Documentation
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Overview ¶
Package cache implements an caches for objects.
Index ¶
Constants ¶
This section is empty.
Variables ¶
Functions ¶
This section is empty.
Types ¶
type Cacher ¶
type Cacher interface {
// Closer closes the cache, cleaning up any stale entries. A closed cache is
// no longer valid and attempts to call methods should return an error or
// (less preferred) panic.
io.Closer
// Fetch retrieves the named item from the cache. If the item does not exist,
// it calls FetchFunc to create the item. If FetchFunc returns an error, the
// error is bubbled up the stack and no value is cached. If FetchFunc
// succeeds, the value is cached for the provided TTL.
Fetch(context.Context, *Key, interface{}, time.Duration, FetchFunc) error
// Read gets an item from the cache and reads it into the provided interface.
// If it does not exist, it returns ErrNotFound.
Read(context.Context, *Key, interface{}) error
// Write adds an item to the cache, overwriting if it already exists, caching
// for TTL. It returns any errors that occur on writing.
Write(context.Context, *Key, interface{}, time.Duration) error
// Delete removes an item from the cache, returning any errors that occur.
Delete(context.Context, *Key) error
// DeletePrefix removes all items from the cache that begin with the given
// value.
DeletePrefix(context.Context, string) error
}
Cacher is an interface that defines caching.
func NewInMemory ¶
func NewInMemory(i *InMemoryConfig) (Cacher, error)
NewInMemory creates a new in-memory cache.
func NewRedis ¶
func NewRedis(i *RedisConfig) (Cacher, error)
NewRedis creates a new in-memory cache.
type CacherType ¶
type CacherType string
CacherType represents a type of cacher.
const ( TypeNoop CacherType = "NOOP" TypeInMemory CacherType = "IN_MEMORY" TypeRedis CacherType = "REDIS" )
type Config ¶
type Config struct {
Type CacherType `env:"CACHE_TYPE, default=IN_MEMORY"`
// HMACKey is the hash key to use when for keys in the cacher.
HMACKey envconfig.Base64Bytes `env:"CACHE_HMAC_KEY, required"`
// Redis configuration
Redis redis.Config `env:", prefix=CACHE_"`
}
Config represents configuration for a cacher.
type FetchFunc ¶
type FetchFunc func() (interface{}, error)
FetchFunc is a function used to Fetch in a cacher.
type InMemoryConfig ¶
type Key ¶ added in v0.12.1
Key is a cache key. It has an optional Namespace. Any KeyFunc are applied to the Key, but not the Namespace.
type KeyFunc ¶
KeyFunc is a function that mutates the provided cache key before storing it in Redis. This can be used to hash or HMAC values to prevent their plaintext from appearing in Redis. A good example might be an API key lookup that you HMAC before passing along.
The KeyFunc can also be used to add a prefix or namespace to keys in multi-tenant systems.
func HMACKeyFunc ¶ added in v0.8.0
HMACKeyFunc returns a KeyFunc that HMACs the provided key before passing it to the cacher for storage.
func HashKeyFunc ¶
HashKeyFunc returns a KeyFunc that hashes the provided key before passing it to the cacher for storage.
func MultiKeyFunc ¶
MultiKeyFunc returns a KeyFunc that calls the provided KeyFuncs in order, with the previous value passed to the next.
type RedisConfig ¶
type RedisConfig struct {
// Address is the redis address and port. The default value is 127.0.0.1:6379.
Address string
// Username and Password are used for authentication.
Username, Password string
// IdleTimeout, MaxIdle, and MaxActive control connection handling.
IdleTimeout time.Duration
MaxIdle int
MaxActive int
// KeyFunc is the key function.
KeyFunc KeyFunc
// WaitTimeout is the maximum amount of time to wait for a connection to
// become available.
WaitTimeout time.Duration
}
Source Files