MemcachedCache

Distributed cache that stores values in Memcached’s caching service.

Description

The MemcachedCache class allows you to create distributed cache that stores values in Memcached’s caching service.

Important points

  • The current implementation does not support authentication.

Configuration parameters

  • connection(s):
    • discovery_key: (optional) key to retrieve the connection from IDiscovery
    • host: host name or IP address
    • port: port number
    • uri: resource URI or connection string with all parameters in it
  • options:
    • max_size: maximum number of values stored in this cache (default: 1000)
    • max_key_size: maximum key length (default: 250)
    • max_expiration: maximum expiration duration in milliseconds (default: 2592000)
    • max_value: maximum value length (default: 1048576)
    • pool_size: pool size (default: 5)
    • reconnect: reconnection timeout in milliseconds (default: 10 sec)
    • retries: number of retries (default: 3)
    • timeout: default caching timeout in milliseconds (default: 1 minute)
    • failures: number of failures before stop retrying (default: 5)
    • retry: retry timeout in milliseconds (default: 30 sec)
    • idle: idle timeout before disconnecting in milliseconds (default: 5 sec)

References

  • *:discovery:*:*:1.0 - (optional) IDiscovery services to resolve connection

Constructors

NewMemcachedCache

Creates a new instance of this lock.

NewMemcachedCacheT any *MemcachedCache[T]

Methods

Close

Closes a component and frees used resources.

(c *MemcachedCache[T]) Close(ctx context.Context, context IContext) error

  • ctx: context.Context - operation context.
  • context: IContext - (optional) a context to trace execution through a call chain.
  • returns: error - error or nil if no errors occurred

Contains

Contains check is value stores

Contains(ctx context.Context, context IContext, key string) bool

  • ctx: context.Context - operation context.
  • context: IContext - (optional) a context to trace execution through a call chain.
  • key: string - a unique value key.

Configure

Configures a component by passing its configuration parameters.

(c *MemcachedCache[T]) Configure(ctx context.Context, config *ConfigParams)

  • ctx: context.Context - operation context.
  • config: *ConfigParams - configuration parameters to be set.

IsOpen

Checks if the component is open.

(c *MemcachedCache[T]) IsOpen() bool

  • returns: bool - true if the component is open and false otherwise.

Open

Opens the component.

(c *MemcachedCache[T]) Open(ctx context.Context, context IContext) error

  • ctx: context.Context - operation context.
  • context: IContext - (optional) transaction id used to trace execution through the call chain.
  • returns: error - error or nil if no errors occurred

Remove

Removes a value from the cache by its key.

(c *MemcachedCache[T]) Remove(ctx context.Context, context IContext, key string) error

  • ctx: context.Context - operation context.
  • context: IContext - (optional) a context to trace execution through a call chain.
  • key: string - unique value key.
  • returns: error - error or nil if no errors occurred

Retrieve

Retrieves a cached value from the cache using its key. If the value is missing in the cache or expired, it returns nil.

(c *MemcachedCache[T]) Retrieve(ctx context.Context, context IContext, key string) (value T, err error)

  • ctx: context.Context - operation context.
  • context: IContext - (optional) a context to trace execution through a call chain.
  • key: string - unique value key.
  • return: (value T, err error) - cached value or nil if nothing was found.

SetReferences

Sets references to dependent components.

(c *MemcachedCache[T]) SetReferences(ctx context.Context, references IReferences)

  • ctx: context.Context - operation context.
  • references: IReferences - references to locate the component’s dependencies.

Store

Stores a value in the cache with an expiration time.

(c *MemcachedCache[T]) Store(ctx context.Context, context IContext, key string, value T, timeout int64) (result T, err error)

  • ctx: context.Context - operation context.
  • context: IContext - (optional) a context to trace execution through a call chain.
  • key: string - unique value key.
  • value: T - value to store.
  • timeout: int64 - expiration timeout in milliseconds.
  • returns: (result T, err error) - stored value

Examples

ctx := context.Background()

cache := NewMemcachedCache[string]()
cache.Configure(ctx, cconf.NewConfigParamsFromTuples(
  "host", "localhost",
  "port", 11211,
))
err := cache.Open(ctx, "123")
  ...
ret, err := cache.Store(ctx, "123", "key1", []byte("ABC"))
if err != nil {
	...
}
res, err := cache.Retrive(ctx, "123", "key1")
value, _ := res.([]byte)
fmt.Println(string(value))  // Result: "ABC"