache_name1: 1h
     cache_name2: 30h
   metrics-cache-names: cache_name1, cache_name2

To connect to a cluster with AWS Auto Discovery, specify cluster configuration endpoint in memcached.cache.servers property with the aws provider:

memcached.cache:
    servers: mycluster.example.com:11211
    provider: aws
    expiration: 86400 # default expiration set to '86400' seconds i.e. 1 day

To connect to a cluster within Google App Engine memcached service, it is sufficient to specify the configuration property for provider with value appengine:

memcached.cache:
    provider: appengine
    expiration: 86400 # default expiration set to '86400' seconds i.e. 1 day

Enable caching support by adding @EnableCaching annotation to one of your @Configuration classes.

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;

@SpringBootApplication
@EnableCaching
public class Application {

	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}
}

Now you can add caching to an operation of your service:

import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Component;

@Component
public class BookService {

    @Cacheable("books")
    public Book findByTitle(String title) {
        // ...
    }

}

For further details on using the Memcached cache in a Spring Boot application please look at the demo project.

Properties

Properties can be set in your application.yml file or as a command line properties. Below is the full list of supported properties:

# MEMCACHED CACHE
memcached.cache.servers: # Comma-separated list of hostname:port for memcached servers (default "localhost:11211")
memcached.cache.provider: # Memcached server provider (use one of following: "static", "aws" or "appengine"). Default provider is "static". Use "aws" for AWS node auto discovery, or "appengine" if running on Google Cloud Platform.
memcached.cache.expiration: # Default cache expiration if not configured per cache (default "0", meaning that cache will never expire). If unit not specified, seconds will be used.
memcached.cache.expiration-per-cache.cacheName: # To set expiration value for cache named "cacheName" {cache_name}:{number} e.g. "authors: 3600" or "authors: 1h". If unit not specified, seconds will be used.
memcached.cache.prefix: # Cache key prefix (default "memcached:spring-boot")
memcached.cache.protocol: # Memcached client protocol. Supports "text" and "binary" protocols (default is "text" protocol)
memcached.cache.operation-timeout: # Memcached client operation timeout (default "2500 milliseconds"). If unit not specified, milliseconds will be used.
memcached.cache.hash-strategy: # Memcached client hash strategy for distribution of data between servers. Supports "standard" (array based : "hash(key) mod server_count"), "libmemcached" (consistent hash), "ketama" (consistent hash), "php" (make easier to share data with PHP based clients), "election", "roundrobin", "random". Default is "standard".
memcached.cache.servers-refresh-interval: # Interval in milliseconds that refreshes the list of cache node hostnames and IP addresses for AWS ElastiCache. The default is 60000 milliseconds.
memcached.cache.metrics-cache-names: # Comma-separated list of cache names for which metrics will be collected.
memcached.cache.disabled-cache-names: # Comma-separated list of cache names for which caching will be disabled. The main purpose of this property is to disable caching for debugging purposes.

All of the values have sensible defaults and are bound to MemcachedCacheProperties class.

Duration properties such as expiration and expiration-per-cache by default are using unit of seconds if no unit is specified. For operation-timeout property unit of milliseconds is the default one.

E.g. to specify an expiration of 30 seconds, 30, PT30S (ISO-8601 format) and 30s are all equivalent. An operation-timeout of 500ms can be specified in any of the following form: 500, PT0.5S and 500ms.

Supported units are:

ns for nanoseconds
us for microseconds
ms for milliseconds
s for seconds
m for minutes
h for hours
d for days

Notice:

If different applications are sharing the same Memcached server, make sure to specify unique cache prefix for each application in order to avoid cache conflicts.

Build

In order to build the project you will have to have Java 1.8+ and Docker installed. To build the project invoke the following command:

./gradlew clean build

To install the modules in the local Maven repository:

./gradlew clean build publishToMavenLocal

License

Memcached Spring Boot is an Open Source software released under the Apache 2.0 license.

raycoarana/memcached-spring-boot

Memcached Spring Boot

Usage

Properties

Build

License