cache

Documentation

Overview

Package cache provides a generalized cache package that allows anything to be cached without having to know underlying details of where that cache is stored. All items are serialized into JSON and stored as strings. When retrieved, it's unmarshaled into the provided container. A single cache is maintained at the package level. The provided cacher should be thread-safe, as no locking occurs in this package.

Index

• Variables
• func DefaultHealthCheck() *health.Check
• func Delete(m metrics.Recorder, key string) error
• func FuzzDuration(d time.Duration, min, max int) time.Duration
• func Get(r metrics.Recorder, key string, container interface{}) error
• func HandlerWrapper(cacheDuration int, next http.Handler) http.HandlerFunc
• func HealthCheck(c Cacher) *health.Check
• func Initialize(cache Cacher, defaultDuration time.Duration)
• func Middleware(cacheDuration int, excludedPaths []string) func(http.Handler) http.Handler
• func Set(m metrics.Recorder, key string, value interface{}) error
• func SetWithDuration(m metrics.Recorder, key string, value interface{}, d time.Duration) error
• type CacheEvent
• type Cacher
  • func NewMemoryCache(defaultTTL time.Duration) Cacher
• type MemoryCache
  • func (c *MemoryCache) Delete(m metrics.Recorder, key string) error
  • func (c *MemoryCache) ForeverTTL() int
  • func (c *MemoryCache) Get(m metrics.Recorder, key string) (interface{}, error)
  • func (c *MemoryCache) Set(m metrics.Recorder, key string, value interface{}) error
  • func (c *MemoryCache) SetWithDuration(m metrics.Recorder, key string, value interface{}, d time.Duration) error
• type ResponseWriterTee
  • func (w *ResponseWriterTee) Header() http.Header
  • func (w *ResponseWriterTee) Write(b []byte) (int, error)
  • func (w *ResponseWriterTee) WriteHeader(statusCode int)

Variables

var (

	// ErrCacheNil is returned when caching falied due to the provided Cacher being nil
	ErrCacheNil = errors.New("cache is nil")

	// ErrCacheDisabled is returned when caching falied due to caching being disabled
	ErrCacheDisabled = errors.New("cache is disabled")

	// ErrDeserialize is returned when cache extraction failed due to deserialization errors.
	ErrDeserialize = errors.New("cached value could not be deserialized")

	// ErrNotFound is returned when no data was found
	ErrNotFound = errors.New("not found")

	// Enabled allows caching to be turned on and off. This is useful for turning cache off
	// via environment variables.
	Enabled = true
)

Functions

func DefaultHealthCheck

func DefaultHealthCheck() *health.Check

func Delete

func Delete(m metrics.Recorder, key string) error

Delete a value from cache.

func FuzzDuration

func FuzzDuration(d time.Duration, min, max int) time.Duration

Add a random amount of time to a time.Duration. Percent will be between min and max, inclusive.

func Get

func Get(r metrics.Recorder, key string, container interface{}) error

Get a value from cache.

func HandlerWrapper

func HandlerWrapper(cacheDuration int, next http.Handler) http.HandlerFunc

HandlerWrapper provices a cache-layer wrapper for a single API route.

func HealthCheck

func HealthCheck(c Cacher) *health.Check

func Initialize

func Initialize(cache Cacher, defaultDuration time.Duration)

Initialize must be called prior to use. Do this in main.

func Middleware

func Middleware(cacheDuration int, excludedPaths []string) func(http.Handler) http.Handler

Middleware provides a cache-layer middleware for caching the input/output for GET requests.

func Set

func Set(m metrics.Recorder, key string, value interface{}) error

Set a value in cache. Value MUST be serializeable by JSON. UnExported fields will be ignored!

func SetWithDuration

func SetWithDuration(m metrics.Recorder, key string, value interface{}, d time.Duration) error

SetWithDuration sets a value in cache. Value MUST be serializeable by JSON. UnExported fields will be ignored!

Types

type CacheEvent

type CacheEvent struct {
	Content    string      `json:"content"`
	StatusCode int         `json:"statusCode"`
	Headers    http.Header `json:"headers"`
}

type Cacher

type Cacher interface {
	Get(metrics.Recorder, string) (interface{}, error)
	Set(metrics.Recorder, string, interface{}) error
	SetWithDuration(metrics.Recorder, string, interface{}, time.Duration) error
	Delete(metrics.Recorder, string) error

	// ForeverTTL returns the specific value that represents the no-expire TTL value.
	ForeverTTL() int
}

Cacher provides an interface for working with a cache store.

func NewMemoryCache

func NewMemoryCache(defaultTTL time.Duration) Cacher

NewMemoryCache returns an in-memory Cacher

type MemoryCache

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

MemoryCache is an in-memory cache storage that satisfies the Cacher interface.

func (*MemoryCache) Delete

func (c *MemoryCache) Delete(m metrics.Recorder, key string) error

Delete removes a key from cache.

func (*MemoryCache) ForeverTTL

func (c *MemoryCache) ForeverTTL() int

ForeverTTL returns the go-cache value that represents the no-expire TTL value.

func (*MemoryCache) Get

func (c *MemoryCache) Get(m metrics.Recorder, key string) (interface{}, error)

Get a value from cache.

func (*MemoryCache) Set

func (c *MemoryCache) Set(m metrics.Recorder, key string, value interface{}) error

Set a value in cache.

func (*MemoryCache) SetWithDuration

func (c *MemoryCache) SetWithDuration(m metrics.Recorder, key string, value interface{}, d time.Duration) error

SetWithDuration sets a value in cache.

type ResponseWriterTee

type ResponseWriterTee struct {
	Buffer     bytes.Buffer
	StatusCode int
	// contains filtered or unexported fields
}

ResponseWriterTee captures input to an http.ResponseWriter

func (*ResponseWriterTee) Header

func (w *ResponseWriterTee) Header() http.Header

Header proxies http.ResponseWriter Header

func (*ResponseWriterTee) Write

func (w *ResponseWriterTee) Write(b []byte) (int, error)

Write proxies http.ResponseWriter Write

func (*ResponseWriterTee) WriteHeader

func (w *ResponseWriterTee) WriteHeader(statusCode int)

WriteHeader proxies http.ResponseWriter WriteHeader