Initial add of custom prometheus metrics for the fdbkubernetesmonitor

fdbkubernetesmonitor/metrics.go

@@ -0,0 +1,140 @@
+// metrics.go
+//
+// This source file is part of the FoundationDB open source project
+//
+// Copyright 2021-2024 Apple Inc. and the FoundationDB project authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"strconv"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	// versionLabel represents the version label for the prometheus metrics.
+	versionLabel = "version"
+	// processLabel represents the process label for the prometheus metrics.
+	processLabel = "process"
+	// namespace is the prometheus namespace for the metrics
+	namespace = "fdbkubernetesmonitor"
+	// restartCountMetricName represents the name of the restart metric.
+	restartCountMetricName = "restart_count"
+	// configurationChangeCountMetricName represents the configuration_change_count metric.
+	configurationChangeCountMetricName = "configuration_change_count"
+	// lastAppliedConfigurationTimestampMetricName represents the last_applied_configuration_timestamp metric.
+	lastAppliedConfigurationTimestampMetricName = "last_applied_configuration_timestamp"
+	// startTimestampMetricName represents the start_timestamp metric.
+	startTimestampMetricName = "start_timestamp"
+	// runningVersionMetricName represents the running_version metric.
+	runningVersionMetricName = "running_version"
+	// desiredVersionMetricName represents the desired_version metric.
+	desiredVersionMetricName = "desired_version"
+)
+
+// metrics represents the custom prometheus metrics for the Monitor.
+type metrics struct {
+	// restartCount represents the total number of fdbserver process restarts.
+	restartCount *prometheus.CounterVec
+	// configurationChangeCount represents the total number of observed configuration changes.
+	configurationChangeCount prometheus.Counter
+	// lastAppliedConfigurationTimestamp provides a unix timestamp when the last configuration was applied.
+	lastAppliedConfigurationTimestamp prometheus.Gauge
+	// startTimestamp represents the timestamp when a specific process was started.
+	startTimestamp *prometheus.GaugeVec
+	// runningVersion represents the current running version of the binaries.
+	runningVersion *prometheus.GaugeVec
+	// desiredVersion represents the desired running version of the binaries.
+	desiredVersion *prometheus.GaugeVec
+	// previousDesiredVersion keeps the previous seen desired version.
+	previousDesiredVersion string
+	// previousRunningVersion keeps the prvious seen running version.
+	previousRunningVersion string
+}
+
+// registerConfigurationChange will update the current prometheus metrics related to configuration changes.
+// This method doesn't use latch as it will only be called from acceptConfiguration which already uses a mutex.
+func (metrics *metrics) registerConfigurationChange(version string) {
+	// Update the prometheus metrics.
+	metrics.lastAppliedConfigurationTimestamp.SetToCurrentTime()
+	metrics.configurationChangeCount.Inc()
+	// Update the desired version for the fdbserver process.
+	metrics.desiredVersion.With(prometheus.Labels{versionLabel: version}).Set(1.0)
+	// If we had a different desired version before we want to make sure to reset this value.
+	if metrics.previousDesiredVersion != "" && metrics.previousDesiredVersion != version {
+		metrics.desiredVersion.With(prometheus.Labels{versionLabel: metrics.previousDesiredVersion}).Set(0.0)
+	}
+	metrics.previousDesiredVersion = version
+}
+
+// registerProcessStartup will update the current prometheus metrics related to process startup and running versions.
+func (metrics *metrics) registerProcessStartup(processNumber int, version string) {
+	castedProcessNumber := strconv.Itoa(processNumber)
+	metrics.restartCount.With(prometheus.Labels{processLabel: castedProcessNumber}).Inc()
+	metrics.startTimestamp.With(prometheus.Labels{processLabel: castedProcessNumber}).SetToCurrentTime()
+	metrics.runningVersion.With(prometheus.Labels{versionLabel: version}).Set(1.0)
+	// If we had a different desired version before we want to make sure to reset this value.
+	if metrics.previousRunningVersion != "" && metrics.previousRunningVersion != version {
+		metrics.runningVersion.With(prometheus.Labels{versionLabel: metrics.previousRunningVersion}).Set(0.0)
+	}
+	metrics.previousRunningVersion = version
+}
+
+// registerMetrics will register the monitor metrics and returns a metrics struct to update the current metrics.
+func registerMetrics(reg prometheus.Registerer) *metrics {
+	monitorMetrics := &metrics{
+		restartCount: prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Namespace: namespace,
+				Name:      restartCountMetricName,
+				Help:      "Number of fdbserver process restarts in total.",
+			}, []string{processLabel}),
+		configurationChangeCount: prometheus.NewCounter(prometheus.CounterOpts{
+			Namespace: namespace,
+			Name:      configurationChangeCountMetricName,
+			Help:      "Number of observed configuration changes.",
+		}),
+		lastAppliedConfigurationTimestamp: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Name:      lastAppliedConfigurationTimestampMetricName,
+			Help:      "Timestamp when the last time the configuration was applied.",
+		}),
+		startTimestamp: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Name:      startTimestampMetricName,
+			Help:      "Timestamp when the last time the configuration was applied.",
+		}, []string{processLabel}),
+		runningVersion: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Name:      runningVersionMetricName,
+			Help:      "The current running version of the fdbserver processes started by this monitor.",
+		}, []string{versionLabel}),
+		desiredVersion: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Name:      desiredVersionMetricName,
+			Help:      "The desired running version of the fdbserver processes started by this monitor.",
+		}, []string{versionLabel}),
+	}
+
+	reg.MustRegister(monitorMetrics.restartCount)
+	reg.MustRegister(monitorMetrics.configurationChangeCount)
+	reg.MustRegister(monitorMetrics.lastAppliedConfigurationTimestamp)
+	reg.MustRegister(monitorMetrics.startTimestamp)
+	reg.MustRegister(monitorMetrics.runningVersion)
+	reg.MustRegister(monitorMetrics.desiredVersion)
+
+	return monitorMetrics
+}