Remove the oterror package (#1026)

* Break up the oterror package

* Update use of ErrorHandler in project

* Update handler naming and comments

api/global/handler.go

@@ -20,73 +20,72 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"go.opentelemetry.io/otel/api/oterror"
+	"go.opentelemetry.io/otel"
 )
 
 var (
-	// globalHandler provides an oterror.Handler that can be used throughout
-	// an OpenTelemetry instrumented project. When a user specified Handler
-	// is registered (`SetHandler`) all calls to `Handle` will be delegated
-	// to the registered Handler.
-	globalHandler = &handler{
+	// globalErrorHandler provides an ErrorHandler that can be used
+	// throughout an OpenTelemetry instrumented project. When a user
+	// specified ErrorHandler is registered (`SetErrorHandler`) all calls to
+	// `Handle` and will be delegated to the registered ErrorHandler.
+	globalErrorHandler = &loggingErrorHandler{
 		l: log.New(os.Stderr, "", log.LstdFlags),
 	}
 
-	// delegateHanderOnce ensures that a user provided Handler is only ever
-	// registered once.
-	delegateHanderOnce sync.Once
+	// delegateErrorHandlerOnce ensures that a user provided ErrorHandler is
+	// only ever registered once.
+	delegateErrorHandlerOnce sync.Once
 
-	// Ensure the handler implements oterror.Handle at build time.
-	_ oterror.Handler = (*handler)(nil)
+	// Comiple time check that loggingErrorHandler implements ErrorHandler.
+	_ otel.ErrorHandler = (*loggingErrorHandler)(nil)
 )
 
-// handler logs all errors to STDERR.
-type handler struct {
+// loggingErrorHandler logs all errors to STDERR.
+type loggingErrorHandler struct {
 	delegate atomic.Value
 
 	l *log.Logger
 }
 
-// setDelegate sets the handler delegate if one is not already set.
-func (h *handler) setDelegate(d oterror.Handler) {
+// setDelegate sets the ErrorHandler delegate if one is not already set.
+func (h *loggingErrorHandler) setDelegate(d otel.ErrorHandler) {
 	if h.delegate.Load() != nil {
 		// Delegate already registered
 		return
 	}
 	h.delegate.Store(d)
 }
 
-// Handle implements oterror.Handler.
-func (h *handler) Handle(err error) {
+// Handle implements otel.ErrorHandler.
+func (h *loggingErrorHandler) Handle(err error) {
 	if d := h.delegate.Load(); d != nil {
-		d.(oterror.Handler).Handle(err)
+		d.(otel.ErrorHandler).Handle(err)
 		return
 	}
 	h.l.Print(err)
 }
 
-// Handler returns the global Handler instance. If no Handler instance has
-// be explicitly set yet, a default Handler is returned that logs to STDERR
-// until an Handler is set (all functionality is delegated to the set
-// Handler once it is set).
-func Handler() oterror.Handler {
-	return globalHandler
+// ErrorHandler returns the global ErrorHandler instance. If no ErrorHandler
+// instance has been set (`SetErrorHandler`), the default ErrorHandler which
+// logs errors to STDERR is returned.
+func ErrorHandler() otel.ErrorHandler {
+	return globalErrorHandler
 }
 
-// SetHandler sets the global Handler to be h.
-func SetHandler(h oterror.Handler) {
-	delegateHanderOnce.Do(func() {
-		current := Handler()
+// SetErrorHandler sets the global ErrorHandler to be h.
+func SetErrorHandler(h otel.ErrorHandler) {
+	delegateErrorHandlerOnce.Do(func() {
+		current := ErrorHandler()
 		if current == h {
 			return
 		}
-		if internalHandler, ok := current.(*handler); ok {
+		if internalHandler, ok := current.(*loggingErrorHandler); ok {
 			internalHandler.setDelegate(h)
 		}
 	})
 }
 
-// Handle is a convience function for Handler().Handle(err)
+// Handle is a convience function for ErrorHandler().Handle(err)
 func Handle(err error) {
-	globalHandler.Handle(err)
+	ErrorHandler().Handle(err)
 }

api/global/handler_test.go

@@ -44,20 +44,20 @@ func (l *errLogger) Got() []string {
 type HandlerTestSuite struct {
 	suite.Suite
 
-	origHandler *handler
+	origHandler *loggingErrorHandler
 	errLogger   *errLogger
 }
 
 func (s *HandlerTestSuite) SetupSuite() {
 	s.errLogger = new(errLogger)
-	s.origHandler = globalHandler
-	globalHandler = &handler{
+	s.origHandler = globalErrorHandler
+	globalErrorHandler = &loggingErrorHandler{
 		l: log.New(s.errLogger, "", 0),
 	}
 }
 
 func (s *HandlerTestSuite) TearDownSuite() {
-	globalHandler = s.origHandler
+	globalErrorHandler = s.origHandler
 }
 
 func (s *HandlerTestSuite) SetupTest() {
@@ -66,7 +66,7 @@ func (s *HandlerTestSuite) SetupTest() {
 
 func (s *HandlerTestSuite) TestGlobalHandler() {
 	errs := []string{"one", "two"}
-	Handler().Handle(errors.New(errs[0]))
+	ErrorHandler().Handle(errors.New(errs[0]))
 	Handle(errors.New(errs[1]))
 	s.Assert().Equal(errs, s.errLogger.Got())
 }
@@ -122,10 +122,10 @@ func (s *HandlerTestSuite) TestNoDropsOnDelegate() {
 
