stats

Documentation

Overview

Package stats defines a stats provider service, wrapping a cache & stats component calculation

Index

• Variables
• type Cache
  • func NewLocalCache(rootDir string, maxSize int64) (Cache, error)
• type Props
• type Service
  • func New(cache Cache) *Service
  • func (s *Service) Stats(ctx context.Context, ds *dataset.Dataset) (*dataset.Stats, error)

Variables

var (
	// ErrCacheMiss indicates a requested path isn't in the cache
	ErrCacheMiss = fmt.Errorf("stats: cache miss")
	// ErrNoCache indicates there is no cache
	ErrNoCache = fmt.Errorf("stats: no cache")
	// ErrCacheCorrupt indicates a faulty stats cache
	ErrCacheCorrupt = fmt.Errorf("stats: cache is corrupt")
)

Types

type Cache

type Cache interface {
	// placing a stats object in the Cache will expire all caches with a lower
	// modTime, use a modTime of zero when no modTime is known
	PutStats(ctx context.Context, key string, sa *dataset.Stats) error
	// GetStats the stats component for a given key
	GetStats(ctx context.Context, key string) (sa *dataset.Stats, err error)
}

Cache is a store of stats components Consumers of a cache must not rely on the cache for persistence Implementations are expected to maintain their own size bounding semantics internally Cache implementations must be safe for concurrent use, and must be nil-callable

func NewLocalCache

func NewLocalCache(rootDir string, maxSize int64) (Cache, error)

NewLocalCache creates a cache in a local directory. LocalCache is sensitive to added keys that match the qfs.PathKind of "local". When a stats component is added with a local filepath as it's key, LocalCache will record the status of that file, and return ErrCacheMiss if that filepath is altered on retrieval

type Props

type Props = didmod.Props

Props is an alias of

type Service

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

Service can generate an array of statistical info for a dataset

func New

func New(cache Cache) *Service

New allocates a Stats service

func (*Service) Stats

func (s *Service) Stats(ctx context.Context, ds *dataset.Dataset) (*dataset.Stats, error)

Stats gets the stats component for a dataset, possibly calculating by consuming the open dataset body file