package metrics import ( "context" "errors" "net/http" "sync" "time" "github.com/go-kit/kit/metrics" stdprometheus "github.com/prometheus/client_golang/prometheus" "github.com/prometheus/client_golang/prometheus/collectors" "github.com/prometheus/client_golang/prometheus/promhttp" "github.com/traefik/traefik/v2/pkg/config/dynamic" "github.com/traefik/traefik/v2/pkg/log" "github.com/traefik/traefik/v2/pkg/types" ) const ( // MetricNamePrefix prefix of all metric names. MetricNamePrefix = "traefik_" // server meta information. metricConfigPrefix = MetricNamePrefix + "config_" configReloadsTotalName = metricConfigPrefix + "reloads_total" configReloadsFailuresTotalName = metricConfigPrefix + "reloads_failure_total" configLastReloadSuccessName = metricConfigPrefix + "last_reload_success" configLastReloadFailureName = metricConfigPrefix + "last_reload_failure" // TLS. metricsTLSPrefix = MetricNamePrefix + "tls_" tlsCertsNotAfterTimestamp = metricsTLSPrefix + "certs_not_after" // entry point. metricEntryPointPrefix = MetricNamePrefix + "entrypoint_" entryPointReqsTotalName = metricEntryPointPrefix + "requests_total" entryPointReqsTLSTotalName = metricEntryPointPrefix + "requests_tls_total" entryPointReqDurationName = metricEntryPointPrefix + "request_duration_seconds" entryPointOpenConnsName = metricEntryPointPrefix + "open_connections" // router level. metricRouterPrefix = MetricNamePrefix + "router_" routerReqsTotalName = metricRouterPrefix + "requests_total" routerReqsTLSTotalName = metricRouterPrefix + "requests_tls_total" routerReqDurationName = metricRouterPrefix + "request_duration_seconds" routerOpenConnsName = metricRouterPrefix + "open_connections" // service level. metricServicePrefix = MetricNamePrefix + "service_" serviceReqsTotalName = metricServicePrefix + "requests_total" serviceReqsTLSTotalName = metricServicePrefix + "requests_tls_total" serviceReqDurationName = metricServicePrefix + "request_duration_seconds" serviceOpenConnsName = metricServicePrefix + "open_connections" serviceRetriesTotalName = metricServicePrefix + "retries_total" serviceServerUpName = metricServicePrefix + "server_up" ) // promState holds all metric state internally and acts as the only Collector we register for Prometheus. // // This enables control to remove metrics that belong to outdated configuration. // As an example why this is required, consider Traefik learns about a new service. // It populates the 'traefik_server_service_up' metric for it with a value of 1 (alive). // When the service is undeployed now the metric is still there in the client library // and will be returned on the metrics endpoint until Traefik would be restarted. // // To solve this problem promState keeps track of Traefik's dynamic configuration. // Metrics that "belong" to a dynamic configuration part like services or entryPoints // are removed after they were scraped at least once when the corresponding object // doesn't exist anymore. var promState = newPrometheusState() var promRegistry = stdprometheus.NewRegistry() // PrometheusHandler exposes Prometheus routes. func PrometheusHandler() http.Handler { return promhttp.HandlerFor(promRegistry, promhttp.HandlerOpts{}) } // RegisterPrometheus registers all Prometheus metrics. // It must be called only once and failing to register the metrics will lead to a panic. func RegisterPrometheus(ctx context.Context, config *types.Prometheus) Registry { standardRegistry := initStandardRegistry(config) if err := promRegistry.Register(collectors.NewProcessCollector(collectors.ProcessCollectorOpts{})); err != nil { var arErr stdprometheus.AlreadyRegisteredError if !errors.As(err, &arErr) { log.FromContext(ctx).Warn("ProcessCollector is already registered") } } if err := promRegistry.Register(collectors.NewGoCollector()); err != nil { var arErr stdprometheus.AlreadyRegisteredError if !errors.As(err, &arErr) { log.FromContext(ctx).Warn("GoCollector is already registered") } } if !registerPromState(ctx) { return nil } return standardRegistry } func initStandardRegistry(config *types.Prometheus) Registry { buckets := []float64{0.1, 0.3, 1.2, 5.0} if config.Buckets != nil { buckets = config.Buckets } configReloads := newCounterFrom(stdprometheus.CounterOpts{ Name: configReloadsTotalName, Help: "Config reloads", }, []string{}) configReloadsFailures := newCounterFrom(stdprometheus.CounterOpts{ Name: configReloadsFailuresTotalName, Help: "Config failure reloads", }, []string{}) lastConfigReloadSuccess := newGaugeFrom(stdprometheus.GaugeOpts{ Name: configLastReloadSuccessName, Help: "Last config reload success", }, []string{}) lastConfigReloadFailure := newGaugeFrom(stdprometheus.GaugeOpts{ Name: configLastReloadFailureName, Help: "Last config reload failure", }, []string{}) tlsCertsNotAfterTimestamp := newGaugeFrom(stdprometheus.GaugeOpts{ Name: tlsCertsNotAfterTimestamp, Help: "Certificate expiration timestamp", }, []string{"cn", "serial", "sans"}) promState.vectors = []vector{ configReloads.cv, configReloadsFailures.cv, lastConfigReloadSuccess.gv, lastConfigReloadFailure.gv, tlsCertsNotAfterTimestamp.gv, } reg := &standardRegistry{ epEnabled: config.AddEntryPointsLabels, routerEnabled: config.AddRoutersLabels, svcEnabled: config.AddServicesLabels, configReloadsCounter: configReloads, configReloadsFailureCounter: configReloadsFailures, lastConfigReloadSuccessGauge: lastConfigReloadSuccess, lastConfigReloadFailureGauge: lastConfigReloadFailure, tlsCertsNotAfterTimestampGauge: tlsCertsNotAfterTimestamp, } if config.AddEntryPointsLabels { entryPointReqs := newCounterFrom(stdprometheus.CounterOpts{ Name: entryPointReqsTotalName, Help: "How many HTTP requests processed on an entrypoint, partitioned by status code, protocol, and method.", }, []string{"code", "method", "protocol", "entrypoint"}) entryPointReqsTLS := newCounterFrom(stdprometheus.CounterOpts{ Name: entryPointReqsTLSTotalName, Help: "How many HTTP requests with TLS processed on an entrypoint, partitioned by TLS Version and TLS cipher Used.", }, []string{"tls_version", "tls_cipher", "entrypoint"}) entryPointReqDurations := newHistogramFrom(stdprometheus.HistogramOpts{ Name: entryPointReqDurationName, Help: "How long it took to process the request on an entrypoint, partitioned by status code, protocol, and method.", Buckets: buckets, }, []string{"code", "method", "protocol", "entrypoint"}) entryPointOpenConns := newGaugeFrom(stdprometheus.GaugeOpts{ Name: entryPointOpenConnsName, Help: "How many open connections exist on an entrypoint, partitioned by method and protocol.", }, []string{"method", "protocol", "entrypoint"}) promState.vectors = append(promState.vectors, entryPointReqs.cv, entryPointReqsTLS.cv, entryPointReqDurations.hv, entryPointOpenConns.gv, ) reg.entryPointReqsCounter = entryPointReqs reg.entryPointReqsTLSCounter = entryPointReqsTLS reg.entryPointReqDurationHistogram, _ = NewHistogramWithScale(entryPointReqDurations, time.Second) reg.entryPointOpenConnsGauge = entryPointOpenConns } if config.AddRoutersLabels { routerReqs := newCounterFrom(stdprometheus.CounterOpts{ Name: routerReqsTotalName, Help: "How many HTTP requests are processed on a router, partitioned by service, status code, protocol, and method.", }, []string{"code", "method", "protocol", "router", "service"}) routerReqsTLS := newCounterFrom(stdprometheus.CounterOpts{ Name: routerReqsTLSTotalName, Help: "How many HTTP requests with TLS are processed on a router, partitioned by service, TLS Version, and TLS cipher