Merge pull request #129 from vrischmann/prefixed-registry

Add a prefixed registry

Closes #128

registry.go

@@ -145,6 +145,58 @@ func (r *StandardRegistry) registered() map[string]interface{} {
 	return metrics
 }
 
+type PrefixedRegistry struct {
+	underlying Registry
+	prefix     string
+}
+
+func NewPrefixedRegistry(prefix string) Registry {
+	return &PrefixedRegistry{
+		underlying: NewRegistry(),
+		prefix:     prefix,
+	}
+}
+
+// Call the given function for each registered metric.
+func (r *PrefixedRegistry) Each(fn func(string, interface{})) {
+	r.underlying.Each(fn)
+}
+
+// Get the metric by the given name or nil if none is registered.
+func (r *PrefixedRegistry) Get(name string) interface{} {
+	return r.underlying.Get(name)
+}
+
+// Gets an existing metric or registers the given one.
+// The interface can be the metric to register if not found in registry,
+// or a function returning the metric for lazy instantiation.
+func (r *PrefixedRegistry) GetOrRegister(name string, metric interface{}) interface{} {
+	realName := r.prefix + name
+	return r.underlying.GetOrRegister(realName, metric)
+}
+
+// Register the given metric under the given name. The name will be prefixed.
+func (r *PrefixedRegistry) Register(name string, metric interface{}) error {
+	realName := r.prefix + name
+	return r.underlying.Register(realName, metric)
+}
+
+// Run all registered healthchecks.
+func (r *PrefixedRegistry) RunHealthchecks() {
+	r.underlying.RunHealthchecks()
+}
+
+// Unregister the metric with the given name. The name will be prefixed.
+func (r *PrefixedRegistry) Unregister(name string) {
+	realName := r.prefix + name
+	r.underlying.Unregister(realName)
+}
+
+// Unregister all metrics.  (Mostly for testing.)
+func (r *PrefixedRegistry) UnregisterAll() {
+	r.underlying.UnregisterAll()
+}
+
 var DefaultRegistry Registry = NewRegistry()
 
 // Call the given function for each registered metric.

registry_test.go

@@ -116,3 +116,50 @@ func TestRegistryGetOrRegisterWithLazyInstantiation(t *testing.T) {
 		t.Fatal(i)
 	}
 }
+
+func TestPrefixedRegistryGetOrRegister(t *testing.T) {
+	r := NewPrefixedRegistry("prefix.")
+
+	_ = r.GetOrRegister("foo", NewCounter)
+
+	r.Each(func(name string, m interface{}) {
+		if name != "prefix.foo" {
+			t.Fatal(name)
+		}
+	})
+}
+
+func TestPrefixedRegistryRegister(t *testing.T) {
+	r := NewPrefixedRegistry("prefix.")
+
+	_ = r.Register("foo", NewCounter)
+
+	r.Each(func(name string, m interface{}) {
+		if name != "prefix.foo" {
+			t.Fatal(name)
+		}
+	})
+}
+
+func TestPrefixedRegistryUnregister(t *testing.T) {
+	r := NewPrefixedRegistry("prefix.")
+
+	_ = r.Register("foo", NewCounter)
+
+	r.Each(func(name string, m interface{}) {
+		if name != "prefix.foo" {
+			t.Fatal(name)
+		}
+	})
+
+	r.Unregister("foo")
+
+	i := 0
+	r.Each(func(name string, m interface{}) {
+		i++
+	})
+
+	if i != 0 {
+		t.Fatal(i)
+	}
+}