155 lines
3.7 KiB
Go
155 lines
3.7 KiB
Go
package mongo
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import (
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"context"
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"fmt"
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"sync"
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"time"
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"github.com/globalsign/mgo"
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log "github.com/go-pkgz/lgr"
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)
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// BufferedWriter defines interface for writes and flush
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type BufferedWriter interface {
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Write(rec interface{}) error
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Flush() error
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Close() error
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}
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// BufferedWriterMgo collects records in local buffer and flushes them as filled. Thread safe
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// by default using both DB and collection from provided connection.
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// Collection can be customized by WithCollection method. Optional flush duration to save on interval
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type BufferedWriterMgo struct {
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connection *Connection
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bufferSize int
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collection string
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flushDuration time.Duration
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ctx context.Context
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cancel context.CancelFunc
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buffer []interface{}
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lock sync.Mutex
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lastWriteTime time.Time
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once sync.Once
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}
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// NewBufferedWriter makes batch writer for given size and connection
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func NewBufferedWriter(size int, connection *Connection) *BufferedWriterMgo {
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if size == 0 {
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size = 1
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}
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return &BufferedWriterMgo{
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bufferSize: size,
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buffer: make([]interface{}, 0, size+1),
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connection: connection,
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}
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}
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// WithCollection sets custom collection to use with writer
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func (bw *BufferedWriterMgo) WithCollection(collection string) *BufferedWriterMgo {
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bw.collection = collection
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return bw
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}
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// WithAutoFlush sets auto flush duration
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func (bw *BufferedWriterMgo) WithAutoFlush(duration time.Duration) *BufferedWriterMgo {
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bw.flushDuration = duration
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if duration > 0 { // activate background auto-flush
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bw.once.Do(func() {
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bw.ctx, bw.cancel = context.WithCancel(context.Background())
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ticker := time.NewTicker(duration)
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go func() {
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defer bw.cancel()
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for {
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select {
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case <-ticker.C:
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var shouldFlush bool
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_ = bw.synced(func() error {
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shouldFlush = time.Now().After(bw.lastWriteTime.Add(bw.flushDuration)) && len(bw.buffer) > 0
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return nil
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})
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if shouldFlush {
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if err := bw.Flush(); err != nil {
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log.Printf("[WARN] flush failed, %s", err)
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}
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}
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case <-bw.ctx.Done():
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return
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}
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}
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}()
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})
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}
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return bw
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}
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// Write to buffer and, as filled, to mongo. If flushDuration defined check for automatic flush
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func (bw *BufferedWriterMgo) Write(rec interface{}) error {
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return bw.synced(func() error {
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bw.lastWriteTime = time.Now()
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bw.buffer = append(bw.buffer, rec)
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if len(bw.buffer) >= bw.bufferSize {
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if err := bw.writeBuffer(); err != nil {
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return fmt.Errorf("failed to write to %s, %s", bw.connection, err)
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}
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bw.buffer = bw.buffer[0:0]
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}
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return nil
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})
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}
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// Flush writes everything left in buffer to mongo
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func (bw *BufferedWriterMgo) Flush() error {
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err := bw.synced(func() error {
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err := bw.writeBuffer()
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bw.buffer = bw.buffer[0:0]
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return err
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})
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if err != nil {
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return fmt.Errorf("failed to flush to %s, %s", bw.connection, err)
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}
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return nil
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}
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// Close flushes all in-fly records and terminates background auto-flusher
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func (bw *BufferedWriterMgo) Close() (err error) {
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return bw.synced(func() error {
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err = bw.writeBuffer()
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if bw.flushDuration > 0 {
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bw.cancel()
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<-bw.ctx.Done()
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}
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return err
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})
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}
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// writeBuffer sends all collected records to mongo
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func (bw *BufferedWriterMgo) writeBuffer() (err error) {
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if len(bw.buffer) == 0 {
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return nil
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}
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if bw.collection == "" { // no custom collection
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err = bw.connection.WithCollection(func(coll *mgo.Collection) error {
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return coll.Insert(bw.buffer...)
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})
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}
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if bw.collection != "" { // with custom collection
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err = bw.connection.WithCustomCollection(bw.collection, func(coll *mgo.Collection) error {
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return coll.Insert(bw.buffer...)
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})
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}
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return err
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}
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func (bw *BufferedWriterMgo) synced(fn func() error) error {
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bw.lock.Lock()
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defer bw.lock.Unlock()
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return fn()
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}
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