mirror of
https://github.com/prometheus-community/windows_exporter.git
synced 2026-10-17 18:19:04 +02:00
90 lines
2.2 KiB
Go
90 lines
2.2 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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//go:build windows
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package pdh
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import (
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"fmt"
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"sync"
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)
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// Query is a PDH query that several collectors share, so one
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// PdhCollectQueryData samples all of them. Windows serves counter samples of
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// a process one at a time, so every query waits for the others during a
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// scrape; collectors that are always read together, such as the IPv4 and IPv6
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// objects of a protocol, wait only once in one query.
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//
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// Create the collectors with [NewQueryCollector]. [Query.Collect] takes the
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// sample; [Collector.Collect] of a collector in the query reads the latest
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// sample without taking a new one.
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type Query struct {
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mu sync.Mutex
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handle pdhQueryHandle
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}
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// NewQuery opens a query for [NewQueryCollector]. The caller must Close it
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// after the collectors in it.
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func NewQuery() (*Query, error) {
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if err := Load(); err != nil {
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return nil, err
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}
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var handle pdhQueryHandle
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if ret := OpenQuery(0, 0, &handle); ret != ErrorSuccess {
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return nil, NewPdhError(ret)
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}
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return &Query{handle: handle}, nil
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}
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// Collect takes one sample of all counters in the query.
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func (q *Query) Collect() error {
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if q == nil {
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return ErrPerformanceCounterNotInitialized
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}
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q.mu.Lock()
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defer q.mu.Unlock()
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if q.handle == 0 {
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return ErrPerformanceCounterNotInitialized
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}
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if ret := CollectQueryData(q.handle); ret != ErrorSuccess {
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return fmt.Errorf("failed to collect query data: %w", NewPdhError(ret))
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}
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return nil
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}
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// Close closes the query and all counters in it.
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func (q *Query) Close() {
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if q == nil {
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return
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}
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q.mu.Lock()
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defer q.mu.Unlock()
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if q.handle != 0 {
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CloseQuery(q.handle)
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}
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q.handle = 0
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}
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