/
consume.go
188 lines (171 loc) · 4.07 KB
/
consume.go
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// Copyright (c) 2021 Terminus, Inc.
//
// Licensed 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 storekit
import (
"context"
"errors"
"time"
)
// BatchReader .
type BatchReader interface {
ReadN(buf []Data, timeout time.Duration) (int, error)
Confirm() error
Close() error
}
// BatchConsumeOptions .
type BatchConsumeOptions struct {
BufferSize int
ReadTimeout time.Duration
// ReadErrorHandler return err to exit, return nil to continue
ReadErrorHandler func(err error) error
// WriteErrorHandler return err to retry write, return nil to continue
WriteErrorHandler func(list []Data, err error) error
// ConfirmErrorHandler return err to exit, return nil to continue
ConfirmErrorHandler func(err error) error
Backoff TimerBackoff
Statistics ConsumeStatistics
}
// ErrExitConsume .
var ErrExitConsume = errors.New("exit consume")
// BatchConsume .
func BatchConsume(ctx context.Context, r BatchReader, w BatchWriter, opts *BatchConsumeOptions) error {
// timer backoff
backoff := opts.Backoff
if backoff == nil {
backoff = &MultiplierBackoff{
Base: opts.ReadTimeout,
Max: 16 * opts.ReadTimeout,
Factor: 2,
}
}
backoff.Reset()
// statistics
stats := opts.Statistics
if stats == nil {
stats = NopConsumeStatistics
}
// failed handlers
readErrorHandler := opts.ReadErrorHandler
writeErrorHandler := opts.WriteErrorHandler
confirmErrorHandler := opts.ConfirmErrorHandler
// check flusher
flusher, flush := w.(Flusher)
// init buffer
buf := make([]Data, opts.BufferSize, opts.BufferSize)
consumeLoop:
for {
// check exit
select {
case <-ctx.Done():
return nil
default:
}
// read with timeout
n, err := r.ReadN(buf, opts.ReadTimeout)
if err != nil {
if err == ErrExitConsume {
return nil
}
stats.ReadError(err)
if err := readErrorHandler(err); err != nil {
return err
}
select {
case <-ctx.Done():
return nil
case <-backoff.Wait():
}
continue
}
if n <= 0 {
continue
}
list := buf[0:n]
// write data
retryLoop:
for {
_, err := w.WriteN(list...)
if err == nil && flush {
err = flusher.Flush()
}
if err != nil {
if err == ErrExitConsume {
return nil
}
stats.WriteError(list, err)
if err := writeErrorHandler(list, err); err == nil {
// skip data
continue consumeLoop
}
select {
case <-ctx.Done():
return nil
case <-backoff.Wait():
}
continue retryLoop
}
err = r.Confirm()
if err != nil {
stats.ConfirmError(list, err)
if err = confirmErrorHandler(err); err != nil {
return err
}
}
stats.Success(list)
backoff.Reset()
break
}
}
}
// NewMockBatchReader .
func NewMockBatchReader(ctx context.Context, interval time.Duration, batchSize int, creator func() interface{}) BatchReader {
ctx, cancel := context.WithCancel(ctx)
return &mockBatchReader{
ctx: ctx,
cancel: cancel,
timer: time.NewTimer(0),
size: batchSize,
creator: creator,
}
}
// mockBatchReader .
type mockBatchReader struct {
ctx context.Context
cancel func()
interval time.Duration
timer *time.Timer
size int
creator func() interface{}
}
func (r *mockBatchReader) ReadN(buf []Data, timeout time.Duration) (int, error) {
size := r.size
if len(buf) < size {
size = len(buf)
}
select {
case <-r.ctx.Done():
return 0, nil
case <-r.timer.C:
for i := 0; i < size; i++ {
buf[i] = r.creator()
}
}
r.timer.Reset(r.interval)
return size, nil
}
func (r *mockBatchReader) Confirm() error { return nil }
func (r *mockBatchReader) Close() error {
r.cancel()
return nil
}