initial commit

collector/executor.go

@@ -0,0 +1,73 @@
+package collector
+
+import (
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// NsqExecutor collects all NSQ metrics from the registered collectors.
+// This type implements the prometheus.Collector interface and can be
+// registered in the metrics collection.
+//
+// The executor takes the time needed by each registered collector and
+// provides an extra metric for this. This metric is labeled with the
+// result ("success" or "error") and the collector.
+type NsqExecutor struct {
+	collectors map[string]Collector
+	summary    *prometheus.SummaryVec
+}
+
+// NewNsqExecutor creates a new executor for the NSQ metrics.
+func NewNsqExecutor(namespace string) *NsqExecutor {
+	return &NsqExecutor{
+		collectors: make(map[string]Collector),
+		summary: prometheus.NewSummaryVec(prometheus.SummaryOpts{
+			Namespace: namespace,
+			Subsystem: "exporter",
+			Name:      "scape_duration_seconds",
+			Help:      "Duration of a scrape job of the NSQ exporter",
+		}, []string{"collector", "result"}),
+	}
+}
+
+// AddCollector adds a new collector for the metrics collection.
+// Each collector needs a unique name which is used as a label
+// for the executor metric.
+func (e *NsqExecutor) AddCollector(name string, c Collector) {
+	e.collectors[name] = c
+}
+
+// Describe implements the prometheus.Collector interface.
+func (e *NsqExecutor) Describe(out chan<- *prometheus.Desc) {
+	e.summary.Describe(out)
+}
+
+// Collect implements the prometheus.Collector interface.
+func (e *NsqExecutor) Collect(out chan<- prometheus.Metric) {
+	var wg sync.WaitGroup
+	wg.Add(len(e.collectors))
+	for name, coll := range e.collectors {
+		go func(name string, coll Collector) {
+			e.exec(name, coll, out)
+			wg.Done()
+		}(name, coll)
+	}
+	wg.Wait()
+}
+
+func (e *NsqExecutor) exec(name string, coll Collector, out chan<- prometheus.Metric) {
+	start := time.Now()
+	err := coll.Collect(out)
+	dur := time.Since(start)
+
+	labels := prometheus.Labels{"collector": name}
+	if err != nil {
+		labels["result"] = "error"
+	} else {
+		labels["result"] = "success"
+	}
+
+	e.summary.With(labels).Observe(dur.Seconds())
+}