package prometheus_client import ( "context" "fmt" "log" "net/http" "regexp" "sort" "strings" "sync" "time" "github.com/influxdata/telegraf" "github.com/influxdata/telegraf/internal" "github.com/influxdata/telegraf/plugins/outputs" "github.com/prometheus/client_golang/prometheus" ) 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. Value 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 // Type of the Value. ValueType prometheus.ValueType // LabelSet is the label counts for all Samples. LabelSet map[string]int } type PrometheusClient struct { Listen string ExpirationInterval internal.Duration `toml:"expiration_interval"` 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 = ":9126" ## Interval to expire metrics and not deliver to prometheus, 0 == no expiration # expiration_interval = "60s" ` func (p *PrometheusClient) Start() error { prometheus.Register(p) if p.Listen == "" { p.Listen = "localhost:9126" } mux := http.NewServeMux() mux.Handle("/metrics", prometheus.Handler()) p.server = &http.Server{ Addr: p.Listen, Handler: mux, } go p.server.ListenAndServe() 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() return p.server.Shutdown(ctx) } 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) } metric, err := prometheus.NewConstMetric(desc, family.ValueType, 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 valueType(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 (p *PrometheusClient) Write(metrics []telegraf.Metric) error { p.Lock() defer p.Unlock() now := p.now() for _, point := range metrics { tags := point.Tags() vt := valueType(point.Type()) sampleID := CreateSampleID(tags) labels := make(map[string]string) for k, v := range tags { labels[sanitize(k)] = v } 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 if fn == "value" { mname = sanitize(point.Name()) } else { mname = sanitize(fmt.Sprintf("%s_%s", point.Name(), fn)) } var fam *MetricFamily var ok bool if fam, ok = p.fam[mname]; !ok { fam = &MetricFamily{ Samples: make(map[SampleID]*Sample), ValueType: vt, LabelSet: make(map[string]int), } p.fam[mname] = fam } else { if fam.ValueType != vt { // Don't return an error since this would be a permanent error log.Printf("Mixed ValueType for measurement %q; dropping point", point.Name()) break } } for k, _ := range sample.Labels { fam.LabelSet[k]++ } fam.Samples[sampleID] = sample } } 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, } }) }