package metrics import ( "net/http" "sort" "strings" "sync" "github.com/containous/mux" "github.com/containous/traefik/safe" "github.com/containous/traefik/types" "github.com/go-kit/kit/metrics" stdprometheus "github.com/prometheus/client_golang/prometheus" "github.com/prometheus/client_golang/prometheus/promhttp" ) const ( metricNamePrefix = "traefik_" // server meta information configReloadsTotalName = metricNamePrefix + "config_reloads_total" configReloadsFailuresTotalName = metricNamePrefix + "config_reloads_failure_total" configLastReloadSuccessName = metricNamePrefix + "config_last_reload_success" configLastReloadFailureName = metricNamePrefix + "config_last_reload_failure" // entrypoint entrypointReqsTotalName = metricNamePrefix + "entrypoint_requests_total" entrypointReqDurationName = metricNamePrefix + "entrypoint_request_duration_seconds" entrypointOpenConnsName = metricNamePrefix + "entrypoint_open_connections" // backend level backendReqsTotalName = metricNamePrefix + "backend_requests_total" backendReqDurationName = metricNamePrefix + "backend_request_duration_seconds" backendOpenConnsName = metricNamePrefix + "backend_open_connections" backendRetriesTotalName = metricNamePrefix + "backend_retries_total" backendServerUpName = metricNamePrefix + "backend_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 // // This enables control to remove metrics that belong to outdated configuration.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_backend_up' metric for it with a value of 1 (alive). // When the backend 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 backends or entrypoints // are removed after they were scraped at least once when the corresponding object // doesn't exist anymore. var promState = newPrometheusState() // PrometheusHandler exposes Prometheus routes. type PrometheusHandler struct{} // AddRoutes adds Prometheus routes on a router. func (h PrometheusHandler) AddRoutes(router *mux.Router) { router.Methods(http.MethodGet).Path("/metrics").Handler(promhttp.Handler()) } // RegisterPrometheus registers all Prometheus metrics. // It must be called only once and failing to register the metrics will lead to a panic. func RegisterPrometheus(config *types.Prometheus) Registry { buckets := []float64{0.1, 0.3, 1.2, 5.0} if config.Buckets != nil { buckets = config.Buckets } safe.Go(func() { promState.ListenValueUpdates() }) configReloads := newCounterFrom(promState.collectors, stdprometheus.CounterOpts{ Name: configReloadsTotalName, Help: "Config reloads", }, []string{}) configReloadsFailures := newCounterFrom(promState.collectors, stdprometheus.CounterOpts{ Name: configReloadsFailuresTotalName, Help: "Config failure reloads", }, []string{}) lastConfigReloadSuccess := newGaugeFrom(promState.collectors, stdprometheus.GaugeOpts{ Name: configLastReloadSuccessName, Help: "Last config reload success", }, []string{}) lastConfigReloadFailure := newGaugeFrom(promState.collectors, stdprometheus.GaugeOpts{ Name: configLastReloadFailureName, Help: "Last config reload failure", }, []string{}) entrypointReqs := newCounterFrom(promState.collectors, 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"}) entrypointReqDurations := newHistogramFrom(promState.collectors, 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(promState.collectors, stdprometheus.GaugeOpts{ Name: entrypointOpenConnsName, Help: "How many open connections exist on an entrypoint, partitioned by method and protocol.", }, []string{"method", "protocol", "entrypoint"}) backendReqs := newCounterFrom(promState.collectors, stdprometheus.CounterOpts{ Name: backendReqsTotalName, Help: "How many HTTP requests processed on a backend, partitioned by status code, protocol, and method.", }, []string{"code", "method", "protocol", "backend"}) backendReqDurations := newHistogramFrom(promState.collectors, stdprometheus.HistogramOpts{ Name: backendReqDurationName, Help: "How long it took to process the request on a backend, partitioned by status code, protocol, and method.", Buckets: buckets, }, []string{"code", "method", "protocol", "backend"}) backendOpenConns := newGaugeFrom(promState.collectors, stdprometheus.GaugeOpts{ Name: backendOpenConnsName, Help: "How many open connections exist on a backend, partitioned by method and