metrics: pull library and introduce ResettingTimer and InfluxDB reporter (#15910)

* go-metrics: fork library and introduce ResettingTimer and InfluxDB reporter.

* vendor: change nonsense/go-metrics to ethersphere/go-metrics

* go-metrics: add tests. move ResettingTimer logic from reporter to type.

* all, metrics: pull in metrics package in go-ethereum

* metrics/test: make sure metrics are enabled for tests

* metrics: apply gosimple rules

* metrics/exp, internal/debug: init expvar endpoint when starting pprof server

* internal/debug: tiny comment formatting fix

1 files changed, 305 insertions, 0 deletions

diff --git a/metrics/registry_test.go b/metrics/registry_test.go
new file mode 100644
index 000000000..a63e485fe
--- /dev/null
+++ b/metrics/registry_test.go
@@ -0,0 +1,305 @@
+package metrics
+
+import (
+	"testing"
+)
+
+func BenchmarkRegistry(b *testing.B) {
+	r := NewRegistry()
+	r.Register("foo", NewCounter())
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		r.Each(func(string, interface{}) {})
+	}
+}
+
+func TestRegistry(t *testing.T) {
+	r := NewRegistry()
+	r.Register("foo", NewCounter())
+	i := 0
+	r.Each(func(name string, iface interface{}) {
+		i++
+		if "foo" != name {
+			t.Fatal(name)
+		}
+		if _, ok := iface.(Counter); !ok {
+			t.Fatal(iface)
+		}
+	})
+	if 1 != i {
+		t.Fatal(i)
+	}
+	r.Unregister("foo")
+	i = 0
+	r.Each(func(string, interface{}) { i++ })
+	if 0 != i {
+		t.Fatal(i)
+	}
+}
+
+func TestRegistryDuplicate(t *testing.T) {
+	r := NewRegistry()
+	if err := r.Register("foo", NewCounter()); nil != err {
+		t.Fatal(err)
+	}
+	if err := r.Register("foo", NewGauge()); nil == err {
+		t.Fatal(err)
+	}
+	i := 0
+	r.Each(func(name string, iface interface{}) {
+		i++
+		if _, ok := iface.(Counter); !ok {
+			t.Fatal(iface)
+		}
+	})
+	if 1 != i {
+		t.Fatal(i)
+	}
+}
+
+func TestRegistryGet(t *testing.T) {
+	r := NewRegistry()
+	r.Register("foo", NewCounter())
+	if count := r.Get("foo").(Counter).Count(); 0 != count {
+		t.Fatal(count)
+	}
+	r.Get("foo").(Counter).Inc(1)
+	if count := r.Get("foo").(Counter).Count(); 1 != count {
+		t.Fatal(count)
+	}
+}
+
+func TestRegistryGetOrRegister(t *testing.T) {
+	r := NewRegistry()
+
+	// First metric wins with GetOrRegister
+	_ = r.GetOrRegister("foo", NewCounter())
+	m := r.GetOrRegister("foo", NewGauge())
+	if _, ok := m.(Counter); !ok {
+		t.Fatal(m)
+	}
+
+	i := 0
+	r.Each(func(name string, iface interface{}) {
+		i++
+		if name != "foo" {
+			t.Fatal(name)
+		}
+		if _, ok := iface.(Counter); !ok {
+			t.Fatal(iface)
+		}
+	})
+	if i != 1 {
+		t.Fatal(i)
+	}
+}
+
+func TestRegistryGetOrRegisterWithLazyInstantiation(t *testing.T) {
+	r := NewRegistry()
+
+	// First metric wins with GetOrRegister
+	_ = r.GetOrRegister("foo", NewCounter)
+	m := r.GetOrRegister("foo", NewGauge)
+	if _, ok := m.(Counter); !ok {
+		t.Fatal(m)
+	}
+
+	i := 0
+	r.Each(func(name string, iface interface{}) {
+		i++
+		if name != "foo" {
+			t.Fatal(name)
+		}
+		if _, ok := iface.(Counter); !ok {
+			t.Fatal(iface)
+		}
+	})
+	if i != 1 {
+		t.Fatal(i)
+	}
+}
+
+func TestRegistryUnregister(t *testing.T) {
+	l := len(arbiter.meters)
+	r := NewRegistry()
+	r.Register("foo", NewCounter())
+	r.Register("bar", NewMeter())
+	r.Register("baz", NewTimer())
+	if len(arbiter.meters) != l+2 {
+		t.Errorf("arbiter.meters: %d != %d\n", l+2, len(arbiter.meters))
+	}
+	r.Unregister("foo")
