cache

package
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Published: Aug 17, 2022 License: AGPL-3.0 Imports: 28 Imported by: 0

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Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func StringToBytes

func StringToBytes(s string) []byte

StringToBytes converts string to byte slice. (copied from vendor/github.com/go-redis/redis/v8/internal/util/unsafe.go)

Types

type BackgroundConfig

type BackgroundConfig struct {
	WriteBackGoroutines int `yaml:"writeback_goroutines"`
	WriteBackBuffer     int `yaml:"writeback_buffer"`
}

BackgroundConfig is config for a Background Cache.

func (*BackgroundConfig) RegisterFlagsWithPrefix

func (cfg *BackgroundConfig) RegisterFlagsWithPrefix(prefix string, description string, f *flag.FlagSet)

RegisterFlagsWithPrefix adds the flags required to config this to the given FlagSet

type Cache

type Cache interface {
	Store(ctx context.Context, key []string, buf [][]byte)
	Fetch(ctx context.Context, keys []string) (found []string, bufs [][]byte, missing []string)
	Stop()
}

Cache byte arrays by key.

NB we intentionally do not return errors in this interface - caching is best effort by definition. We found that when these methods did return errors, the caller would just log them - so its easier for implementation to do that. Whatsmore, we found partially successful Fetchs were often treated as failed when they returned an error.

func NewBackground

func NewBackground(name string, cfg BackgroundConfig, cache Cache, reg prometheus.Registerer) Cache

NewBackground returns a new Cache that does stores on background goroutines.

func NewMockCache

func NewMockCache() Cache

NewMockCache makes a new MockCache.

type Memcached

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

Memcached type caches chunks in memcached

func NewMemcached

func NewMemcached(cfg MemcachedConfig, client MemcachedClient, name string, reg prometheus.Registerer, logger log.Logger) *Memcached

NewMemcached makes a new Memcached.

func (*Memcached) Fetch

func (c *Memcached) Fetch(ctx context.Context, keys []string) (found []string, bufs [][]byte, missed []string)

Fetch gets keys from the cache. The keys that are found must be in the order of the keys requested.

func (*Memcached) Stop

func (c *Memcached) Stop()

Stop does nothing.

func (*Memcached) Store

func (c *Memcached) Store(ctx context.Context, keys []string, bufs [][]byte)

Store stores the key in the cache.

type MemcachedClient

type MemcachedClient interface {
	GetMulti(keys []string) (map[string]*memcache.Item, error)
	Set(item *memcache.Item) error
}

MemcachedClient interface exists for mocking memcacheClient.

func NewMemcachedClient

func NewMemcachedClient(cfg MemcachedClientConfig, name string, r prometheus.Registerer, logger log.Logger) MemcachedClient

NewMemcachedClient creates a new MemcacheClient that gets its server list from SRV and updates the server list on a regular basis.

type MemcachedClientConfig

type MemcachedClientConfig struct {
	Host           string        `yaml:"host"`
	Service        string        `yaml:"service"`
	Addresses      string        `yaml:"addresses"` // EXPERIMENTAL.
	Timeout        time.Duration `yaml:"timeout"`
	MaxIdleConns   int           `yaml:"max_idle_conns"`
	MaxItemSize    int           `yaml:"max_item_size"`
	UpdateInterval time.Duration `yaml:"update_interval"`
	ConsistentHash bool          `yaml:"consistent_hash"`
	CBFailures     uint          `yaml:"circuit_breaker_consecutive_failures"`
	CBTimeout      time.Duration `yaml:"circuit_breaker_timeout"`  // reset error count after this long
	CBInterval     time.Duration `yaml:"circuit_breaker_interval"` // remain closed for this long after CBFailures errors
}

MemcachedClientConfig defines how a MemcachedClient should be constructed.

func (*MemcachedClientConfig) RegisterFlagsWithPrefix

func (cfg *MemcachedClientConfig) RegisterFlagsWithPrefix(prefix, description string, f *flag.FlagSet)

