Add component config validation (#30)

Prior to this commit, the config validation wasn't being performed by the playground, and invalid configurations were run as it's. This PR changed the config parsing logic to also call the `xconfmap.Validator.Validate` function, making it closer to a real collector and avoiding running config with invalid config values.

Author: edmocosta

Makefile

@@ -72,4 +72,4 @@ fmt:
 .PHONY: tidy
 tidy:
 	rm -fr go.sum
-	$(GOCMD) mod tidy -compat=1.22.0
+	$(GOCMD) mod tidy -compat=1.24.0

go.mod

@@ -10,6 +10,7 @@ require (
 	go.opentelemetry.io/collector/component v1.49.0
 	go.opentelemetry.io/collector/component/componenttest v0.143.0
 	go.opentelemetry.io/collector/confmap v1.49.0
+	go.opentelemetry.io/collector/confmap/xconfmap v0.143.0
 	go.opentelemetry.io/collector/consumer v1.49.0
 	go.opentelemetry.io/collector/consumer/xconsumer v0.143.0
 	go.opentelemetry.io/collector/pdata v1.49.0

internal/config.go

@@ -26,6 +26,7 @@ import (
 	"github.com/go-viper/mapstructure/v2"
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/confmap"
+	"go.opentelemetry.io/collector/confmap/xconfmap"
 	"gopkg.in/yaml.v3"
 )
 
@@ -63,13 +64,8 @@ func parseConfig[C any](id component.ID, yamlConfig string, createDefaultConfig
 		return parseMultipleConfigs[C](yamlConfig, deserializedConf, createDefaultConfig)
 	}
 
-	configMap := make(map[string]any)
-	for k, v := range deserializedConf.ToStringMap() {
-		configMap[k] = escapeDollarSigns(v)
-	}
-
 	defaultConfig := createDefaultConfig()
-	err = confmap.NewFromStringMap(configMap).Unmarshal(&defaultConfig)
+	err = unmarshalValidConfig(deserializedConf, defaultConfig)
 	if err != nil {
 		return nil, err
 	}
@@ -89,13 +85,8 @@ func parseMultipleConfigs[C any](yamlConfig string, deserializedConf *confmap.Co
 			return nil, err
 		}
 
-		subConfigMap := map[string]any{}
-		for k, v := range sub.ToStringMap() {
-			subConfigMap[k] = escapeDollarSigns(v)
-		}
-
 		defaultConfig := createDefaultConfig()
-		err = confmap.NewFromStringMap(subConfigMap).Unmarshal(&defaultConfig)
+		err = unmarshalValidConfig(sub, defaultConfig)
 		if err != nil {
 			return nil, err
 		}
@@ -106,6 +97,25 @@ func parseMultipleConfigs[C any](yamlConfig string, deserializedConf *confmap.Co
 	return configs, nil
 }
 
+func unmarshalValidConfig[C any](cfg *confmap.Conf, defaultConfig C) error {
+	subConfigMap := map[string]any{}
+	for k, v := range cfg.ToStringMap() {
+		subConfigMap[k] = escapeDollarSigns(v)
+	}
+
+	err := confmap.NewFromStringMap(subConfigMap).Unmarshal(&defaultConfig)
+	if err != nil {
+		return err
+	}
+
+	validator, ok := any(defaultConfig).(xconfmap.Validator)
+	if ok {
+		return validator.Validate()
+	}
+
+	return nil
+}
+
 func sortedConfigKeys(yamlData string) ([]string, error) {
 	var root yaml.Node
 	if err := yaml.Unmarshal([]byte(yamlData), &root); err != nil {

internal/config_test.go

@@ -20,6 +20,7 @@
 package internal
 
 import (
+	"errors"
 	"testing"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/processor/transformprocessor"
@@ -52,6 +53,54 @@ func Test_parseConfig_singleConfig(t *testing.T) {
 	require.NotEmpty(t, pc.MetricStatements)
 }
 
+func Test_parseConfig_configValidator(t *testing.T) {
+	id := component.MustNewID("test")
+	tests := []struct {
+		name      string
+		config    string
+		expectErr bool
+	}{
+		{
+			name:      "valid single config",
+			config:    "valid: true",
+			expectErr: false,
+		},
+		{
+			name:      "invalid single config",
+			config:    "valid: false",
+			expectErr: true,
+		},
+		{
+			name:      "valid multiple config",
+			config:    "test:\n valid: true\ntest/b:\n valid: true",
+			expectErr: false,
+		},
+		{
+			name:      "invalid multiple config",
+			config:    "test:\n valid: true\ntest/b:\n valid: false",
+			expectErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := parseConfig[mockConfig](
+				id,
+				tt.config,
+				func() *mockConfig {
+					return &mockConfig{Valid: !tt.expectErr}
+				},
+			)
+
+			if tt.expectErr {
+				require.ErrorIs(t, err, errInvalidMockConfig)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
+
 func Test_parseConfig_multipleConfig(t *testing.T) {
 	config := readTestData(t, configMultiple)
 	allConfigs, err := parseConfig[transformprocessor.Config](
@@ -87,3 +136,18 @@ func Test_parseConfig_invalidConfig(t *testing.T) {
 	)
 	require.ErrorContains(t, err, "cannot be used as a Conf")
 }
+
+var (
+	errInvalidMockConfig = errors.New("config validation failed")
+)
+
+type mockConfig struct {
+	Valid bool `mapstructure:"valid"`
+}
+
+func (m *mockConfig) Validate() error {
+	if m.Valid {
+		return nil
+	}
+	return errInvalidMockConfig
+}