support ClientEncryption as already provided by MongoDB (#14)

Fixes #13

wrapped_client_ecryption.go

@@ -0,0 +1,80 @@
+// Copyright 2018, OpenCensus 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 mongowrapper
+
+import (
+	"context"
+
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+)
+
+type WrappedClientEncryption struct {
+	cc *mongo.ClientEncryption
+}
+
+func (wc *WrappedClient) NewClientEncryption(opts ...*options.ClientEncryptionOptions) (*WrappedClientEncryption, error) {
+	client, err := mongo.NewClientEncryption(wc.Client(), opts...)
+	if err != nil {
+		return nil, err
+	}
+	return &WrappedClientEncryption{cc: client}, nil
+}
+
+func (wce *WrappedClientEncryption) CreateDataKey(ctx context.Context, kmsProvider string, opts ...*options.DataKeyOptions) (primitive.Binary, error) {
+	ctx, span := roundtripTrackingSpan(ctx, "go.mongodb.org/mongo-driver.ClientEncryption.CreateDataKey")
+	defer span.end(ctx)
+
+	id, err := wce.cc.CreateDataKey(ctx, kmsProvider, opts...)
+	if err != nil {
+		span.setError(err)
+	}
+	return id, err
+}
+
+func (wce *WrappedClientEncryption) Encrypt(ctx context.Context, val bson.RawValue, opts ...*options.EncryptOptions) (primitive.Binary, error) {
+	ctx, span := roundtripTrackingSpan(ctx, "go.mongodb.org/mongo-driver.ClientEncryption.Encrypt")
+	defer span.end(ctx)
+
+	value, err := wce.cc.Encrypt(ctx, val, opts...)
+	if err != nil {
+		span.setError(err)
+	}
+	return value, err
+}
+
+func (wce *WrappedClientEncryption) Decrypt(ctx context.Context, val primitive.Binary) (bson.RawValue, error) {
+	ctx, span := roundtripTrackingSpan(ctx, "go.mongodb.org/mongo-driver.ClientEncryption.Decrypt")
+	defer span.end(ctx)
+
+	value, err := wce.cc.Decrypt(ctx, val)
+	if err != nil {
+		span.setError(err)
+	}
+	return value, err
+}
+
+func (wce *WrappedClientEncryption) Close(ctx context.Context) error {
+	ctx, span := roundtripTrackingSpan(ctx, "go.mongodb.org/mongo-driver.ClientEncryption.Close")
+	defer span.end(ctx)
+
+	err := wce.cc.Close(ctx)
+	if err != nil {
+		span.setError(err)
+	}
+	return err
+}