RegisterFlagsWithPrefix adds the flags required to config this to the given FlagSet

type MemcachedConfig

type MemcachedConfig struct {
	Expiration time.Duration `yaml:"expiration"`

	BatchSize   int `yaml:"batch_size"`
	Parallelism int `yaml:"parallelism"`
}

MemcachedConfig is config to make a Memcached

func (*MemcachedConfig) RegisterFlagsWithPrefix

func (cfg *MemcachedConfig) RegisterFlagsWithPrefix(prefix, description string, f *flag.FlagSet)

RegisterFlagsWithPrefix adds the flags required to config this to the given FlagSet

type MemcachedJumpHashSelector

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

MemcachedJumpHashSelector implements the memcache.ServerSelector interface. MemcachedJumpHashSelector utilizes a jump hash to distribute keys to servers.

While adding or removing servers only requires 1/N keys to move, servers are treated as a stack and can only be pushed/popped. Therefore, MemcachedJumpHashSelector works best for servers with consistent DNS names where the naturally sorted order is predictable.

func (*MemcachedJumpHashSelector) Each

func (s *MemcachedJumpHashSelector) Each(f func(net.Addr) error) error

Each iterates over each server and calls the given function. If f returns a non-nil error, iteration will stop and that error will be returned.

func (*MemcachedJumpHashSelector) PickServer

func (s *MemcachedJumpHashSelector) PickServer(key string) (net.Addr, error)

PickServer returns the server address that a given item should be shared onto.

func (*MemcachedJumpHashSelector) SetServers

func (s *MemcachedJumpHashSelector) SetServers(servers ...string) error

SetServers changes a MemcachedJumpHashSelector'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 occurs, no changes are made to the internal server list.

To minimize the number of rehashes for keys when scaling the number of servers in subsequent calls to SetServers, servers are stored in natural sort order.

type RedisCache

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

RedisCache type caches chunks in redis

func NewRedisCache

func NewRedisCache(name string, redisClient *RedisClient, reg prometheus.Registerer, logger log.Logger) *RedisCache

NewRedisCache creates a new RedisCache

func (*RedisCache) Fetch

func (c *RedisCache) Fetch(ctx context.Context, keys []string) (found []string, bufs [][]byte, missed []string)

Fetch gets keys from the cache. The keys that are found must be in the order of the keys requested.

func (*RedisCache) Stop

func (c *RedisCache) Stop()

Stop stops the redis client.

func (*RedisCache) Store

func (c *RedisCache) Store(ctx context.Context, keys []string, bufs [][]byte)

Store stores the key in the cache.

type RedisClient

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

func NewRedisClient

func NewRedisClient(cfg *RedisConfig) *RedisClient

NewRedisClient creates Redis client

func (*RedisClient) Close

func (c *RedisClient) Close() error

func (*RedisClient) MGet

func (c *RedisClient) MGet(ctx context.Context, keys []string) ([][]byte, error)

func (*RedisClient) MSet

func (c *RedisClient) MSet(ctx context.Context, keys []string, values [][]byte) error

func (*RedisClient) Ping

func (c *RedisClient) Ping(ctx context.Context) error

type RedisConfig

type RedisConfig struct {
	Endpoint           string         `yaml:"endpoint"`
	MasterName         string         `yaml:"master_name"`
	Timeout            time.Duration  `yaml:"timeout"`
	Expiration         time.Duration  `yaml:"expiration"`
	DB                 int            `yaml:"db"`
	PoolSize           int            `yaml:"pool_size"`
	Password           flagext.Secret `yaml:"password"`
	SentinelPassword   flagext.Secret `yaml:"sentinel_password"`
	EnableTLS          bool           `yaml:"tls_enabled"`
	InsecureSkipVerify bool           `yaml:"tls_insecure_skip_verify"`
	IdleTimeout        time.Duration  `yaml:"idle_timeout"`
	MaxConnAge         time.Duration  `yaml:"max_connection_age"`
}

RedisConfig defines how a RedisCache should be constructed.

func (*RedisConfig) RegisterFlagsWithPrefix

func (cfg *RedisConfig) RegisterFlagsWithPrefix(prefix, description string, f *flag.FlagSet)

RegisterFlagsWithPrefix adds the flags required to config this to the given FlagSet

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