diff --git a/metrics.go b/metrics.go index 8fc8f6e..b11e1b0 100644 --- a/metrics.go +++ b/metrics.go @@ -41,7 +41,24 @@ var defaultSet = NewSet() func WritePrometheus(w io.Writer, exposeProcessMetrics bool) { defaultSet.WritePrometheus(w) if exposeProcessMetrics { - writeGoMetrics(w) - writeProcessMetrics(w) + WriteProcessMetrics(w) } } + +// WriteProcessMetrics writes additional process metrics in Prometheus format to w. +// +// Various `go_*` and `process_*` metrics are exposed for the currently +// running process. +// +// The WriteProcessMetrics func is usually called in combination with writing Set metrics +// inside "/metrics" handler: +// +// http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) { +// mySet.WritePrometheus(w) +// metrics.WriteProcessMetrics(w) +// }) +// +func WriteProcessMetrics(w io.Writer) { + writeGoMetrics(w) + writeProcessMetrics(w) +} diff --git a/set.go b/set.go index 3b37e91..18021a4 100644 --- a/set.go +++ b/set.go @@ -438,3 +438,28 @@ func (s *Set) registerMetric(name string, m metric) { panic(fmt.Errorf("BUG: metric %q is already registered", name)) } } + +// UnregisterMetric will remove a registered metric +func (s *Set) UnregisterMetric(name string) bool { + s.mu.Lock() + nm, ok := s.m[name] + if ok { + delete(s.m, name) + for i, a := range s.a { + if a == nm { + s.a = append(s.a[:i], s.a[i+1:]...) + } + } + } + s.mu.Unlock() + return ok +} + +// ListMetricNames will return a list of all registered metrics +func (s *Set) ListMetricNames() []string { + var list []string + for name := range s.m { + list = append(list, name) + } + return list +} diff --git a/set_test.go b/set_test.go index 3187e4c..f1952d8 100644 --- a/set_test.go +++ b/set_test.go @@ -34,3 +34,61 @@ func TestNewSet(t *testing.T) { } } } + +func TestListMetricNames(t *testing.T) { + s := NewSet() + expect := []string{"cnt1", "cnt2", "cnt3"} + // Initialize a few counters + for _, n := range expect { + c := s.NewCounter(n) + c.Inc() + } + + list := s.ListMetricNames() + + if len(list) != len(expect) { + t.Fatalf("Metrics count is wrong for listing") + } + for _, e := range expect { + found := false + for _, n := range list { + if e == n { + found = true + } + } + if !found { + t.Fatalf("Metric %s not found in listing", e) + } + } +} + +func TestUnregisterMetric(t *testing.T) { + s := NewSet() + // Initialize a few counters + for i := 0; i < 5; i++ { + c := s.NewCounter(fmt.Sprintf("counter_%d", i)) + c.Inc() + } + // Unregister existing counters + ok := s.UnregisterMetric("counter_1") + if !ok { + t.Fatalf("Metric counter_1 should return true for deregistering") + } + + // Unregister twice must return false + ok = s.UnregisterMetric("counter_1") + if ok { + t.Fatalf("Metric counter_1 should not return false on unregister twice") + } + + // Validate counters are removed + ok = false + for _, n := range s.ListMetricNames() { + if n == "counter_1" { + ok = true + } + } + if ok { + t.Fatalf("Metric counter_1 and counter_3 must not be listed anymore after unregister") + } +}