protocol.", }, []string{"method", "protocol", "backend"}) backendRetries := newCounterFrom(promState.collectors, stdprometheus.CounterOpts{ Name: backendRetriesTotalName, Help: "How many request retries happened on a backend.", }, []string{"backend"}) backendServerUp := newGaugeFrom(promState.collectors, stdprometheus.GaugeOpts{ Name: backendServerUpName, Help: "Backend server is up, described by gauge value of 0 or 1.", }, []string{"backend", "url"}) promState.describers = []func(chan<- *stdprometheus.Desc){ configReloads.cv.Describe, configReloadsFailures.cv.Describe, lastConfigReloadSuccess.gv.Describe, lastConfigReloadFailure.gv.Describe, entrypointReqs.cv.Describe, entrypointReqDurations.hv.Describe, entrypointOpenConns.gv.Describe, backendReqs.cv.Describe, backendReqDurations.hv.Describe, backendOpenConns.gv.Describe, backendRetries.cv.Describe, backendServerUp.gv.Describe, } stdprometheus.MustRegister(promState) return &standardRegistry{ enabled: true, configReloadsCounter: configReloads, configReloadsFailureCounter: configReloadsFailures, lastConfigReloadSuccessGauge: lastConfigReloadSuccess, lastConfigReloadFailureGauge: lastConfigReloadFailure, entrypointReqsCounter: entrypointReqs, entrypointReqDurationHistogram: entrypointReqDurations, entrypointOpenConnsGauge: entrypointOpenConns, backendReqsCounter: backendReqs, backendReqDurationHistogram: backendReqDurations, backendOpenConnsGauge: backendOpenConns, backendRetriesCounter: backendRetries, backendServerUpGauge: backendServerUp, } } // 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(configurations types.Configurations) { dynamicConfig := newDynamicConfig() for _, config := range configurations { for _, frontend := range config.Frontends { for _, entrypointName := range frontend.EntryPoints { dynamicConfig.entrypoints[entrypointName] = true } } for backendName, backend := range config.Backends { dynamicConfig.backends[backendName] = make(map[string]bool) for _, server := range backend.Servers { dynamicConfig.backends[backendName][server.URL] = true } } } promState.SetDynamicConfig(dynamicConfig) } func newPrometheusState() *prometheusState { return &prometheusState{ collectors: make(chan *collector), dynamicConfig: newDynamicConfig(), state: make(map[string]*collector), } } type prometheusState struct { collectors chan *collector describers []func(ch chan<- *stdprometheus.Desc) mtx sync.Mutex dynamicConfig *dynamicConfig state map[string]*collector } func (ps *prometheusState) SetDynamicConfig(dynamicConfig *dynamicConfig) { ps.mtx.Lock() defer ps.mtx.Unlock() ps.dynamicConfig = dynamicConfig } func (ps *prometheusState) ListenValueUpdates() { for collector := range ps.collectors { ps.mtx.Lock() ps.state[collector.id] = collector ps.mtx.Unlock() } } // Describe implements prometheus.Collector and simply calls // the registered describer functions. func (ps *prometheusState) Describe(ch chan<- *stdprometheus.Desc) { for _, desc := range ps.describers { desc(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) { ps.mtx.Lock() defer ps.mtx.Unlock() var outdatedKeys []string for key, cs := range ps.state { cs.collector.Collect(ch) if ps.isOutdated(cs) { outdatedKeys = append(outdatedKeys, key) } } for _, key := range outdatedKeys { ps.state[key].delete() delete(ps.state, key) } } // isOutdated checks whether the passed collector has labels that mark // it as belonging to an outdated configuration of Traefik. func (ps *prometheusState) isOutdated(collector *collector) bool { labels := collector.labels if entrypointName, ok := labels["entrypoint"]; ok && !ps.dynamicConfig.hasEntrypoint(entrypointName) { return true } if backendName, ok := labels["backend"]; ok { if !ps.dynamicConfig.hasBackend(backendName) { return true } if url, ok := labels["url"]; ok && !ps.dynamicConfig.hasServerURL(backendName, url) { return true } } return false } func newDynamicConfig() *dynamicConfig { return &dynamicConfig{ entrypoints: make(map[string]bool), backends: make(map[string]map[string]bool), } } // dynamicConfig holds the current configuration for entrypoints, backends, // 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 backends map[string]map[string]bool } func (d *dynamicConfig) hasEntrypoint(entrypointName string) bool { _, ok := d.entrypoints[entrypointName] return ok } func (d *dynamicConfig) hasBackend(backendName