 	// Change to another Handler. We are testing this is loss-less.
 	newErrLogger := new(errLogger)
-	secondary := &handler{
+	secondary := &loggingErrorHandler{
 		l: log.New(newErrLogger, "", 0),
 	}
-	SetHandler(secondary)
+	SetErrorHandler(secondary)
 	s.Require().NoError(wait(pause), "switched to new Handler")
 
 	// Testing done, stop sending errors.

api/metric/api_test.go

@@ -22,7 +22,6 @@ import (
 
 	"go.opentelemetry.io/otel/api/kv"
 	"go.opentelemetry.io/otel/api/metric"
-	"go.opentelemetry.io/otel/api/oterror"
 	"go.opentelemetry.io/otel/api/unit"
 	mockTest "go.opentelemetry.io/otel/internal/metric"
 
@@ -392,7 +391,7 @@ func TestWrappedInstrumentError(t *testing.T) {
 
 	valuerecorder, err := meter.NewInt64ValueRecorder("test.valuerecorder")
 
-	require.Equal(t, err, oterror.ErrSDKReturnedNilImpl)
+	require.Equal(t, err, metric.ErrSDKReturnedNilImpl)
 	require.NotNil(t, valuerecorder.SyncImpl())
 
 	observer, err := meter.NewInt64ValueObserver("test.observer", func(_ context.Context, result metric.Int64ObserverResult) {})

api/metric/sync.go

@@ -16,11 +16,14 @@ package metric
 
 import (
 	"context"
+	"errors"
 
 	"go.opentelemetry.io/otel/api/kv"
-	"go.opentelemetry.io/otel/api/oterror"
 )
 
+// ErrSDKReturnedNilImpl is returned when a new `MeterImpl` returns nil.
+var ErrSDKReturnedNilImpl = errors.New("SDK returned a nil implementation")
+
 // Measurement is used for reporting a synchronous batch of metric
 // values. Instances of this type should be created by synchronous
 // instruments (e.g., Int64Counter.Measurement()).
@@ -110,7 +113,7 @@ func (h syncBoundInstrument) Unbind() {
 func checkNewAsync(instrument AsyncImpl, err error) (asyncInstrument, error) {
 	if instrument == nil {
 		if err == nil {
-			err = oterror.ErrSDKReturnedNilImpl
+			err = ErrSDKReturnedNilImpl
 		}
 		instrument = NoopAsync{}
 	}
@@ -125,7 +128,7 @@ func checkNewAsync(instrument AsyncImpl, err error) (asyncInstrument, error) {
 func checkNewSync(instrument SyncImpl, err error) (syncInstrument, error) {
 	if instrument == nil {
 		if err == nil {
-			err = oterror.ErrSDKReturnedNilImpl
+			err = ErrSDKReturnedNilImpl
 		}
 		// Note: an alternate behavior would be to synthesize a new name
 		// or group all duplicately-named instruments of a certain type

api/oterror/handler.go → error_handler.go

@@ -12,10 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package oterror
+package otel
 
-// Handler handles irremediable events.
-type Handler interface {
+// ErrorHandler handles irremediable events.
+type ErrorHandler interface {
 	// Handle handles any error deemed irremediable by an OpenTelemetry
 	// component.
 	Handle(error)

sdk/metric/controller/push/push_test.go

@@ -63,7 +63,7 @@ var testHandler *handler
 
 func init() {
 	testHandler = new(handler)
-	global.SetHandler(testHandler)
+	global.SetErrorHandler(testHandler)
 }
 
 type testExporter struct {

sdk/metric/correct_test.go

@@ -67,7 +67,7 @@ var testHandler *handler
 
 func init() {
 	testHandler = new(handler)
-	global.SetHandler(testHandler)
+	global.SetErrorHandler(testHandler)
 }
 
 type correctnessProcessor struct {

sdk/trace/trace_test.go

@@ -52,7 +52,7 @@ func init() {
 	tid, _ = apitrace.IDFromHex("01020304050607080102040810203040")
 	sid, _ = apitrace.SpanIDFromHex("0102040810203040")
 
-	global.SetHandler(new(discardHandler))
+	global.SetErrorHandler(new(discardHandler))
 }
 
 func TestTracerFollowsExpectedAPIBehaviour(t *testing.T) {