add Clock to Registry (#79)

spectator/registry.go

@@ -11,7 +11,7 @@ import (
 	"github.com/Netflix/spectator-go/spectator/logger"
 	"github.com/Netflix/spectator-go/spectator/meter"
 	"github.com/Netflix/spectator-go/spectator/writer"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"time"
 )
@@ -24,6 +24,7 @@ type Meter interface {
 type RegistryInterface interface {
 	GetLogger() logger.Logger
 	SetLogger(logger logger.Logger)
+	Clock() Clock
 	NewId(name string, tags map[string]string) *meter.Id
 	Counter(name string, tags map[string]string) *meter.Counter
 	CounterWithId(id *meter.Id) *meter.Counter
@@ -53,6 +54,7 @@ var _ RegistryInterface = (*Registry)(nil)
 
 // Registry is the collection of meters being reported.
 type Registry struct {
+	clock  Clock
 	config *Config
 	writer writer.Writer
 }
@@ -61,7 +63,7 @@ type Registry struct {
 func NewRegistryConfiguredBy(filePath string) (*Registry, error) {
 	path := filepath.Clean(filePath)
 	/* #nosec G304 */
-	bytes, err := ioutil.ReadFile(path)
+	bytes, err := os.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}
@@ -103,13 +105,22 @@ func NewRegistry(config *Config) (*Registry, error) {
 	config.Log.Infof("Initializing Registry using writer: %T", newWriter)
 
 	r := &Registry{
+		clock:  &SystemClock{},
 		config: config,
 		writer: newWriter,
 	}
 
 	return r, nil
 }
 
+// NewRegistryWithClock returns a new registry with the clock overridden to the
+// one injected here. This function is mostly used for testing.
+func NewRegistryWithClock(config *Config, clock Clock) *Registry {
+	r, _ := NewRegistry(config)
+	r.clock = clock
+	return r
+}
+
 // GetLogger returns the internal logger.
 func (r *Registry) GetLogger() logger.Logger {
 	return r.config.Log
@@ -119,6 +130,10 @@ func (r *Registry) SetLogger(logger logger.Logger) {
 	r.config.Log = logger
 }
 
+func (r *Registry) Clock() Clock {
+	return r.clock
+}
+
 // NewId calls meters.NewId() and adds the CommonTags registered in the config.
 func (r *Registry) NewId(name string, tags map[string]string) *meter.Id {
 	newId := meter.NewId(name, tags)

spectator/registry_test.go

@@ -7,6 +7,17 @@ import (
 	"time"
 )
 
+func TestRegistry_Clock(t *testing.T) {
+	mw := &writer.MemoryWriter{}
+	clock := &ManualClock{1}
+	r := NewTestRegistryWithClock(mw, clock)
+	now := r.Clock().Now()
+	expected := time.Unix(0, 1)
+	if now != expected {
+		t.Errorf("Expected '%+v', got '%+v'", expected, now)
+	}
+}
+
 func TestRegistryWithMemoryWriter_Counter(t *testing.T) {
 	mw := &writer.MemoryWriter{}
 	r := NewTestRegistry(mw)
@@ -131,7 +142,16 @@ func TestRegistryWithMemoryWriter_PercentileTimer(t *testing.T) {
 
 func NewTestRegistry(mw *writer.MemoryWriter) *Registry {
 	return &Registry{
+		clock:  &SystemClock{},
+		config: &Config{},
 		writer: mw,
+	}
+}
+
+func NewTestRegistryWithClock(mw *writer.MemoryWriter, clock Clock) *Registry {
+	return &Registry{
+		clock:  clock,
 		config: &Config{},
+		writer: mw,
 	}
 }