+	r.Unregister("bar")
+	r.Unregister("baz")
+	if len(arbiter.meters) != l {
+		t.Errorf("arbiter.meters: %d != %d\n", l+2, len(arbiter.meters))
+	}
+}
+
+func TestPrefixedChildRegistryGetOrRegister(t *testing.T) {
+	r := NewRegistry()
+	pr := NewPrefixedChildRegistry(r, "prefix.")
+
+	_ = pr.GetOrRegister("foo", NewCounter())
+
+	i := 0
+	r.Each(func(name string, m interface{}) {
+		i++
+		if name != "prefix.foo" {
+			t.Fatal(name)
+		}
+	})
+	if i != 1 {
+		t.Fatal(i)
+	}
+}
+
+func TestPrefixedRegistryGetOrRegister(t *testing.T) {
+	r := NewPrefixedRegistry("prefix.")
+
+	_ = r.GetOrRegister("foo", NewCounter())
+
+	i := 0
+	r.Each(func(name string, m interface{}) {
+		i++
+		if name != "prefix.foo" {
+			t.Fatal(name)
+		}
+	})
+	if i != 1 {
+		t.Fatal(i)
+	}
+}
+
+func TestPrefixedRegistryRegister(t *testing.T) {
+	r := NewPrefixedRegistry("prefix.")
+	err := r.Register("foo", NewCounter())
+	c := NewCounter()
+	Register("bar", c)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	i := 0
+	r.Each(func(name string, m interface{}) {
+		i++
+		if name != "prefix.foo" {
+			t.Fatal(name)
+		}
+	})
+	if i != 1 {
+		t.Fatal(i)
+	}
+}
+
+func TestPrefixedRegistryUnregister(t *testing.T) {
+	r := NewPrefixedRegistry("prefix.")
+
+	_ = r.Register("foo", NewCounter())
+
+	i := 0
+	r.Each(func(name string, m interface{}) {
+		i++
+		if name != "prefix.foo" {
+			t.Fatal(name)
+		}
+	})
+	if i != 1 {
+		t.Fatal(i)
+	}
+
+	r.Unregister("foo")
+
+	i = 0
+	r.Each(func(name string, m interface{}) {
+		i++
+	})
+
+	if i != 0 {
+		t.Fatal(i)
+	}
+}
+
+func TestPrefixedRegistryGet(t *testing.T) {
+	pr := NewPrefixedRegistry("prefix.")
+	name := "foo"
+	pr.Register(name, NewCounter())
+
+	fooCounter := pr.Get(name)
+	if fooCounter == nil {
+		t.Fatal(name)
+	}
+}
+
+func TestPrefixedChildRegistryGet(t *testing.T) {
+	r := NewRegistry()
+	pr := NewPrefixedChildRegistry(r, "prefix.")
+	name := "foo"
+	pr.Register(name, NewCounter())
+	fooCounter := pr.Get(name)
+	if fooCounter == nil {
+		t.Fatal(name)
+	}
+}
+
+func TestChildPrefixedRegistryRegister(t *testing.T) {
+	r := NewPrefixedChildRegistry(DefaultRegistry, "prefix.")
+	err := r.Register("foo", NewCounter())
+	c := NewCounter()
+	Register("bar", c)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	i := 0
+	r.Each(func(name string, m interface{}) {
+		i++
+		if name != "prefix.foo" {
+			t.Fatal(name)
+		}
+	})
+	if i != 1 {
+		t.Fatal(i)
+	}
+}
+
+func TestChildPrefixedRegistryOfChildRegister(t *testing.T) {
+	r := NewPrefixedChildRegistry(NewRegistry(), "prefix.")
+	r2 := NewPrefixedChildRegistry(r, "prefix2.")
+	err := r.Register("foo2", NewCounter())
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	err = r2.Register("baz", NewCounter())
+	c := NewCounter()
+	Register("bars", c)
+
+	i := 0
+	r2.Each(func(name string, m interface{}) {
+		i++
+		if name != "prefix.prefix2.baz" {
+			//t.Fatal(name)
+		}
+	})
+	if i != 1 {
+		t.Fatal(i)
+	}
+}
+
+func TestWalkRegistries(t *testing.T) {
+	r := NewPrefixedChildRegistry(NewRegistry(), "prefix.")
+	r2 := NewPrefixedChildRegistry(r, "prefix2.")
+	err := r.Register("foo2", NewCounter())
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	err = r2.Register("baz", NewCounter())
+	c := NewCounter()
+	Register("bars", c)
+
+	_, prefix := findPrefix(r2, "")
+	if "prefix.prefix2." != prefix {
+		t.Fatal(prefix)
+	}
+
+}