github.com/juju/juju@v0.0.0-20240430160146-1752b71fcf00/apiserver/apiservermetrics.go

// Copyright 2017 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.

package apiserver

import (
	"fmt"
	"runtime"

	"github.com/prometheus/client_golang/prometheus"

	"github.com/juju/juju/apiserver/observer/metricobserver"
	"github.com/juju/juju/version"
)

const (
	apiserverMetricsNamespace   = "juju"
	apiserverSubsystemNamespace = "apiserver"
)

const (
	// MetricLabelEndpoint defines a constant for the APIConnections and
	// PingFailureCount Labels
	MetricLabelEndpoint = "endpoint"

	// MetricLabelModelUUID defines a constant for the PingFailureCount and
	// LogWriteCount Labels
	// Note: prometheus doesn't allow hyphens only underscores
	MetricLabelModelUUID = "model_uuid"

	// MetricLabelState defines a constant for the state Label
	MetricLabelState = "state"

	// MetricLabelHost defines a host constant for the Requests Label
	MetricLabelHost = "host"

	// MetricLabelStatus defines a status constant for the Requests Label
	MetricLabelStatus = "status"

	// MetricLabelVersion is the metric for the Juju Version of the controller
	MetricLabelVersion = "version"
)

// MetricAPIConnectionsLabelNames defines a series of labels for the
// APIConnections metric.
var MetricAPIConnectionsLabelNames = []string{
	MetricLabelEndpoint,
}

// MetricPingFailureLabelNames defines a series of labels for the PingFailure
// metric.
var MetricPingFailureLabelNames = []string{
	MetricLabelModelUUID,
	MetricLabelEndpoint,
}

// MetricLogLabelNames defines a series of labels for the LogWrite and LogRead
// metric
var MetricLogLabelNames = []string{
	MetricLabelModelUUID,
	MetricLabelState,
}

// MetricTotalRequestsWithStatusLabelNames defines a series of labels for the
// TotalRequests metric.
var MetricTotalRequestsWithStatusLabelNames = []string{
	MetricLabelModelUUID,
	MetricLabelHost,
	MetricLabelStatus,
}

// MetricTotalRequestsLabelNames defines a series of labels for the
// TotalRequests metric.
var MetricTotalRequestsLabelNames = []string{
	MetricLabelModelUUID,
	MetricLabelHost,
}

// Collector is a prometheus.Collector that collects metrics based
// on apiserver status.
type Collector struct {
	BuildInfo        prometheus.Gauge
	TotalConnections prometheus.Counter

	LoginAttempts      prometheus.Gauge
	APIConnections     *prometheus.GaugeVec
	APIRequestDuration *prometheus.SummaryVec

	PingFailureCount *prometheus.CounterVec

	LogWriteCount *prometheus.CounterVec
	LogReadCount  *prometheus.CounterVec

	TotalRequests         *prometheus.CounterVec
	TotalRequestErrors    *prometheus.CounterVec
	TotalRequestsDuration *prometheus.SummaryVec
}

// NewMetricsCollector returns a new Collector.
func NewMetricsCollector() *Collector {
	// BuildInfo is a bit special as a 'metric'. It is following the guidance of
	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
	// and https://www.robustperception.io/how-to-have-labels-for-machine-roles/
	// you essentially have one const metric with a value of 1 and the labels are the strings
	// that describe the instance.
	buildInfo := prometheus.NewGauge(prometheus.GaugeOpts{
		Namespace: apiserverMetricsNamespace,
		Subsystem: apiserverSubsystemNamespace,
		Name:      "build_info",
		Help:      "The versions of various parts of the Juju Controller",
		ConstLabels: prometheus.Labels{
			MetricLabelVersion: version.Current.String(),
			"official_build":   fmt.Sprint(version.OfficialBuild),
			"go_compiler":      runtime.Compiler,
			"go_version":       runtime.Version(),
			"git_commit":       version.GitCommit,
			"git_commit_state": version.GitTreeState,
			"go_build_tags":    version.GoBuildTags,
		},
	})
	buildInfo.Set(1.0)
	return &Collector{
		TotalConnections: prometheus.NewCounter(prometheus.CounterOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "connections_total",
			Help:      "Total number of apiserver connections ever made",
		}),

