status: Introduce FromContextError convenience function (grpc#2057)

status/go16.go

@@ -0,0 +1,42 @@
+// +build go1.6,!go1.7
+
+/*
+ *
+ * Copyright 2018 gRPC 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 status
+
+import (
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+)
+
+// FromContextError converts a context error into a Status.  It returns a
+// Status with codes.OK if err is nil, or a Status with codes.Unknown if err is
+// non-nil and not a context error.
+func FromContextError(err error) *Status {
+	switch err {
+	case nil:
+		return New(codes.OK, "")
+	case context.DeadlineExceeded:
+		return New(codes.DeadlineExceeded, err.Error())
+	case context.Canceled:
+		return New(codes.Canceled, err.Error())
+	default:
+		return New(codes.Unknown, err.Error())
+	}
+}

status/go17.go

@@ -0,0 +1,44 @@
+// +build go1.7
+
+/*
+ *
+ * Copyright 2018 gRPC 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 status
+
+import (
+	"context"
+
+	netctx "golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+)
+
+// FromContextError converts a context error into a Status.  It returns a
+// Status with codes.OK if err is nil, or a Status with codes.Unknown if err is
+// non-nil and not a context error.
+func FromContextError(err error) *Status {
+	switch err {
+	case nil:
+		return New(codes.OK, "")
+	case context.DeadlineExceeded, netctx.DeadlineExceeded:
+		return New(codes.DeadlineExceeded, err.Error())
+	case context.Canceled, netctx.Canceled:
+		return New(codes.Canceled, err.Error())
+	default:
+		return New(codes.Unknown, err.Error())
+	}
+}

status/go17_test.go

@@ -0,0 +1,44 @@
+// +build go1.7
+
+/*
+ *
+ * Copyright 2018 gRPC 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 status
+
+import (
+	"context"
+	"testing"
+
+	"google.golang.org/grpc/codes"
+)
+
+func TestFromStdContextError(t *testing.T) {
+	testCases := []struct {
+		in   error
+		want *Status
+	}{
+		{in: context.DeadlineExceeded, want: New(codes.DeadlineExceeded, context.DeadlineExceeded.Error())},
+		{in: context.Canceled, want: New(codes.Canceled, context.Canceled.Error())},
+	}
+	for _, tc := range testCases {
+		got := FromContextError(tc.in)
+		if got.Code() != tc.want.Code() || got.Message() != tc.want.Message() {
+			t.Errorf("FromContextError(%v) = %v; want %v", tc.in, got, tc.want)
+		}
+	}
+}

status/status_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/golang/protobuf/ptypes"
 	apb "github.com/golang/protobuf/ptypes/any"
 	dpb "github.com/golang/protobuf/ptypes/duration"
+	"golang.org/x/net/context"
 	cpb "google.golang.org/genproto/googleapis/rpc/code"
 	epb "google.golang.org/genproto/googleapis/rpc/errdetails"
 	spb "google.golang.org/genproto/googleapis/rpc/status"
@@ -327,3 +328,21 @@ func mustMarshalAny(msg proto.Message) *apb.Any {
 	}
 	return any
 }
+
+func TestFromContextError(t *testing.T) {
+	testCases := []struct {
+		in   error
+		want *Status
+	}{
+		{in: nil, want: New(codes.OK, "")},
+		{in: context.DeadlineExceeded, want: New(codes.DeadlineExceeded, context.DeadlineExceeded.Error())},
+		{in: context.Canceled, want: New(codes.Canceled, context.Canceled.Error())},
+		{in: errors.New("other"), want: New(codes.Unknown, "other")},
+	}
+	for _, tc := range testCases {
+		got := FromContextError(tc.in)
+		if got.Code() != tc.want.Code() || got.Message() != tc.want.Message() {
+			t.Errorf("FromContextError(%v) = %v; want %v", tc.in, got, tc.want)
+		}
+	}
+}