Used.", }, []string{"tls_version", "tls_cipher", "router", "service"}) routerReqDurations := newHistogramFrom(stdprometheus.HistogramOpts{ Name: routerReqDurationName, Help: "How long it took to process the request on a router, partitioned by service, status code, protocol, and method.", Buckets: buckets, }, []string{"code", "method", "protocol", "router", "service"}) routerOpenConns := newGaugeFrom(stdprometheus.GaugeOpts{ Name: routerOpenConnsName, Help: "How many open connections exist on a router, partitioned by service, method, and protocol.", }, []string{"method", "protocol", "router", "service"}) promState.vectors = append(promState.vectors, routerReqs.cv, routerReqsTLS.cv, routerReqDurations.hv, routerOpenConns.gv, ) reg.routerReqsCounter = routerReqs reg.routerReqsTLSCounter = routerReqsTLS reg.routerReqDurationHistogram, _ = NewHistogramWithScale(routerReqDurations, time.Second) reg.routerOpenConnsGauge = routerOpenConns } if config.AddServicesLabels { serviceReqs := newCounterFrom(stdprometheus.CounterOpts{ Name: serviceReqsTotalName, Help: "How many HTTP requests processed on a service, partitioned by status code, protocol, and method.", }, []string{"code", "method", "protocol", "service"}) serviceReqsTLS := newCounterFrom(stdprometheus.CounterOpts{ Name: serviceReqsTLSTotalName, Help: "How many HTTP requests with TLS processed on a service, partitioned by TLS version and TLS cipher.", }, []string{"tls_version", "tls_cipher", "service"}) serviceReqDurations := newHistogramFrom(stdprometheus.HistogramOpts{ Name: serviceReqDurationName, Help: "How long it took to process the request on a service, partitioned by status code, protocol, and method.", Buckets: buckets, }, []string{"code", "method", "protocol", "service"}) serviceOpenConns := newGaugeFrom(stdprometheus.GaugeOpts{ Name: serviceOpenConnsName, Help: "How many open connections exist on a service, partitioned by method and protocol.", }, []string{"method", "protocol", "service"}) serviceRetries := newCounterFrom(stdprometheus.CounterOpts{ Name: serviceRetriesTotalName, Help: "How many request retries happened on a service.", }, []string{"service"}) serviceServerUp := newGaugeFrom(stdprometheus.GaugeOpts{ Name: serviceServerUpName, Help: "service server is up, described by gauge value of 0 or 1.", }, []string{"service", "url"}) promState.vectors = append(promState.vectors, serviceReqs.cv, serviceReqsTLS.cv, serviceReqDurations.hv, serviceOpenConns.gv, serviceRetries.cv, serviceServerUp.gv, ) reg.serviceReqsCounter = serviceReqs reg.serviceReqsTLSCounter = serviceReqsTLS reg.serviceReqDurationHistogram, _ = NewHistogramWithScale(serviceReqDurations, time.Second) reg.serviceOpenConnsGauge = serviceOpenConns reg.serviceRetriesCounter = serviceRetries reg.serviceServerUpGauge = serviceServerUp } return reg } func registerPromState(ctx context.Context) bool { err := promRegistry.Register(promState) if err == nil { return true } logger := log.FromContext(ctx) var arErr stdprometheus.AlreadyRegisteredError if errors.As(err, &arErr) { logger.Debug("Prometheus collector already registered.") return true } logger.Errorf("Unable to register Traefik to Prometheus: %v", err) return false } // OnConfigurationUpdate receives the current configuration from Traefik. // It then converts the configuration to the optimized package internal format // and sets it to the promState. func OnConfigurationUpdate(conf dynamic.Configuration, entryPoints []string) { dynCfg := newDynamicConfig() for _, value := range entryPoints { dynCfg.entryPoints[value] = true } if conf.HTTP == nil { promState.SetDynamicConfig(dynCfg) return } for name := range conf.HTTP.Routers { dynCfg.routers[name] = true } for serviceName, service := range conf.HTTP.Services { dynCfg.services[serviceName] = make(map[string]bool) if service.LoadBalancer != nil { for _, server := range service.LoadBalancer.Servers { dynCfg.services[serviceName][server.URL] = true } } } promState.SetDynamicConfig(dynCfg) } func newPrometheusState() *prometheusState { return &prometheusState{ dynamicConfig: newDynamicConfig(), deletedURLs: make(map[string][]string), } } type vector interface { stdprometheus.Collector DeletePartialMatch(labels stdprometheus.Labels) int } type prometheusState struct { vectors []vector mtx sync.Mutex dynamicConfig *dynamicConfig deletedEP []string deletedRouters []string deletedServices []string deletedURLs map[string][]string } func (ps *prometheusState) SetDynamicConfig(dynamicConfig *dynamicConfig) { ps.mtx.Lock() defer ps.mtx.Unlock() for ep := range ps.dynamicConfig.entryPoints { if _, ok := dynamicConfig.entryPoints[ep]; !ok { ps.deletedEP = append(ps.deletedEP, ep) } } for router := range ps.dynamicConfig.routers { if _, ok := dynamicConfig.routers[router]; !ok { ps.deletedRouters = append(ps.deletedRouters, router) } } for service, serV := range ps.dynamicConfig.services { actualService, ok := dynamicConfig.services[service] if !ok { ps.deletedServices = append(ps.deletedServices, service) } for url := range serV { if _, ok := actualService[url]; !ok { ps.deletedURLs[service] = append(ps.deletedURLs[service], url) } } } ps.dynamicConfig = dynamicConfig } // Describe implements prometheus.Collector and simply calls // the registered describer functions. func (ps *prometheusState) Describe(ch chan<- *stdprometheus.Desc) { for _, v := range ps.vectors { v.Describe(ch) } } // Collect implements prometheus.Collector. It calls the Collect // method of all metrics it received on the collectors channel. // It's also responsible to remove metrics that belong to an outdated configuration. // The removal happens only after their Collect method was called to ensure that // also those metrics will be exported on the current scrape. func (ps *prometheusState) Collect(ch chan<- stdprometheus.Metric) { for _, v := range ps.vectors { v.Collect(ch) } ps.mtx.Lock() defer ps.mtx.Unlock() for _, ep := range ps.deletedEP { if !ps.dynamicConfig.hasEntryPoint(ep) { ps.DeletePartialMatch(map[string]string{"entrypoint": ep}) } } for _, router := range ps.deletedRouters { if !ps.dynamicConfig.hasRouter(router) { ps.DeletePartialMatch(map[string]string{"router": router}) } } for _, service := range ps.deletedServices { if !ps.dynamicConfig.hasService(service) { ps.DeletePartialMatch(map[string]string{"service": service}) } } for service, urls := range ps.deletedURLs { for _, url := range urls { if !ps.dynamicConfig.hasServerURL(service, url) { ps.DeletePartialMatch(map[string]string{"service": service, "url": url}) } } } ps.deletedEP = nil ps.deletedRouters = nil ps.deletedServices = nil ps.deletedURLs = make(map[string][]string) } // DeletePartialMatch deletes all metrics where the variable labels contain all of those passed in as labels. // The order of the labels does not matter. // It returns the number of metrics deleted. func (ps *prometheusState) DeletePartialMatch(labels stdprometheus.Labels) int { var count int for _, elem := range ps.vectors { count += elem.DeletePartialMatch(labels) } return count } func newDynamicConfig() *dynamicConfig { return &dynamicConfig{ entryPoints: make(map[string]bool), routers: make(map[string]bool), services: make(map[string]map[string]bool), } } // dynamicConfig holds the current configuration for entryPoints, services, // and server URLs in an optimized way to check for existence. This provides // a performant way to check whether the collected metrics belong to the // current configuration or to an outdated one. type