cache: gitoa.ru/go-4devs/cache Index | Examples | Files | Directories

package cache

import "gitoa.ru/go-4devs/cache"

Index

Examples

Package Files

cache.go error.go item.go operation.go provider.go type_assert.go

Constants

❖
const (
    OperationGet    = "get"
    OperationSet    = "set"
    OperationDelete = "delete"
)

available operation.

Variables

❖
var (
    ErrCacheMiss          = errors.New("cache miss")
    ErrCacheExpired       = errors.New("cache expired")
    ErrSourceNotValid     = errors.New("source is not valid")
    ErrKeyNotValid        = errors.New("key is not valid")
    ErrTargetNil          = errors.New("target is nil")
    ErrOperationNotAllwed = errors.New("operation not allowed")
)

Cached errors.

func TypeAssert Uses

❖
func TypeAssert(source, target interface{}) (err error)

TypeAssert assert source to target.

type Cache Uses

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

Cache base cache.

Example (ClearByContext)

Code: 

type ctxKey int

var (
    requestID       ctxKey = 1
    cached, cached2 string
)

ctx, cancel := context.WithCancel(context.WithValue(context.Background(), requestID, "unique ctx key"))
ctx2 := context.WithValue(context.Background(), requestID, "unique ctx key2")
c := cache.New(provider(),
    mw.WithClearByContext(requestID),
    cache.WithDataOption(cache.WithNamespace("clear_by_ctx", "")),
)

fmt.Printf("err: %v\n", c.Set(ctx, 1, "some ctx loaded data", cache.WithTTL(time.Hour)))
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, 1, &cached), cached)
cancel()
time.Sleep(time.Millisecond)
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx2, 1, &cached2), cached2)

Output:

err: <nil>
err: <nil>, value: 'some ctx loaded data'
err: cache miss: map, value: ''
Example (ClearByTTL)

Code: 

ctx := context.Background()
c := cache.New(provider(),
    mw.WithClearByTTL(),
    cache.WithDataOption(cache.WithNamespace("clear_by_ttl", "")),
)

var cached, cached2 string

fmt.Printf("err: %v\n", c.Set(ctx, 1, "some ttl loaded data", cache.WithTTL(time.Microsecond*200)))
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, 1, &cached), cached)
time.Sleep(time.Second)
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, 1, &cached2), cached2)

Output:

err: <nil>
err: <nil>, value: 'some ttl loaded data'
err: cache miss: map, value: ''
Example (Encoding)

Code: 

ctx := context.Background()
c := cache.New(memory.NewEncoding(), cache.WithDataOption(cache.WithMarshal(gob.Unmarshal, gob.Marshal)))

var cached string

fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "not found key", &cached), cached)
fmt.Printf("err: %v\n", c.Set(ctx, "key", "some value"))
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "key", &cached), cached)

Output:

err: cache miss: encoding, value: ''
err: <nil>
err: <nil>, value: 'some value'
Example (Lru)

Code: 

ctx := context.Background()
client, _ := glru.New(10)

c := cache.New(lru.New(client), cache.WithDataOption(cache.WithTTL(time.Hour)))

var cached string

fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "not found lru key", &cached), cached)
fmt.Printf("err: %v\n", c.Set(ctx, "key", "some lru value"))
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "key", &cached), cached)
fmt.Printf("deleted err: %v\n", c.Delete(ctx, "key"))

Output:

err: cache miss: lru, value: ''
err: <nil>
err: <nil>, value: 'some lru value'
deleted err: <nil>
Example (Map)

Code: 

ctx := context.Background()
c := cache.New(memory.NewMap())

var cached string

fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "not found key", &cached), cached)
fmt.Printf("err: %v\n", c.Set(ctx, "key", "some value"))
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "key", &cached), cached)

Output:

err: cache miss: map, value: ''
err: <nil>
err: <nil>, value: 'some value'
Example (Memacache)

Code: 

ctx := context.Background()
c := cache.New(memcache.New(test.MemcacheClient()), cache.WithDataOption(cache.WithNamespace("memcache", ":")))

var cached string

fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "not found memcached key", &cached), cached)
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "not:found:memcached:key", &cached), cached)
fmt.Printf("err: %v\n", c.Set(ctx, "key", "some mamcache value"))
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "key", &cached), cached)

Output:

err: key is not valid: memcache, value: ''
err: cache miss: memcache, value: ''
err: <nil>
err: <nil>, value: 'some mamcache value'
Example (Redis)

