cache

Documentation

Overview

Package cache implements a caching strategy for byte slices.

Index

• Variables
• type Cache
  • func ProvideCache(ctx context.Context, auto promauto.Factory, cfg *Config, logger *log.Logger) (*Cache, func(), error)
  • func (c *Cache) Get(key string, val interface{}) bool
  • func (c *Cache) Prune() (n int, err error)
  • func (c *Cache) Put(key string, val interface{})
• type Config
  • func (c *Config) Bind(flags *pflag.FlagSet)

Variables

var Set = wire.NewSet(
	ProvideCache,
)

Set is used by wire.

Types

type Cache

type Cache struct {
	// contains filtered or unexported fields
}

Cache implements a 3-level caching strategy.

func ProvideCache

func ProvideCache(
	ctx context.Context,
	auto promauto.Factory,
	cfg *Config,
	logger *log.Logger,
) (*Cache, func(), error)

ProvideCache is called by wire.

func (*Cache) Get

func (c *Cache) Get(key string, val interface{}) bool

Get retrieves a value from the cache, providing it to val, which must be a *[]byte, *string, or encoding.BinaryUnmarshaler.

func (*Cache) Prune

func (c *Cache) Prune() (n int, err error)

Prune removes cache files until they are below the configured threshold. Since atime is often disabled and we don't (yet) maintain any other statistics about file access, we select files randomly to delete.

func (*Cache) Put

func (c *Cache) Put(key string, val interface{})

Put stores a value into the Cache. The value must be a []byte, string, or an object which implements encoding.BinaryMarshaler.

type Config

type Config struct {
	MaxMem  int    // Maximum in-memory cache size, in MB.
	MaxDisk int    // Maximum on-disk cache size, in MB.
	Path    string // The location of the disk cache.

	// OnAdd is an optional callback that will be notified when new
	// data is added to the cache.
	OnAdd func(key string, data []byte)

	// OnMiss provides an escape-hatch for retrieving cached data from
	// other stores. Any non-nil error may be returned to indicate a
	// cache miss.
	OnMiss func(key string) ([]byte, error)
}

Config provides knobs for the cache.

func (*Config) Bind

func (c *Config) Bind(flags *pflag.FlagSet)

Bind attaches the configuration to the pflag.FlagSet.