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https://github.com/VictoriaMetrics/VictoriaMetrics.git
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7f4fb34182
It is better developing vmctl tool in VictoriaMetrics repository, so it could be released together with the rest of vmutils tools such as vmalert, vmagent, vmbackup, vmrestore and vmauth.
49 lines
1.4 KiB
Go
49 lines
1.4 KiB
Go
// Copyright 2018 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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// +build linux,!appengine
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package util
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import (
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"bytes"
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"os"
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"syscall"
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)
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// SysReadFile is a simplified ioutil.ReadFile that invokes syscall.Read directly.
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// https://github.com/prometheus/node_exporter/pull/728/files
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//
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// Note that this function will not read files larger than 128 bytes.
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func SysReadFile(file string) (string, error) {
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f, err := os.Open(file)
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if err != nil {
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return "", err
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}
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defer f.Close()
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// On some machines, hwmon drivers are broken and return EAGAIN. This causes
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// Go's ioutil.ReadFile implementation to poll forever.
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//
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// Since we either want to read data or bail immediately, do the simplest
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// possible read using syscall directly.
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const sysFileBufferSize = 128
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b := make([]byte, sysFileBufferSize)
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n, err := syscall.Read(int(f.Fd()), b)
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if err != nil {
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return "", err
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}
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return string(bytes.TrimSpace(b[:n])), nil
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}
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