Code: 

ctx := context.Background()
c := cache.New(redis.New(test.RedisClient()))

var cached string

fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "not found redis key", &cached), cached)
fmt.Printf("err: %v\n", c.Set(ctx, "key", "some redis value", cache.WithNamespace("redis", ":")))
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, "redis:key", &cached), cached)

Output:

err: cache miss: redis pool, value: ''
err: <nil>
err: <nil>, value: 'some redis value'
Example (WithFallback)

Code: 

ctx := context.Background()
c := cache.New(provider(), mw.WithFallback(
    func(ctx context.Context, key, value interface{}) error {
        fmt.Printf("loaded key: %#v\n", key)

        return cache.TypeAssert("some loaded data", value)
    },
    func(i *cache.Item, e error) bool {
        return e != nil
    },
))

var cached, cached2 string

fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, 1, &cached), cached)
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, 1, &cached2), cached2)

Output:

loaded key: 1
err: <nil>, value: 'some loaded data'
err: <nil>, value: 'some loaded data'
Example (WithMetrics)

Code: 

ctx := context.Background()
cacheLabel := "cache_label"
c := cache.New(provider(),
    mw.WithMetrics(prometheus.Metrics{}, mw.LabelName(cacheLabel)),
    cache.WithDataOption(cache.WithNamespace("metrics", ":")),
)

var cached, cached2 string

fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, 1, &cached), cached)
fmt.Printf("err: %v\n", c.Set(ctx, 1, "cached"))
fmt.Printf("err: %v, value: '%v'\n", c.Get(ctx, 1, &cached2), cached2)

mfs, _ := prom.DefaultGatherer.Gather()
for _, mf := range mfs {
    for _, metric := range mf.GetMetric() {
        label := metric.GetLabel()
        if len(label) > 0 && metric.Counter != nil {
            fmt.Printf("name:%s, label:%s, value: %.0f\n", *mf.Name, *label[0].Value, mf.GetMetric()[0].Counter.GetValue())
        }
    }
}

Output:

err: cache miss: map, value: ''
err: <nil>
err: <nil>, value: 'cached'
name:cache_hit_total, label:cache_label, value: 1
name:cache_miss_total, label:cache_label, value: 1
Example (WithNamespace)

Code: 

ctx := context.Background()
c := cache.New(provider(), cache.WithDataOption(
    cache.WithNamespace("prefix", ":"),
    cache.WithTTL(time.Hour),
))

var cached, cached2 string

fmt.Printf("prefix  err: %v, value: '%v'\n", c.Get(ctx, "key", &cached), cached)
fmt.Printf("prefix  err: %v\n", c.Set(ctx, "key", "some value", cache.WithTTL(time.Minute)))
fmt.Printf("prefix2 err: %v\n", c.Set(ctx, "key", "some value2", cache.WithNamespace("prefix2", ":")))
fmt.Printf("prefix  err: %v, value: '%v'\n", c.Get(ctx, "key", &cached), cached)
fmt.Printf("prefix2 err: %v, value: '%v'\n", c.Get(ctx, "key", &cached2, cache.WithNamespace("prefix2", ":")), cached2)

Output:

prefix  err: cache miss: map, value: ''
prefix  err: <nil>
prefix2 err: <nil>
prefix  err: <nil>, value: 'some value'
prefix2 err: <nil>, value: 'some value2'

func New Uses

❖
func New(prov Provider, opts ...Configure) *Cache

New creates new cache by provider.

func (*Cache) Delete Uses

❖
func (c *Cache) Delete(ctx context.Context, key interface{}, opts ...Option) error

Delete handles middlewares and delete value by key and options.

func (*Cache) Execute Uses

❖
func (c *Cache) Execute(ctx context.Context, operation string, key, value interface{}, opts ...Option) error

func (*Cache) Get Uses

❖
func (c *Cache) Get(ctx context.Context, key, value interface{}, opts ...Option) error

Get handles middlewares and gets value by key and options.

func (*Cache) Item Uses

❖
func (c *Cache) Item(key, value interface{}, opts ...Option) *Item

func (*Cache) Set Uses

❖
func (c *Cache) Set(ctx context.Context, key, value interface{}, opts ...Option) error

Set handles middlewares and sets value by key and options.

