Add a new bytes provier, allows providing yaml bytes

Open Question: Should the schema be "yaml:" or "bytes:"?

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

config/configmapprovider/bytes.go

@@ -0,0 +1,58 @@
+// 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 configmapprovider // import "go.opentelemetry.io/collector/config/configmapprovider"
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"gopkg.in/yaml.v2"
+
+	"go.opentelemetry.io/collector/config"
+)
+
+const bytesSchemeName = "bytes"
+
+type bytesMapProvider struct{}
+
+// NewBytes returns a new Provider that allows to provide yaml bytes.
+//
+// This Provider supports "bytes" scheme, and can be called with a "location" that follows:
+//   bytes-location   = "bytes:" yaml-bytes
+//
+// Examples:
+// `bytes:processors::batch::timeout: 2s`
+// `bytes:processors::batch/foo::timeout: 3s`
+func NewBytes() Provider {
+	return &bytesMapProvider{}
+}
+
+func (s *bytesMapProvider) Retrieve(_ context.Context, location string, _ WatcherFunc) (Retrieved, error) {
+	if !strings.HasPrefix(location, bytesSchemeName+":") {
+		return Retrieved{}, fmt.Errorf("%v location is not supported by %v provider", location, bytesSchemeName)
+	}
+
+	var data map[string]interface{}
+	if err := yaml.Unmarshal([]byte(location[len(bytesSchemeName)+1:]), &data); err != nil {
+		return Retrieved{}, fmt.Errorf("unable to parse yaml: %w", err)
+	}
+
+	return Retrieved{Map: config.NewMapFromStringMap(data)}, nil
+}
+
+func (s *bytesMapProvider) Shutdown(context.Context) error {
+	return nil
+}

config/configmapprovider/bytes_test.go

@@ -0,0 +1,75 @@
+// 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 configmapprovider
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBytesProvider_Empty(t *testing.T) {
+	sp := NewBytes()
+	_, err := sp.Retrieve(context.Background(), "", nil)
+	assert.Error(t, err)
+}
+
+func TestBytesProvider_InvalidValue(t *testing.T) {
+	sp := NewBytes()
+	_, err := sp.Retrieve(context.Background(), "bytes::2s", nil)
+	assert.Error(t, err)
+}
+
+func TestBytesProvider(t *testing.T) {
+	sp := NewBytes()
+
+	ret, err := sp.Retrieve(context.Background(), "bytes:processors::batch::timeout: 2s", nil)
+	assert.NoError(t, err)
+	assert.Equal(t, map[string]interface{}{
+		"processors": map[string]interface{}{
+			"batch": map[string]interface{}{
+				"timeout": "2s",
+			},
+		},
+	}, ret.Map.ToStringMap())
+
+	ret, err = sp.Retrieve(context.Background(), "bytes:processors::batch/foo::timeout: 3s", nil)
+	assert.NoError(t, err)
+	assert.Equal(t, map[string]interface{}{
+		"processors": map[string]interface{}{
+			"batch/foo": map[string]interface{}{
+				"timeout": "3s",
+			},
+		},
+	}, ret.Map.ToStringMap())
+
+	ret, err = sp.Retrieve(context.Background(), "bytes:processors: {batch/foo::timeout: 3s, batch::timeout: 2s}", nil)
+	assert.NoError(t, err)
+	assert.Equal(t, map[string]interface{}{
+		"processors": map[string]interface{}{
+			"batch/foo": map[string]interface{}{
+				"timeout": "3s",
+			},
+			"batch": map[string]interface{}{
+				"timeout": "2s",
+			},
+		},
+	}, ret.Map.ToStringMap())
+
+	ret, err = sp.Retrieve(context.Background(), "bytes:processors.batch.timeout: 4s", nil)
+	assert.NoError(t, err)
+	assert.Equal(t, map[string]interface{}{"processors.batch.timeout": "4s"}, ret.Map.ToStringMap())
+}