cache

Documentation

Overview

Package cache provides facilities to speed up access to the storage backend.

Index

• func NewCachedBlobStatter(cache distribution.BlobDescriptorService, ...) distribution.BlobDescriptorService
• func NewCachedBlobStatterWithMetrics(cache distribution.BlobDescriptorService, ...) distribution.BlobStatter
• func ValidateDescriptor(desc distribution.Descriptor) error
• type BlobDescriptorCacheProvider
• type Logger
• type Metrics
• type MetricsTracker

Functions

func NewCachedBlobStatter

func NewCachedBlobStatter(cache distribution.BlobDescriptorService, backend distribution.BlobDescriptorService) distribution.BlobDescriptorService

NewCachedBlobStatter creates a new statter which prefers a cache and falls back to a backend.

func NewCachedBlobStatterWithMetrics

func NewCachedBlobStatterWithMetrics(cache distribution.BlobDescriptorService, backend distribution.BlobDescriptorService, tracker MetricsTracker) distribution.BlobStatter

NewCachedBlobStatterWithMetrics creates a new statter which prefers a cache and falls back to a backend. Hits and misses will send to the tracker.

func ValidateDescriptor

func ValidateDescriptor(desc distribution.Descriptor) error

ValidateDescriptor provides a helper function to ensure that caches have common criteria for admitting descriptors.

Types

type BlobDescriptorCacheProvider

type BlobDescriptorCacheProvider interface {
	distribution.BlobDescriptorService

	RepositoryScoped(repo string) (distribution.BlobDescriptorService, error)
}

BlobDescriptorCacheProvider provides repository scoped BlobDescriptorService cache instances and a global descriptor cache.

type Logger

type Logger interface {
	Errorf(format string, args ...interface{})
}

Logger can be provided on the MetricsTracker to log errors.

Usually, this is just a proxy to dcontext.GetLogger.

type Metrics

type Metrics struct {
	Requests uint64
	Hits     uint64
	Misses   uint64
}

Metrics is used to hold metric counters related to the number of times a cache was hit or missed.

type MetricsTracker

type MetricsTracker interface {
	Hit()
	Miss()
	Metrics() Metrics
	Logger(context.Context) Logger
}

MetricsTracker represents a metric tracker which simply counts the number of hits and misses.