Move sync

util/sync/sync.go

@@ -0,0 +1,115 @@
+// Package syncs will sync multiple stores
+package sync
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/ef-ds/deque"
+	"github.com/micro/go-micro/v2/store"
+	"github.com/pkg/errors"
+)
+
+// Sync implements a sync in for stores
+type Sync interface {
+	// Implements the store interface
+	store.Store
+	// Force a full sync
+	Sync() error
+}
+
+type syncStore struct {
+	storeOpts           store.Options
+	syncOpts            Options
+	pendingWrites       []*deque.Deque
+	pendingWriteTickers []*time.Ticker
+	sync.RWMutex
+}
+
+// NewSync returns a new Sync
+func NewSync(opts ...Option) Sync {
+	c := &syncStore{}
+	for _, o := range opts {
+		o(&c.syncOpts)
+	}
+	if c.syncOpts.SyncInterval == 0 {
+		c.syncOpts.SyncInterval = 1 * time.Minute
+	}
+	if c.syncOpts.SyncMultiplier == 0 {
+		c.syncOpts.SyncMultiplier = 5
+	}
+	return c
+}
+
+func (c *syncStore) Close() error {
+	return nil
+}
+
+// Init initialises the storeOptions
+func (c *syncStore) Init(opts ...store.Option) error {
+	for _, o := range opts {
+		o(&c.storeOpts)
+	}
+	if len(c.syncOpts.Stores) == 0 {
+		return errors.New("the sync has no stores")
+	}
+	if c.storeOpts.Context == nil {
+		return errors.New("please provide a context to the sync. Cancelling the context signals that the sync is being disposed and syncs the sync")
+	}
+	for _, s := range c.syncOpts.Stores {
+		if err := s.Init(); err != nil {
+			return errors.Wrapf(err, "Store %s failed to Init()", s.String())
+		}
+	}
+	c.pendingWrites = make([]*deque.Deque, len(c.syncOpts.Stores)-1)
+	c.pendingWriteTickers = make([]*time.Ticker, len(c.syncOpts.Stores)-1)
+	for i := 0; i < len(c.pendingWrites); i++ {
+		c.pendingWrites[i] = deque.New()
+		c.pendingWrites[i].Init()
+		c.pendingWriteTickers[i] = time.NewTicker(c.syncOpts.SyncInterval * time.Duration(intpow(c.syncOpts.SyncMultiplier, int64(i))))
+	}
+	go c.syncManager()
+	return nil
+}
+
+// Options returns the sync's store options
+func (c *syncStore) Options() store.Options {
+	return c.storeOpts
+}
+
+// String returns a printable string describing the sync
+func (c *syncStore) String() string {
+	backends := make([]string, len(c.syncOpts.Stores))
+	for i, s := range c.syncOpts.Stores {
+		backends[i] = s.String()
+	}
+	return fmt.Sprintf("sync %v", backends)
+}
+
+func (c *syncStore) List(opts ...store.ListOption) ([]string, error) {
+	return c.syncOpts.Stores[0].List(opts...)
+}
+
+func (c *syncStore) Read(key string, opts ...store.ReadOption) ([]*store.Record, error) {
+	return c.syncOpts.Stores[0].Read(key, opts...)
+}
+
+func (c *syncStore) Write(r *store.Record, opts ...store.WriteOption) error {
+	return c.syncOpts.Stores[0].Write(r, opts...)
+}
+
+// Delete removes a key from the sync
+func (c *syncStore) Delete(key string, opts ...store.DeleteOption) error {
+	return c.syncOpts.Stores[0].Delete(key, opts...)
+}
+
+func (c *syncStore) Sync() error {
+	return nil
+}
+
+type internalRecord struct {
+	key       string
+	value     []byte
+	expiresAt time.Time
+}