		APIConnections: prometheus.NewGaugeVec(prometheus.GaugeOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "connections",
			Help:      "Current number of active apiserver connections for api handlers",
		}, MetricAPIConnectionsLabelNames),
		LoginAttempts: prometheus.NewGauge(prometheus.GaugeOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "active_login_attempts",
			Help:      "Current number of active agent login attempts",
		}),
		APIRequestDuration: prometheus.NewSummaryVec(prometheus.SummaryOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "request_duration_seconds",
			Help:      "Latency of Juju API requests in seconds.",
			Objectives: map[float64]float64{
				0.5:  0.05,
				0.9:  0.01,
				0.99: 0.001,
			},
		}, metricobserver.MetricLabelNames),

		PingFailureCount: prometheus.NewCounterVec(prometheus.CounterOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "ping_failure_count",
			Help:      "Current number of ping failures",
		}, MetricPingFailureLabelNames),

		LogWriteCount: prometheus.NewCounterVec(prometheus.CounterOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "log_write_count",
			Help:      "Current number of log writes",
		}, MetricLogLabelNames),
		LogReadCount: prometheus.NewCounterVec(prometheus.CounterOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "log_read_count",
			Help:      "Current number of log reads",
		}, MetricLogLabelNames),

		TotalRequests: prometheus.NewCounterVec(prometheus.CounterOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "outbound_requests_total",
			Help:      "Total number of http requests to outbound APIs",
		}, MetricTotalRequestsWithStatusLabelNames),
		TotalRequestErrors: prometheus.NewCounterVec(prometheus.CounterOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "outbound_request_errors_total",
			Help:      "Total number of http request errors to outbound APIs",
		}, MetricTotalRequestsLabelNames),
		TotalRequestsDuration: prometheus.NewSummaryVec(prometheus.SummaryOpts{
			Namespace: apiserverMetricsNamespace,
			Subsystem: apiserverSubsystemNamespace,
			Name:      "outbound_request_duration_seconds",
			Help:      "Latency of outbound API requests in seconds.",
			Objectives: map[float64]float64{
				0.5:  0.05,
				0.9:  0.01,
				0.99: 0.001,
			},
		}, MetricTotalRequestsLabelNames),
		BuildInfo: buildInfo,
	}
}

// Describe is part of the prometheus.Collector interface.
func (c *Collector) Describe(ch chan<- *prometheus.Desc) {
	c.TotalConnections.Describe(ch)
	c.APIConnections.Describe(ch)
	c.LoginAttempts.Describe(ch)
	c.APIRequestDuration.Describe(ch)
	c.PingFailureCount.Describe(ch)
	c.LogWriteCount.Describe(ch)
	c.LogReadCount.Describe(ch)
	c.TotalRequests.Describe(ch)
	c.TotalRequestErrors.Describe(ch)
	c.TotalRequestsDuration.Describe(ch)
	c.BuildInfo.Describe(ch)
}

// Collect is part of the prometheus.Collector interface.
func (c *Collector) Collect(ch chan<- prometheus.Metric) {
	c.TotalConnections.Collect(ch)
	c.APIConnections.Collect(ch)
	c.LoginAttempts.Collect(ch)
	c.APIRequestDuration.Collect(ch)
	c.PingFailureCount.Collect(ch)
	c.LogWriteCount.Collect(ch)
	c.LogReadCount.Collect(ch)
	c.TotalRequests.Collect(ch)
	c.TotalRequestErrors.Collect(ch)
	c.TotalRequestsDuration.Collect(ch)
	c.BuildInfo.Collect(ch)
}