Add api/oterror package

api/metric/sync.go

@@ -16,9 +16,9 @@ package metric
 
 import (
 	"context"
-	"errors"
 
 	"go.opentelemetry.io/otel/api/kv"
+	"go.opentelemetry.io/otel/api/oterror"
 )
 
 // Measurement is used for reporting a synchronous batch of metric
@@ -45,10 +45,6 @@ type asyncInstrument struct {
 	instrument AsyncImpl
 }
 
-// ErrSDKReturnedNilImpl is used when one of the `MeterImpl` New
-// methods returns nil.
-var ErrSDKReturnedNilImpl = errors.New("SDK returned a nil implementation")
-
 // SyncImpl returns the instrument that created this measurement.
 // This returns an implementation-level object for use by the SDK,
 // users should not refer to this.
@@ -114,7 +110,7 @@ func (h syncBoundInstrument) Unbind() {
 func checkNewAsync(instrument AsyncImpl, err error) (asyncInstrument, error) {
 	if instrument == nil {
 		if err == nil {
-			err = ErrSDKReturnedNilImpl
+			err = oterror.SDKReturnedNilImpl
 		}
 		instrument = NoopAsync{}
 	}
@@ -129,7 +125,7 @@ func checkNewAsync(instrument AsyncImpl, err error) (asyncInstrument, error) {
 func checkNewSync(instrument SyncImpl, err error) (syncInstrument, error) {
 	if instrument == nil {
 		if err == nil {
-			err = ErrSDKReturnedNilImpl
+			err = oterror.SDKReturnedNilImpl
 		}
 		// Note: an alternate behavior would be to synthesize a new name
 		// or group all duplicately-named instruments of a certain type

api/oterror/doc.go

@@ -0,0 +1,26 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+* The oterror package provides unified error interactions in OpenTelemetry.
+* This includes providing standardized errors common to OpenTelemetry (APIs,
+* SDKs, and exporters). Additionally it provides an API for unified error
+* handling in OpenTelemetry.
+*
+* The unified error handling interface is used for any error that
+* OpenTelemetry component are not able to remediate on their own, instead
+* handeling them in a uniform and user-defined way.
+ */
+
+package oterror

api/oterror/errors.go

@@ -0,0 +1,22 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package oterror
+
+import "errors"
+
+var (
+	// SDKReturnedNilImpl is returned when a new `MeterImpl` returns nil.
+	SDKReturnedNilImpl = errors.New("SDK returned a nil implementation")
+)

api/oterror/handler.go

@@ -0,0 +1,23 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package oterror
+
+// Handler performs a required function when an irremediable event is
+// encountered.
+type Handler interface {
+	// Error handles any error that irremediable by an OpenTelemetry
+	// component.
+	Error(error)
+}