package prometheus_client import ( "fmt" "log" "net/http" "regexp" "strings" "github.com/influxdata/telegraf" "github.com/influxdata/telegraf/plugins/outputs" "github.com/prometheus/client_golang/prometheus" ) var ( sanitizedChars = strings.NewReplacer("/", "_", "@", "_", " ", "_", "-", "_", ".", "_") // Prometheus metric names must match this regex // see https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels metricName = regexp.MustCompile("^[a-zA-Z_:][a-zA-Z0-9_:]*$") // Prometheus labels must match this regex // see https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels labelName = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$") ) type PrometheusClient struct { Listen string metrics map[string]*prometheus.UntypedVec } var sampleConfig = ` ## Address to listen on # listen = ":9126" ` func (p *PrometheusClient) Start() error { if p.Listen == "" { p.Listen = "localhost:9126" } http.Handle("/metrics", prometheus.Handler()) server := &http.Server{ Addr: p.Listen, } p.metrics = make(map[string]*prometheus.UntypedVec) go server.ListenAndServe() return nil } func (p *PrometheusClient) Stop() { // TODO: Use a listener for http.Server that counts active connections // that can be stopped and closed gracefully } func (p *PrometheusClient) Connect() error { // This service output does not need to make any further connections return nil } func (p *PrometheusClient) Close() error { // This service output does not need to close any of its connections return nil } func (p *PrometheusClient) SampleConfig() string { return sampleConfig } func (p *PrometheusClient) Description() string { return "Configuration for the Prometheus client to spawn" } func (p *PrometheusClient) Write(metrics []telegraf.Metric) error { if len(metrics) == 0 { return nil } for _, point := range metrics { key := point.Name() key = sanitizedChars.Replace(key) var labels []string l := prometheus.Labels{} for k, v := range point.Tags() { k = sanitizedChars.Replace(k) if len(k) == 0 { continue } if !labelName.MatchString(k) { continue } labels = append(labels, k) l[k] = v } for n, val := range point.Fields() { n = sanitizedChars.Replace(n) var mname string if n == "value" { mname = key } else { mname = fmt.Sprintf("%s_%s", key, n) } if !metricName.MatchString(mname) { continue } if _, ok := p.metrics[mname]; !ok { p.metrics[mname] = prometheus.NewUntypedVec( prometheus.UntypedOpts{ Name: mname, Help: fmt.Sprintf("Telegraf collected point '%s'", mname), }, labels, ) if err := prometheus.Register(p.metrics[mname]); err != nil { log.Printf("prometheus_client: Metric failed to register with prometheus, %s", err) continue } } switch val := val.(type) { default: log.Printf("Prometheus output, unsupported type. key: %s, type: %T\n", mname, val) case int64: m, err := p.metrics[mname].GetMetricWith(l) if err != nil { log.Printf("ERROR Getting metric in Prometheus output, "+ "key: %s, labels: %v,\nerr: %s\n", mname, l, err.Error()) continue } m.Set(float64(val)) case float64: m, err := p.metrics[mname].GetMetricWith(l) if err != nil { log.Printf("ERROR Getting metric in Prometheus output, "+ "key: %s, labels: %v,\nerr: %s\n", mname, l, err.Error()) continue } m.Set(val) } } } return nil } func init() { outputs.Add("prometheus_client", func() telegraf.Output { return &PrometheusClient{} }) }