forked from apache/beam
/
datasink.go
94 lines (81 loc) · 2.57 KB
/
datasink.go
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// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package exec
import (
"bytes"
"context"
"fmt"
"io"
"sync/atomic"
"time"
"github.com/apache/beam/sdks/go/pkg/beam/core/graph/coder"
"github.com/apache/beam/sdks/go/pkg/beam/internal/errors"
"github.com/apache/beam/sdks/go/pkg/beam/log"
)
// DataSink is a Node.
type DataSink struct {
UID UnitID
SID StreamID
Coder *coder.Coder
enc ElementEncoder
wEnc WindowEncoder
w io.WriteCloser
count int64
start time.Time
}
func (n *DataSink) ID() UnitID {
return n.UID
}
func (n *DataSink) Up(ctx context.Context) error {
n.enc = MakeElementEncoder(coder.SkipW(n.Coder))
n.wEnc = MakeWindowEncoder(n.Coder.Window)
return nil
}
func (n *DataSink) StartBundle(ctx context.Context, id string, data DataContext) error {
w, err := data.Data.OpenWrite(ctx, n.SID)
if err != nil {
return err
}
n.w = w
atomic.StoreInt64(&n.count, 0)
n.start = time.Now()
return nil
}
func (n *DataSink) ProcessElement(ctx context.Context, value *FullValue, values ...ReStream) error {
// Marshal the pieces into a temporary buffer since they must be transmitted on FnAPI as a single
// unit.
var b bytes.Buffer
atomic.AddInt64(&n.count, 1)
if err := EncodeWindowedValueHeader(n.wEnc, value.Windows, value.Timestamp, &b); err != nil {
return err
}
if err := n.enc.Encode(value, &b); err != nil {
return errors.WithContextf(err, "encoding element %v with coder %v", value, n.enc)
}
if _, err := n.w.Write(b.Bytes()); err != nil {
return err
}
return nil
}
func (n *DataSink) FinishBundle(ctx context.Context) error {
log.Infof(ctx, "DataSink: %d elements in %d ns", atomic.LoadInt64(&n.count), time.Now().Sub(n.start))
return n.w.Close()
}
func (n *DataSink) Down(ctx context.Context) error {
return nil
}
func (n *DataSink) String() string {
return fmt.Sprintf("DataSink[%v] Coder:%v", n.SID, n.Coder)
}