dynamicConfig struct { entryPoints map[string]bool routers map[string]bool services map[string]map[string]bool } func (d *dynamicConfig) hasEntryPoint(entrypointName string) bool { _, ok := d.entryPoints[entrypointName] return ok } func (d *dynamicConfig) hasService(serviceName string) bool { _, ok := d.services[serviceName] return ok } func (d *dynamicConfig) hasRouter(routerName string) bool { _, ok := d.routers[routerName] return ok } func (d *dynamicConfig) hasServerURL(serviceName, serverURL string) bool { if service, hasService := d.services[serviceName]; hasService { _, ok := service[serverURL] return ok } return false } func newCounterFrom(opts stdprometheus.CounterOpts, labelNames []string) *counter { cv := stdprometheus.NewCounterVec(opts, labelNames) c := &counter{ name: opts.Name, cv: cv, } if len(labelNames) == 0 { c.collector = cv.WithLabelValues() c.Add(0) } return c } type counter struct { name string cv *stdprometheus.CounterVec labelNamesValues labelNamesValues collector stdprometheus.Counter } func (c *counter) With(labelValues ...string) metrics.Counter { lnv := c.labelNamesValues.With(labelValues...) return &counter{ name: c.name, cv: c.cv, labelNamesValues: lnv, collector: c.cv.With(lnv.ToLabels()), } } func (c *counter) Add(delta float64) { c.collector.Add(delta) } func (c *counter) Describe(ch chan<- *stdprometheus.Desc) { c.cv.Describe(ch) } func newGaugeFrom(opts stdprometheus.GaugeOpts, labelNames []string) *gauge { gv := stdprometheus.NewGaugeVec(opts, labelNames) g := &gauge{ name: opts.Name, gv: gv, } if len(labelNames) == 0 { g.collector = gv.WithLabelValues() g.Set(0) } return g } type gauge struct { name string gv *stdprometheus.GaugeVec labelNamesValues labelNamesValues collector stdprometheus.Gauge } func (g *gauge) With(labelValues ...string) metrics.Gauge { lnv := g.labelNamesValues.With(labelValues...) return &gauge{ name: g.name, gv: g.gv, labelNamesValues: lnv, collector: g.gv.With(lnv.ToLabels()), } } func (g *gauge) Add(delta float64) { g.collector.Add(delta) } func (g *gauge) Set(value float64) { g.collector.Set(value) } func (g *gauge) Describe(ch chan<- *stdprometheus.Desc) { g.gv.Describe(ch) } func newHistogramFrom(opts stdprometheus.HistogramOpts, labelNames []string) *histogram { hv := stdprometheus.NewHistogramVec(opts, labelNames) return &histogram{ name: opts.Name, hv: hv, } } type histogram struct { name string hv *stdprometheus.HistogramVec labelNamesValues labelNamesValues collector stdprometheus.Observer } func (h *histogram) With(labelValues ...string) metrics.Histogram { lnv := h.labelNamesValues.With(labelValues...) return &histogram{ name: h.name, hv: h.hv, labelNamesValues: lnv, collector: h.hv.With(lnv.ToLabels()), } } func (h *histogram) Observe(value float64) { h.collector.Observe(value) } func (h *histogram) Describe(ch chan<- *stdprometheus.Desc) { h.hv.Describe(ch) } // labelNamesValues is a type alias that provides validation on its With method. // Metrics may include it as a member to help them satisfy With semantics and // save some code duplication. type labelNamesValues []string // With validates the input, and returns a new aggregate labelNamesValues. func (lvs labelNamesValues) With(labelValues ...string) labelNamesValues { if len(labelValues)%2 != 0 { labelValues = append(labelValues, "unknown") } labels := make([]string, len(lvs)+len(labelValues)) n := copy(labels, lvs) copy(labels[n:], labelValues) return labels } // ToLabels is a convenience method to convert a labelNamesValues // to the native prometheus.Labels. func (lvs labelNamesValues) ToLabels() stdprometheus.Labels { labels := make(map[string]string, len(lvs)/2) for i := 0; i < len(lvs); i += 2 { labels[lvs[i]] = lvs[i+1] } return labels }