首先查阅了官方文档prometheus go application，发现极其简单，
使用的是go func()方式去
后来看了下gauge的方式，到了go版本的文档，
发现一个问题，就是示例中的Inc无法自增
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package main
import (
"log"
"net/http"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
type metrics struct {
cpuTemp prometheus.Gauge
hdFailures *prometheus.CounterVec
}
func NewMetrics(reg prometheus.Registerer) *metrics {
m := &metrics{
cpuTemp: prometheus.NewGauge(prometheus.GaugeOpts{
Name: "cpu_temperature_celsius",
Help: "Current temperature of the CPU.",
}),
hdFailures: prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "hd_errors_total",
Help: "Number of hard-disk errors.",
},
[]string{"device"},
),
}
reg.MustRegister(m.cpuTemp)
reg.MustRegister(m.hdFailures)
return m
}
func main() {
// Create a non-global registry.
reg := prometheus.NewRegistry()
// Create new metrics and register them using the custom registry.
m := NewMetrics(reg)
// Set values for the new created metrics.
m.cpuTemp.Set(65.3)
m.hdFailures.With(prometheus.Labels{"device":"/dev/sda"}).Inc()
// Expose metrics and custom registry via an HTTP server
// using the HandleFor function. "/metrics" is the usual endpoint for that.
http.Handle("/metrics", promhttp.HandlerFor(reg, promhttp.HandlerOpts{Registry: reg}))
log.Fatal(http.ListenAndServe(":8080", nil))
}
|
研究了挺多办法，最后我还是放弃了，准备用exporter的正规方式collect方式
去编写。
建议阅读官方文档和github的源码
https://pkg.go.dev/github.com/prometheus/client_golang/prometheus#Collector
几个exporter的代码都可以借鉴一下
https://github.com/treydock/ssh_exporter/blob/master/collector/collector.go
https://github.com/Lusitaniae/apache_exporter/blob/master/collector/collector.go
这些exporter的入口都差不多，所以仿照写了一下，
https://github.com/liuliancao/demo-prometheus-exporter
简单说下，几个重要的点
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type Exporter struct {
host string
version *prometheus.Desc
total *prometheus.GaugeVec
available *prometheus.GaugeVec
logger log.Logger
}
func NewExporter(logger log.Logger, config *Config) *Exporter {
return &Exporter{
host: config.host,
logger: logger,
version: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "version"),
"demo exporter version",
nil,
nil),
total: prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Namespace: namespace,
Name: "total",
Help: "demo total",
},
[]string{"region_id", "instance_id"},
), // 定义gauge类型带标签region_id, instance_id的数据结构
}
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collector的describe和collect方法编写，一个collector都需要这两种方法，
否则会报错。
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func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
ch <- e.version
e.total.Describe(ch)
}
func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
ch <- prometheus.MustNewConstMetric(e.version, prometheus.GaugeValue, 0.8)
e.total.Reset()
start++
e.total.With(prometheus.Labels{"region_id": "region1", "instance_id": "instance1"}).Set(float64(start))
e.total.Collect(ch)
}
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我这边理解是每个采集值都要在describe和collect体现。
对于有标签，动态的gauge的，需要通过With().Set()方法更改
并且需要增加 e.total.Collect(ch) 这样的方法去更新。
这样执行的结果就是demo_total这个值每次都会+1，从2开始。