memcache

package
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 Go to latest Published: Jan 26, 2024 License: Apache-2.0 Imports: 12 Imported by: 0

Documentation

Overview

Package memcache provides a client for the memcached cache server.

Index

Constants

View Source 
const (
	// DefaultTimeout is the default socket read/write timeout.
	DefaultTimeout     = 100 * time.Millisecond
	DefaultAuthTimeout = 300 * time.Millisecond

	// DefaultMaxIdleConns is the default maximum number of idle connections
	// kept for any single address.
	DefaultMaxIdleConns = 2
)

Variables

View Source 
var (
	// ErrCacheMiss means that a Get failed because the item wasn't present.
	ErrCacheMiss = types.ErrCacheMiss

	// ErrCASConflict means that a CompareAndSwap call failed due to the
	// cached value being modified between the Get and the CompareAndSwap.
	// If the cached value was simply evicted rather than replaced,
	// ErrNotStored will be returned instead.
	ErrCASConflict = types.ErrCASConflict

	// ErrNotStored means that a conditional write operation (i.e. Add or
	// CompareAndSwap) failed because the condition was not satisfied.
	ErrNotStored = types.ErrNotStored

	// ErrServer means that a server error occurred.
	ErrServerError = types.ErrServerError

	// ErrNoStats means that no statistics were available.
	ErrNoStats = types.ErrNoStats

	// ErrMalformedKey is returned when an invalid key is used.
	// Keys must be at maximum 250 bytes long and not
	// contain whitespace or control characters.
	ErrMalformedKey = types.ErrMalformedKey

	// ErrNoServers is returned when no servers are configured or available.
	ErrNoServers = types.ErrNoServers

	ErrValueTooLarge  = types.ErrValueTooLarge
	ErrInvalidArgs    = types.ErrInvalidArgs
	ErrValueNotStored = types.ErrValueNotStored
	ErrNonNumeric     = types.ErrNonNumeric
	ErrAuthRequired   = types.ErrAuthRequired
	ErrAuthContinue   = types.ErrAuthContinue
	ErrUnknownCommand = types.ErrUnknownCommand
	ErrOutOfMemory    = types.ErrOutOfMemory
	ErrUnknownError   = types.ErrUnknownError
)

Functions

This section is empty.

Types

type Client 

type Client struct {
	// Timeout specifies the socket read/write timeout.
	// If zero, DefaultTimeout is used.
	Timeout     time.Duration
	AuthTimeout time.Duration

	// MaxIdleConns specifies the maximum number of idle connections that will
	// be maintained per address. If less than one, DefaultMaxIdleConns will be
	// used.
	//
	// Consider your expected traffic rates and latency carefully. This should
	// be set to a number higher than your peak parallel requests.
	MaxIdleConns int

	Username, Password string
	// contains filtered or unexported fields
}

Client is a memcache client. It is safe for unlocked use by multiple concurrent goroutines.

func New 

func New(server ...string) *Client

New returns a memcache client using the provided server(s) with equal weight. If a server is listed multiple times, it gets a proportional amount of weight.

func NewBinary 

func NewBinary(server ...string) *Client

func NewFromSelector 

func NewFromSelector(ss ServerSelector) *Client

NewFromSelector returns a new Client using the provided ServerSelector.

func NewFromSelectorBinary 

func NewFromSelectorBinary(ss ServerSelector) *Client

func (*Client) Add 

func (c *Client) Add(item *Item) error

Add writes the given item, if no value already exists for its key. ErrNotStored is returned if that condition is not met.

func (*Client) CompareAndSwap 

func (c *Client) CompareAndSwap(item *Item) error

CompareAndSwap writes the given item that was previously returned by Get, if the value was neither modified or evicted between the Get and the CompareAndSwap calls. The item's Key should not change between calls but all other item fields may differ. ErrCASConflict is returned if the value was modified in between the calls. ErrNotStored is returned if the value was evicted in between the calls.

func (*Client) Decrement 

func (c *Client) Decrement(key string, delta uint64) (newValue uint64, err error)

Decrement atomically decrements key by delta. The return value is the new value after being decremented or an error. If the value didn't exist in memcached the error is ErrCacheMiss. The value in memcached must be an decimal number, or an error will be returned. On underflow, the new value is capped at zero and does not wrap around.

func (*Client) Delete 

func (c *Client) Delete(key string) error

Delete deletes the item with the provided key. The error ErrCacheMiss is returned if the item didn't already exist in the cache.

func (*Client) DeleteAll 

func (c *Client) DeleteAll() error

DeleteAll deletes all items in the cache.

