Golang CounterOpts.ConstLabels方法代码示例

func NewCounterVec1(opts prometheus.CounterOpts, labelName string, labelValues []string) *CounterVec1 {
	v := CounterVec1{
		desc: prometheus.NewDesc(
			prometheus.BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
			opts.Help,
			[]string{labelName},
			opts.ConstLabels,
		),
		counters: map[string]prometheus.Counter{},
	}
	for _, lvs := range labelValues {
		labels := prometheus.Labels{}
		for cl, cv := range opts.ConstLabels {
			labels[cl] = cv
		}
		labels[labelName] = lvs
		opts.ConstLabels = labels
		v.counters[lvs] = prometheus.NewCounter(opts)
	}
	return &v
}

// NewCounterVec2 creates a CounterVec2, given counter options and definitions
// of label names and label values.
func NewCounterVec2(opts prometheus.CounterOpts, labelNames [2]string, labelValues [][2]string) *CounterVec2 {
	v := CounterVec2{
		desc: prometheus.NewDesc(
			prometheus.BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
			opts.Help,
			labelNames[:],
			opts.ConstLabels,
		),
		counters: map[[2]string]prometheus.Counter{},
	}
	for _, lvs := range labelValues {
		labels := prometheus.Labels{}
		for cl, cv := range opts.ConstLabels {
			labels[cl] = cv
		}
		for i, l := range labelNames {
			labels[l] = lvs[i]
		}
		opts.ConstLabels = labels
		v.counters[lvs] = prometheus.NewCounter(opts)
	}
	return &v
}

//.........这里部分代码省略.........

	// Prometheus will not allow you to ever export metrics with
	// inconsistent help strings or label names. After unregistering, the
	// unregistered metrics will cease to show up in the /metrics HTTP
	// response, but the registry still remembers that those metrics had
	// been exported before. For this example, we will now choose a
	// different name. (In a real program, you would obviously not export
	// the obsolete metric in the first place.)
	taskCounterVec = prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Subsystem: "worker_pool",
			Name:      "completed_tasks_by_id",
			Help:      "Total number of tasks completed.",
		},
		[]string{"worker_id"},
	)
	if err := prometheus.Register(taskCounterVec); err != nil {
		fmt.Println("taskCounterVec not registered:", err)
	} else {
		fmt.Println("taskCounterVec registered.")
	}
	// Finally it worked!

	// The workers have to tell taskCounterVec their id to increment the
	// right element in the metric vector.
	taskCounterVec.WithLabelValues("42").Inc() // Code from worker 42.

	// Each worker could also keep a reference to their own counter element
	// around. Pick the counter at initialization time of the worker.
	myCounter := taskCounterVec.WithLabelValues("42") // From worker 42 initialization code.
	myCounter.Inc()                                   // Somewhere in the code of that worker.

	// Note that something like WithLabelValues("42", "spurious arg") would
	// panic (because you have provided too many label values). If you want
	// to get an error instead, use GetMetricWithLabelValues(...) instead.
	notMyCounter, err := taskCounterVec.GetMetricWithLabelValues("42", "spurious arg")
	if err != nil {
		fmt.Println("Worker initialization failed:", err)
	}
	if notMyCounter == nil {
		fmt.Println("notMyCounter is nil.")
	}

	// A different (and somewhat tricky) approach is to use
	// ConstLabels. ConstLabels are pairs of label names and label values
	// that never change. You might ask what those labels are good for (and
	// rightfully so - if they never change, they could as well be part of
	// the metric name). There are essentially two use-cases: The first is
	// if labels are constant throughout the lifetime of a binary execution,
	// but they vary over time or between different instances of a running
	// binary. The second is what we have here: Each worker creates and
	// registers an own Counter instance where the only difference is in the
	// value of the ConstLabels. Those Counters can all be registered
	// because the different ConstLabel values guarantee that each worker
	// will increment a different Counter metric.
	counterOpts := prometheus.CounterOpts{
		Subsystem:   "worker_pool",
		Name:        "completed_tasks",
		Help:        "Total number of tasks completed.",
		ConstLabels: prometheus.Labels{"worker_id": "42"},
	}
	taskCounterForWorker42 := prometheus.NewCounter(counterOpts)
	if err := prometheus.Register(taskCounterForWorker42); err != nil {
		fmt.Println("taskCounterVForWorker42 not registered:", err)
	} else {
		fmt.Println("taskCounterForWorker42 registered.")
	}
	// Obviously, in real code, taskCounterForWorker42 would be a member
	// variable of a worker struct, and the "42" would be retrieved with a
	// GetId() method or something. The Counter would be created and
	// registered in the initialization code of the worker.

	// For the creation of the next Counter, we can recycle
	// counterOpts. Just change the ConstLabels.
	counterOpts.ConstLabels = prometheus.Labels{"worker_id": "2001"}
	taskCounterForWorker2001 := prometheus.NewCounter(counterOpts)
	if err := prometheus.Register(taskCounterForWorker2001); err != nil {
		fmt.Println("taskCounterVForWorker2001 not registered:", err)
	} else {
		fmt.Println("taskCounterForWorker2001 registered.")
	}

	taskCounterForWorker2001.Inc()
	taskCounterForWorker42.Inc()
	taskCounterForWorker2001.Inc()

	// Yet another approach would be to turn the workers themselves into
	// Collectors and register them. See the Collector example for details.

	// Output:
	// taskCounter registered.
	// taskCounterVec not registered: a previously registered descriptor with the same fully-qualified name as Desc{fqName: "worker_pool_completed_tasks_total", help: "Total number of tasks completed.", constLabels: {}, variableLabels: [worker_id]} has different label names or a different help string
	// taskCounter unregistered.
	// taskCounterVec not registered: a previously registered descriptor with the same fully-qualified name as Desc{fqName: "worker_pool_completed_tasks_total", help: "Total number of tasks completed.", constLabels: {}, variableLabels: [worker_id]} has different label names or a different help string
	// taskCounterVec registered.
	// Worker initialization failed: inconsistent label cardinality
	// notMyCounter is nil.
	// taskCounterForWorker42 registered.
	// taskCounterForWorker2001 registered.
}