package prometheus_client import ( "context" "fmt" "log" "net/http" "os" "regexp" "sort" "strconv" "strings" "sync" "time" "github.com/influxdata/telegraf" "github.com/influxdata/telegraf/internal" "github.com/influxdata/telegraf/plugins/outputs" "github.com/prometheus/client_golang/prometheus" "github.com/prometheus/client_golang/prometheus/promhttp" ) var invalidNameCharRE = regexp.MustCompile(`[^a-zA-Z0-9_]`) // SampleID uniquely identifies a Sample type SampleID string // Sample represents the current value of a series. type Sample struct { // Labels are the Prometheus labels. Labels map[string]string // Value is the value in the Prometheus output. Only one of these will populated. Value float64 HistogramValue map[float64]uint64 SummaryValue map[float64]float64 // Histograms and Summaries need a count and a sum Count uint64 Sum float64 // Expiration is the deadline that this Sample is valid until. Expiration time.Time } // MetricFamily contains the data required to build valid prometheus Metrics. type MetricFamily struct { // Samples are the Sample belonging to this MetricFamily. Samples map[SampleID]*Sample // Need the telegraf ValueType because there isn't a Prometheus ValueType // representing Histogram or Summary TelegrafValueType telegraf.ValueType // LabelSet is the label counts for all Samples. LabelSet map[string]int } type PrometheusClient struct { Listen string ExpirationInterval internal.Duration `toml:"expiration_interval"` Path string `toml:"path"` CollectorsExclude []string `toml:"collectors_exclude"` server *http.Server sync.Mutex // fam is the non-expired MetricFamily by Prometheus metric name. fam map[string]*MetricFamily // now returns the current time. now func() time.Time } var sampleConfig = ` ## Address to listen on # listen = ":9273" ## Interval to expire metrics and not deliver to prometheus, 0 == no expiration # expiration_interval = "60s" ## Collectors to enable, valid entries are "gocollector" and "process". ## If unset, both are enabled. collectors_exclude = ["gocollector", "process"] ` func (p *PrometheusClient) Start() error { prometheus.Register(p) for _, collector := range p.CollectorsExclude { switch collector { case "gocollector": prometheus.Unregister(prometheus.NewGoCollector()) case "process": prometheus.Unregister(prometheus.NewProcessCollector(os.Getpid(), "")) default: return fmt.Errorf("unrecognized collector %s", collector) } } if p.Listen == "" { p.Listen = "localhost:9273" } if p.Path == "" { p.Path = "/metrics" } mux := http.NewServeMux() mux.Handle(p.Path, promhttp.HandlerFor( prometheus.DefaultGatherer, promhttp.HandlerOpts{ErrorHandling: promhttp.ContinueOnError})) p.server = &http.Server{ Addr: p.Listen, Handler: mux, } go func() { if err := p.server.ListenAndServe(); err != nil { if err != http.ErrServerClosed { log.Printf("E! Error creating prometheus metric endpoint, err: %s\n", err.Error()) } } }() return nil } func (p *PrometheusClient) Stop() { // plugin gets cleaned up in Close() already. } func (p *PrometheusClient) Connect() error { // This service output does not need to make any further connections return nil } func (p *PrometheusClient) Close() error { ctx, cancel := context.WithTimeout(context.Background(), time.Second*5) defer cancel() err := p.server.Shutdown(ctx) prometheus.Unregister(p) return err } func (p *PrometheusClient) SampleConfig() string { return sampleConfig } func (p *PrometheusClient) Description() string { return "Configuration for the Prometheus client to spawn" } // Implements prometheus.Collector func (p *PrometheusClient) Describe(ch chan<- *prometheus.Desc) { prometheus.NewGauge(prometheus.GaugeOpts{Name: "Dummy", Help: "Dummy"}).Describe(ch) } // Expire removes Samples that have expired. func (p *PrometheusClient) Expire() { now := p.now() for name, family := range p.fam { for key, sample := range family.Samples { if p.ExpirationInterval.Duration != 0 && now.After(sample.Expiration) { for k, _ := range sample.Labels { family.LabelSet[k]-- } delete(family.Samples, key) if len(family.Samples) == 0 { delete(p.fam, name) } } } } } // Collect implements prometheus.Collector func (p *PrometheusClient) Collect(ch chan<- prometheus.Metric) { p.Lock() defer p.Unlock() p.Expire() for name, family := range p.fam { // Get list of all labels on MetricFamily var labelNames []string for k, v := range family.LabelSet { if v > 0 { labelNames = append(labelNames, k) } } desc := prometheus.NewDesc(name, "Telegraf collected metric", labelNames, nil) for _, sample := range family.Samples { // Get labels for this sample; unset labels will be set to the // empty string var labels []string for _, label := range labelNames { v := sample.Labels[label] labels = append(labels, v) } var metric prometheus.Metric var err error switch family.TelegrafValueType { case telegraf.Summary: metric, err = prometheus.NewConstSummary(desc, sample.Count, sample.Sum, sample.SummaryValue, labels...) case telegraf.Histogram: metric, err = prometheus.NewConstHistogram(desc, sample.Count, sample.Sum, sample.HistogramValue, labels...) default: metric, err = prometheus.NewConstMetric(desc, getPromValueType(family.TelegrafValueType), sample.Value, labels...) } if err != nil { log.Printf("E! Error creating prometheus metric, "+ "key: %s, labels: %v,\nerr: %s\n", name, labels, err.Error()) } ch <- metric } } } func sanitize(value string) string { return invalidNameCharRE.ReplaceAllString(value, "_") } func getPromValueType(tt telegraf.ValueType) prometheus.ValueType { switch tt { case telegraf.Counter: return prometheus.CounterValue case telegraf.Gauge: return prometheus.GaugeValue default: return prometheus.UntypedValue } } // CreateSampleID creates a SampleID based on the tags of a telegraf.Metric. func CreateSampleID(tags map[string]string) SampleID { pairs := make([]string, 0, len(tags)) for k, v := range tags { pairs = append(pairs, fmt.Sprintf("%s=%s", k, v)) } sort.Strings(pairs) return SampleID(strings.Join(pairs, ",")) } func addSample(fam *MetricFamily, sample *Sample, sampleID SampleID) { for k, _ := range sample.Labels { fam.LabelSet[k]++ } fam.Samples[sampleID] = sample } func (p *PrometheusClient) addMetricFamily(point telegraf.Metric, sample *Sample, mname string, sampleID SampleID) { var fam *MetricFamily var ok bool if fam, ok = p.fam[mname]; !ok { fam = &MetricFamily{ Samples: make(map[SampleID]*Sample), TelegrafValueType: point.Type(), LabelSet: make(map[string]int), } p.fam[mname] = fam } addSample(fam, sample, sampleID) } func (p *PrometheusClient) Write(metrics []telegraf.Metric) error { p.Lock() defer p.Unlock() now := p.now() for _, point := range metrics { tags := point.Tags() sampleID := CreateSampleID(tags) labels := make(map[string]string) for k, v := range tags { labels[sanitize(k)] = v } // Prometheus doesn't have a string value type, so convert string // fields to labels. for fn, fv := range point.Fields() { switch fv := fv.(type) { case string: labels[sanitize(fn)] = fv } } switch point.Type() { case telegraf.Summary: var mname string var sum float64 var count uint64 summaryvalue := make(map[float64]float64) for fn, fv := range point.Fields() { var value float64 switch fv := fv.(type) { case int64: value = float64(fv) case float64: value = fv default: continue } switch fn { case "sum": sum = value case "count": count = uint64(value) default: limit, err := strconv.ParseFloat(fn, 64) if err == nil { summaryvalue[limit] = value } } } sample := &Sample{ Labels: labels, SummaryValue: summaryvalue, Count: count, Sum: sum, Expiration: now.Add(p.ExpirationInterval.Duration), } mname = sanitize(point.Name()) p.addMetricFamily(point, sample, mname, sampleID) case telegraf.Histogram: var mname string var sum float64 var count uint64 histogramvalue := make(map[float64]uint64) for fn, fv := range point.Fields() { var value float64 switch fv := fv.(type) { case int64: value = float64(fv) case float64: value = fv default: continue } switch fn { case "sum": sum = value case "count": count = uint64(value) default: limit, err := strconv.ParseFloat(fn, 64) if err == nil { histogramvalue[limit] = uint64(value) } } } sample := &Sample{ Labels: labels, HistogramValue: histogramvalue, Count: count, Sum: sum, Expiration: now.Add(p.ExpirationInterval.Duration), } mname = sanitize(point.Name()) p.addMetricFamily(point, sample, mname, sampleID) default: for fn, fv := range point.Fields() { // Ignore string and bool fields. var value float64 switch fv := fv.(type) { case int64: value = float64(fv) case float64: value = fv default: continue } sample := &Sample{ Labels: labels, Value: value, Expiration: now.Add(p.ExpirationInterval.Duration), } // Special handling of value field; supports passthrough from // the prometheus input. var mname string switch point.Type() { case telegraf.Counter: if fn == "counter" { mname = sanitize(point.Name()) } case telegraf.Gauge: if fn == "gauge" { mname = sanitize(point.Name()) } } if mname == "" { if fn == "value" { mname = sanitize(point.Name()) } else { mname = sanitize(fmt.Sprintf("%s_%s", point.Name(), fn)) } } p.addMetricFamily(point, sample, mname, sampleID) } } } return nil } func init() { outputs.Add("prometheus_client", func() telegraf.Output { return &PrometheusClient{ ExpirationInterval: internal.Duration{Duration: time.Second * 60}, fam: make(map[string]*MetricFamily), now: time.Now, } }) }