mirror of
https://github.com/prometheus-community/windows_exporter.git
synced 2026-09-01 03:31:25 +02:00
100 lines
1.9 KiB
Go
100 lines
1.9 KiB
Go
// SPDX-License-Identifier: Apache-2.0
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//
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// Copyright The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may 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, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package log
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import (
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"bytes"
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"io"
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"sync"
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)
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const defaultNonBlockingWriterBufferSize = 1024
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type nonBlockingWriter struct {
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writer io.Writer
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queue chan []byte
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stop chan struct{}
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workerDone chan struct{}
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mu sync.RWMutex
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closed bool
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}
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func newNonBlockingWriter(writer io.Writer, queueSize int) *nonBlockingWriter {
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if queueSize <= 0 {
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queueSize = defaultNonBlockingWriterBufferSize
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}
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w := &nonBlockingWriter{
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writer: writer,
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queue: make(chan []byte, queueSize),
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stop: make(chan struct{}),
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workerDone: make(chan struct{}),
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}
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go func() {
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defer close(w.workerDone)
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for {
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select {
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case p := <-w.queue:
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_, _ = w.writer.Write(p)
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case <-w.stop:
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for {
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select {
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case p := <-w.queue:
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_, _ = w.writer.Write(p)
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default:
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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 w
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}
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func (w *nonBlockingWriter) Write(p []byte) (int, error) {
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msg := bytes.Clone(p)
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w.mu.RLock()
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defer w.mu.RUnlock()
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if w.closed {
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return 0, io.ErrClosedPipe
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}
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select {
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case w.queue <- msg:
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default:
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}
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return len(p), nil
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}
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func (w *nonBlockingWriter) Close() error {
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w.mu.Lock()
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if !w.closed {
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w.closed = true
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close(w.stop)
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}
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w.mu.Unlock()
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<-w.workerDone
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return nil
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}
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