88 lines
2.2 KiB
Go
88 lines
2.2 KiB
Go
// Licensed to Elasticsearch B.V. under one or more contributor
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// license agreements. See the NOTICE file distributed with
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// this work for additional information regarding copyright
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// ownership. Elasticsearch B.V. licenses this file to you under
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// the Apache License, Version 2.0 (the "License"); you may
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// not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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package readfile
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import (
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"errors"
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"time"
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"github.com/elastic/beats/filebeat/reader"
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)
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var (
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errTimeout = errors.New("timeout")
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)
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// timeoutProcessor will signal some configurable timeout error if no
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// new line can be returned in time.
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type TimeoutReader struct {
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reader reader.Reader
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timeout time.Duration
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signal error
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running bool
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ch chan lineMessage
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}
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type lineMessage struct {
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line reader.Message
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err error
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}
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// New returns a new timeout reader from an input line reader.
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func NewTimeoutReader(reader reader.Reader, signal error, t time.Duration) *TimeoutReader {
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if signal == nil {
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signal = errTimeout
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}
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return &TimeoutReader{
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reader: reader,
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signal: signal,
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timeout: t,
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ch: make(chan lineMessage, 1),
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}
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}
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// Next returns the next line. If no line was returned before timeout, the
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// configured timeout error is returned.
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// For handline timeouts a goroutine is started for reading lines from
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// configured line reader. Only when underlying reader returns an error, the
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// goroutine will be finished.
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func (r *TimeoutReader) Next() (reader.Message, error) {
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if !r.running {
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r.running = true
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go func() {
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for {
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message, err := r.reader.Next()
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r.ch <- lineMessage{message, err}
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if err != nil {
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break
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}
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}
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}()
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}
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select {
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case msg := <-r.ch:
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if msg.err != nil {
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r.running = false
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}
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return msg.line, msg.err
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case <-time.After(r.timeout):
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return reader.Message{}, r.signal
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}
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}
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