string) bool { _, ok := d.backends[backendName] return ok } func (d *dynamicConfig) hasServerURL(backendName, serverURL string) bool { if backend, hasBackend := d.backends[backendName]; hasBackend { _, ok := backend[serverURL] return ok } return false } func newCollector(metricName string, labels stdprometheus.Labels, c stdprometheus.Collector, delete func()) *collector { return &collector{ id: buildMetricID(metricName, labels), labels: labels, collector: c, delete: delete, } } // collector wraps a Collector object from the Prometheus client library. // It adds information on how many generations this metric should be present // in the /metrics output, relatived to the time it was last tracked. type collector struct { id string labels stdprometheus.Labels collector stdprometheus.Collector delete func() } func buildMetricID(metricName string, labels stdprometheus.Labels) string { var labelNamesValues []string for name, value := range labels { labelNamesValues = append(labelNamesValues, name, value) } sort.Strings(labelNamesValues) return metricName + ":" + strings.Join(labelNamesValues, "|") } func newCounterFrom(collectors chan<- *collector, opts stdprometheus.CounterOpts, labelNames []string) *counter { cv := stdprometheus.NewCounterVec(opts, labelNames) c := &counter{ name: opts.Name, cv: cv, collectors: collectors, } if len(labelNames) == 0 { c.Add(0) } return c } type counter struct { name string cv *stdprometheus.CounterVec labelNamesValues labelNamesValues collectors chan<- *collector } func (c *counter) With(labelValues ...string) metrics.Counter { return &counter{ name: c.name, cv: c.cv, labelNamesValues: c.labelNamesValues.With(labelValues...), collectors: c.collectors, } } func (c *counter) Add(delta float64) { labels := c.labelNamesValues.ToLabels() collector := c.cv.With(labels) collector.Add(delta) c.collectors <- newCollector(c.name, labels, collector, func() { c.cv.Delete(labels) }) } func (c *counter) Describe(ch chan<- *stdprometheus.Desc) { c.cv.Describe(ch) } func newGaugeFrom(collectors chan<- *collector, opts stdprometheus.GaugeOpts, labelNames []string) *gauge { gv := stdprometheus.NewGaugeVec(opts, labelNames) g := &gauge{ name: opts.Name, gv: gv, collectors: collectors, } if len(labelNames) == 0 { g.Set(0) } return g } type gauge struct { name string gv *stdprometheus.GaugeVec labelNamesValues labelNamesValues collectors chan<- *collector } func (g *gauge) With(labelValues ...string) metrics.Gauge { return &gauge{ name: g.name, gv: g.gv, labelNamesValues: g.labelNamesValues.With(labelValues...), collectors: g.collectors, } } func (g *gauge) Add(delta float64) { labels := g.labelNamesValues.ToLabels() collector := g.gv.With(labels) collector.Add(delta) g.collectors <- newCollector(g.name, labels, collector, func() { g.gv.Delete(labels) }) } func (g *gauge) Set(value float64) { labels := g.labelNamesValues.ToLabels() collector := g.gv.With(labels) collector.Set(value) g.collectors <- newCollector(g.name, labels, collector, func() { g.gv.Delete(labels) }) } func (g *gauge) Describe(ch chan<- *stdprometheus.Desc) { g.gv.Describe(ch) } func newHistogramFrom(collectors chan<- *collector, opts stdprometheus.HistogramOpts, labelNames []string) *histogram { hv := stdprometheus.NewHistogramVec(opts, labelNames) return &histogram{ name: opts.Name, hv: hv, collectors: collectors, } } type histogram struct { name string hv *stdprometheus.HistogramVec labelNamesValues labelNamesValues collectors chan<- *collector } func (h *histogram) With(labelValues ...string) metrics.Histogram { return &histogram{ name: h.name, hv: h.hv, labelNamesValues: h.labelNamesValues.With(labelValues...), collectors: h.collectors, } } func (h *histogram) Observe(value float64) { labels := h.labelNamesValues.ToLabels() collector := h.hv.With(labels) collector.Observe(value) h.collectors <- newCollector(h.name, labels, collector, func() { h.hv.Delete(labels) }) } 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") } return append(lvs, labelValues...) } // ToLabels is a convenience method to convert a labelNamesValues // to the native prometheus.Labels. func (lvs labelNamesValues) ToLabels() stdprometheus.Labels { labels := stdprometheus.Labels{} for i := 0; i < len(lvs); i += 2 { labels[lvs[i]] = lvs[i+1] } return labels }