[open-telemetryGH-6629] config: Handle null attributes as invalid

Author: mikeblum

config/testdata/invalid_empty.yaml

@@ -0,0 +1,9 @@
+# The file format version.
+file_format: "0.3"
+
+# Configure if the SDK is disabled or not. This is not required to be provided to ensure the SDK isn't disabled, the default value when this is not provided is for the SDK to be enabled.
+# disabled: false
+
+resource:
+ attributes:
+  -

config/v0.3.0/config.go

@@ -143,11 +143,12 @@ func WithOpenTelemetryConfiguration(cfg OpenTelemetryConfiguration) Configuratio
 // ParseYAML parses a YAML configuration file into an OpenTelemetryConfiguration.
 func ParseYAML(file []byte) (*OpenTelemetryConfiguration, error) {
 	var cfg OpenTelemetryConfiguration
-	err := yaml.Unmarshal(file, &cfg)
-	if err != nil {
+	if err := yaml.Unmarshal(file, &cfg); err != nil {
+		return nil, err
+	}
+	if err, ok := validateConfig(&cfg); err != nil || !ok {
 		return nil, err
 	}
-
 	return &cfg, nil
 }
 

config/v0.3.0/config_test.go

@@ -399,6 +399,12 @@ func TestParseYAML(t *testing.T) {
 				FileFormat: ptr("0.1"),
 			},
 		},
+		{
+			name:  "invalid empty config",
+			input: "invalid_empty.yaml",
+			wantErr: errors.New(`yaml: unmarshal errors:
+			line 3: cannot unmarshal null values`),
+		},
 		{
 			name:  "invalid config",
 			input: "invalid_bool.yaml",

config/v0.3.0/validate_config.go

@@ -0,0 +1,28 @@
+package config // import "go.opentelemetry.io/contrib/config/v0.3.0"
+
+import (
+	"errors"
+	"fmt"
+)
+
+const (
+	errCtx string = "invalid OpenTelemetryConfiguration:"
+)
+
+func validateConfig(config *OpenTelemetryConfiguration) (error, bool) {
+	if config == nil {
+		return errors.New("invalid OpenTelemetryConfiguration: nil config"), false
+	}
+	// error on non-empty null values
+	if config.Resource != nil {
+		for n, attr := range config.Resource.Attributes {
+			if attr == (AttributeNameValue{}) {
+				return fmt.Errorf("%s empty Resource.Attribute[%d]", errCtx, n), false
+			}
+			if attr.Value == nil {
+				return fmt.Errorf("%s missing Resource.Attribute[%d] value", errCtx, n), false
+			}
+		}
+	}
+	return nil, true
+}

config/v0.3.0/validate_config_test.go

@@ -0,0 +1,56 @@
+package config
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestConfig(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   *OpenTelemetryConfiguration
+		wantErr error
+		wantOK  bool
+	}{
+		{
+			name: "empty resource attribute",
+			input: &OpenTelemetryConfiguration{
+				Resource: &Resource{
+					Attributes: []AttributeNameValue{
+						{},
+					},
+				},
+			},
+			wantErr: errors.New(errCtx + " empty Resource.Attribute[0]"),
+		},
+		{
+			name: "missing resource attribute value",
+			input: &OpenTelemetryConfiguration{
+				Resource: &Resource{
+					Attributes: []AttributeNameValue{
+						{
+							Name:  "empty value",
+							Value: nil,
+						},
+					},
+				},
+			},
+			wantErr: errors.New(errCtx + " missing Resource.Attribute[0] value"),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err, ok := validateConfig(tt.input)
+			if tt.wantErr != nil {
+				require.Error(t, err)
+				require.Equal(t, tt.wantErr.Error(), err.Error())
+			} else {
+				require.NoError(t, err)
+			}
+			assert.Equal(t, tt.wantOK, ok)
+		})
+	}
+}