func (*Cache) With Uses

❖
func (c *Cache) With(opts ...Configure) *Cache

type Configure Uses

❖
type Configure func(*Cache)

Configure configure cache.

func WithDataOption Uses

❖
func WithDataOption(do ...Option) Configure

WithDataOption sets cache default data options.

func WithDefaultNamespace Uses

❖
func WithDefaultNamespace(ns, separator string) Configure

WithDefaultNamespace sets cache default namespace.

func WithDefaultTTL Uses

❖
func WithDefaultTTL(ttl time.Duration) Configure

WithDefaultTTL sets cache default ttl.

func WithHandleDelete Uses

❖
func WithHandleDelete(m ...Handle) Configure

WithHandleDelete add a handler for the delete operation.

func WithHandleGet Uses

❖
func WithHandleGet(m ...Handle) Configure

WithHandleGet add a handler for the get operation.

func WithHandleOperation Uses

❖
func WithHandleOperation(op string, m ...Handle) Configure

WithHandleOperation add a handler for the operation.

func WithHandleSet Uses

❖
func WithHandleSet(m ...Handle) Configure

WithHandleSet add a handler for the set operation.

func WithMiddleware Uses

❖
func WithMiddleware(mw ...Handle) Configure

WithMiddleware sets middleware to provider.

type ErrorTarget Uses

❖
type ErrorTarget struct {
    // contains filtered or unexported fields
}

ErrorTarget errs target is not a settable.

func NewErrorTarget Uses

❖
func NewErrorTarget(target interface{}) ErrorTarget

NewErrorTarget creates new target error.

func (ErrorTarget) Error Uses

❖
func (e ErrorTarget) Error() string

ErrorTarget errors.

type Handle Uses

❖
type Handle func(ctx context.Context, operation string, item *Item, next Provider) error

Handle middleware before/after provider.

func ChainHandle Uses

❖
func ChainHandle(handle ...Handle) Handle

ChainHandle chain handle middleware.

type Item Uses

❖
type Item struct {
    Key   Key
    Value interface{}
    TTL   time.Duration
    // contains filtered or unexported fields
}

Item to pass to the provider.

func NewItem Uses

❖
func NewItem(key, value interface{}, opts ...Option) *Item

NewItem creates and configure new item.

func (*Item) Expired Uses

❖
func (i *Item) Expired() time.Time

Expired get the time when the ttl is outdated.

func (*Item) IsExpired Uses

❖
func (i *Item) IsExpired() bool

IsExpired checks expired item.

func (*Item) Marshal Uses

❖
func (i *Item) Marshal() ([]byte, error)

func (*Item) Options Uses

❖
func (i *Item) Options() []Option

Options gets item options.

func (*Item) TTLInSecond Uses

❖
func (i *Item) TTLInSecond(in int64)

TTLInSecond to set the ttl in seconds.

func (*Item) Unmarshal Uses

❖
func (i *Item) Unmarshal(data []byte) error

func (*Item) With Uses

❖
func (i *Item) With(key, val interface{}, opts ...Option) *Item

type Key Uses

❖
type Key struct {
    Key       interface{}
    Prefix    string
    Separator string
}

Key with prefix and separator.

func (Key) String Uses

❖
func (k Key) String() string

String returns a formatted key.

func (Key) Value Uses

❖
func (k Key) Value() interface{}

type Option Uses

❖
type Option func(*Item)

Option ffor the configuration item.

func WithMarshal Uses

❖
func WithMarshal(unmarshal encoding.Unmarshal, marshal encoding.Marshal) Option

WithMarshal sets marshal and unmarshal.

func WithNamespace Uses

❖
func WithNamespace(prefix, sep string) Option

WithNamespace sets prefix and separator.

func WithTTL Uses

❖
func WithTTL(ttl time.Duration) Option

WithTTL sets ttl.

type Provider Uses

❖
type Provider func(ctx context.Context, operation string, item *Item) error

Provider for different types of cache, in memory, lru, redis.

func OperationProvider Uses

❖
func OperationProvider(prov map[string]func(ctx context.Context, item *Item) error) Provider

OperationProvider creating a provider based on available operations.

Directories

PathSynopsis
item
mw
mw/prometheus
provider/lru
provider/memcache
provider/memory
provider/pebble
provider/redis
provider/ristretto
test

Package cache imports 8 packages (graph) and is imported by 9 packages. Updated 2020-09-30. Refresh now. Tools for package owners.