func (*Client) FlushAll 

func (c *Client) FlushAll() error

func (*Client) Get 

func (c *Client) Get(key string) (item *Item, err error)

Get gets the item for the given key. ErrCacheMiss is returned for a memcache cache miss. The key must be at most 250 bytes in length.

func (*Client) GetMulti 

func (c *Client) GetMulti(keys []string) (map[string]*Item, error)

GetMulti is a batch version of Get. The returned map from keys to items may have fewer elements than the input slice, due to memcache cache misses. Each key must be at most 250 bytes in length. If no error is returned, the returned map will also be non-nil.

func (*Client) GetMultiWithBatches 

func (c *Client) GetMultiWithBatches(keys []string) (map[string]*Item, error)

func (*Client) Increment 

func (c *Client) Increment(key string, delta uint64) (newValue uint64, err error)

Increment atomically increments key by delta. The return value is the new value after being incremented or an error. If the value didn't exist in memcached the error is ErrCacheMiss. The value in memcached must be an decimal number, or an error will be returned. On 64-bit overflow, the new value wraps around.

func (*Client) Ping 

func (c *Client) Ping() error

Ping checks all instances if they are alive. Returns error if any of them is down.

func (*Client) ProtoType 

func (c *Client) ProtoType() string

func (*Client) RegisterOnCloseConnCallback 

func (c *Client) RegisterOnCloseConnCallback(fn func())

func (*Client) RegisterOnDialCallback 

func (c *Client) RegisterOnDialCallback(fn func())

func (*Client) Replace 

func (c *Client) Replace(item *Item) error

Replace writes the given item, but only if the server *does* already hold data for this key

func (*Client) Set 

func (c *Client) Set(item *Item) error

Set writes the given item, unconditionally.

func (*Client) SetCheckReconnectibleError 

func (c *Client) SetCheckReconnectibleError(f func(error) bool)

func (*Client) Touch 

func (c *Client) Touch(key string, seconds int32) (err error)

Touch updates the expiry for the given key. The seconds parameter is either a Unix timestamp or, if seconds is less than 1 month, the number of seconds into the future at which time the item will expire. Zero means the item has no expiration time. ErrCacheMiss is returned if the key is not in the cache. The key must be at most 250 bytes in length.

type CmdRunner 

type CmdRunner interface {
	ProtoType() string

	LegalKey(string) bool

	IsAuthSupported() bool
	Auth(rw *bufio.ReadWriter, username, password string) error
	Get(rw *bufio.ReadWriter, keys []string, cb func(*Item)) error
	GetMulti(rw *bufio.ReadWriter, keys []string, cb func(*Item)) error
	Populate(rw *bufio.ReadWriter, verb types.Verb, item *Item) error
	Delete(rw *bufio.ReadWriter, key string) error
	DeleteAll(rw *bufio.ReadWriter) error
	FlushAll(rw *bufio.ReadWriter) error
	Touch(rw *bufio.ReadWriter, keys []string, expiration int32) error
	IncrDecr(rw *bufio.ReadWriter, verb types.Verb, key string, delta uint64) (uint64, error)
	Ping(rw *bufio.ReadWriter) error
}

type ConnectTimeoutError 

type ConnectTimeoutError struct {
	Addr net.Addr
}

ConnectTimeoutError is the error type used when it takes too long to connect to the desired host. This level of detail can generally be ignored.

func (*ConnectTimeoutError) Error 

func (cte *ConnectTimeoutError) Error() string

type Item 

type Item = types.Item

type ServerList 

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

ServerList is a simple ServerSelector. Its zero value is usable.

func (*ServerList) Each 

func (ss *ServerList) Each(f func(net.Addr) error) error

Each iterates over each server calling the given function

func (*ServerList) PickServer 

func (ss *ServerList) PickServer(key string) (net.Addr, error)

func (*ServerList) SetServers 

func (ss *ServerList) SetServers(servers ...string) error

SetServers changes a ServerList's set of servers at runtime and is safe for concurrent use by multiple goroutines.

Each server is given equal weight. A server is given more weight if it's listed multiple times.

SetServers returns an error if any of the server names fail to resolve. No attempt is made to connect to the server. If any error is returned, no changes are made to the ServerList.

type ServerSelector 

type ServerSelector interface {
	// PickServer returns the server address that a given item
	// should be shared onto.
	PickServer(key string) (net.Addr, error)
	Each(func(net.Addr) error) error
}

ServerSelector is the interface that selects a memcache server as a function of the item's key.

All ServerSelector implementations must be safe for concurrent use by multiple goroutines.

Source Files

View all Source files

Directories

Path Synopsis
proto
bin
text

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