Consolidate configunmarshaler into generic implementation

.chloggen/generic-configunmarshaler.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: configunmarshaler
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Consolidate package into generic implementation
+
+# One or more tracking issues or pull requests related to the change
+issues: [6801]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

otelcol/configprovider.go

@@ -99,10 +99,10 @@ func (cm *configProvider) Get(ctx context.Context, factories Factories) (*Config
 	}
 
 	return &Config{
-		Receivers:  cfg.Receivers.GetReceivers(),
-		Processors: cfg.Processors.GetProcessors(),
-		Exporters:  cfg.Exporters.GetExporters(),
-		Extensions: cfg.Extensions.GetExtensions(),
+		Receivers:  cfg.Receivers.Configs(),
+		Processors: cfg.Processors.Configs(),
+		Exporters:  cfg.Exporters.Configs(),
+		Extensions: cfg.Extensions.Configs(),
 		Service:    cfg.Service,
 	}, nil
 }

otelcol/internal/configunmarshaler/configs.go

@@ -0,0 +1,76 @@
+// 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 configunmarshaler // import "go.opentelemetry.io/collector/otelcol/internal/configunmarshaler"
+
+import (
+	"fmt"
+	"reflect"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/confmap"
+)
+
+type Configs[F component.Factory] struct {
+	cfgs map[component.ID]component.Config
+
+	factories map[component.Type]F
+}
+
+func NewConfigs[F component.Factory](factories map[component.Type]F) *Configs[F] {
+	return &Configs[F]{factories: factories}
+}
+
+func (c *Configs[F]) Unmarshal(conf *confmap.Conf) error {
+	rawCfgs := make(map[component.ID]map[string]interface{})
+	if err := conf.Unmarshal(&rawCfgs, confmap.WithErrorUnused()); err != nil {
+		return err
+	}
+
+	// Prepare resulting map.
+	c.cfgs = make(map[component.ID]component.Config)
+	// Iterate over raw configs and create a config for each.
+	for id, value := range rawCfgs {
+		// Find factory based on component kind and type that we read from config source.
+		factory, ok := c.factories[id.Type()]
+		if !ok {
+			return errorUnknownType(id, reflect.ValueOf(c.factories).MapKeys())
+		}
+
+		// Create the default config for this component.
+		cfg := factory.CreateDefaultConfig()
+
+		// Now that the default config struct is created we can Unmarshal into it,
+		// and it will apply user-defined config on top of the default.
+		if err := component.UnmarshalConfig(confmap.NewFromStringMap(value), cfg); err != nil {
+			return errorUnmarshalError(id, err)
+		}
+
+		c.cfgs[id] = cfg
+	}
+
+	return nil
+}
+
+func (c *Configs[F]) Configs() map[component.ID]component.Config {
+	return c.cfgs
+}
+
+func errorUnknownType(id component.ID, factories []reflect.Value) error {
+	return fmt.Errorf("unknown type: %q for id: %q (valid values: %v)", id.Type(), id, factories)
+}
+
+func errorUnmarshalError(id component.ID, err error) error {
+	return fmt.Errorf("error reading configuration for %q: %w", id, err)
+}

otelcol/internal/configunmarshaler/configs_test.go

@@ -0,0 +1,147 @@
+// 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 configunmarshaler
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/confmap"
+	"go.opentelemetry.io/collector/exporter/exportertest"
+	"go.opentelemetry.io/collector/extension/extensiontest"
+	"go.opentelemetry.io/collector/processor/processortest"
+	"go.opentelemetry.io/collector/receiver/receivertest"
+)
+
+var testKinds = []struct {
+	kind      string
+	factories map[component.Type]component.Factory
+}{
+	{
+		kind: "receiver",
+		factories: map[component.Type]component.Factory{
+			"nop": receivertest.NewNopFactory(),
+		},
+	},
+	{
+		kind: "processor",
+		factories: map[component.Type]component.Factory{
+			"nop": processortest.NewNopFactory(),
+		},
+	},
+	{
+		kind: "exporter",
+		factories: map[component.Type]component.Factory{
+			"nop": exportertest.NewNopFactory(),
+		},
+	},
+	{
+		kind: "extension",
+		factories: map[component.Type]component.Factory{
+			"nop": extensiontest.NewNopFactory(),
+		},
+	},
+}
+
+func TestUnmarshal(t *testing.T) {
+	for _, tk := range testKinds {
+		t.Run(tk.kind, func(t *testing.T) {
+			cfgs := NewConfigs(tk.factories)
+			conf := confmap.NewFromStringMap(map[string]interface{}{
+				"nop":              nil,
+				"nop/my" + tk.kind: nil,
+			})
+			require.NoError(t, cfgs.Unmarshal(conf))
+
+			assert.Equal(t, map[component.ID]component.Config{
+				component.NewID("nop"):                       tk.factories["nop"].CreateDefaultConfig(),
+				component.NewIDWithName("nop", "my"+tk.kind): tk.factories["nop"].CreateDefaultConfig(),
+			}, cfgs.Configs())
+		})
+	}
+}
+
+func TestUnmarshalError(t *testing.T) {
+	for _, tk := range testKinds {
+		t.Run(tk.kind, func(t *testing.T) {
+			var testCases = []struct {
+				name string
+				conf *confmap.Conf
+				// string that the error must contain
+				expectedError string
+			}{
+				{
+					name: "invalid-type",
+					conf: confmap.NewFromStringMap(map[string]interface{}{
+						"nop":     nil,
+						"/custom": nil,
+					}),
+					expectedError: "the part before / should not be empty",
+				},
+				{
+					name: "invalid-name-after-slash",
+					conf: confmap.NewFromStringMap(map[string]interface{}{
+						"nop":  nil,
+						"nop/": nil,
+					}),
+					expectedError: "the part after / should not be empty",
+				},
+				{
+					name: "unknown-type",
+					conf: confmap.NewFromStringMap(map[string]interface{}{
+						"nosuch" + tk.kind: nil,
+					}),
+					expectedError: "unknown type: \"nosuch" + tk.kind + "\"",
+				},
+				{
+					name: "duplicate",
+					conf: confmap.NewFromStringMap(map[string]interface{}{
+						"nop /my" + tk.kind + " ": nil,
+						" nop/ my" + tk.kind:      nil,
+					}),
+					expectedError: "duplicate name",
+				},
+				{
+					name: "invalid-section",
+					conf: confmap.NewFromStringMap(map[string]interface{}{
+						"nop": map[string]interface{}{
+							"unknown_section": tk.kind,
+						},
+					}),
+					expectedError: "error reading configuration for \"nop\"",
+				},
+				{
+					name: "invalid-sub-config",
+					conf: confmap.NewFromStringMap(map[string]interface{}{
+						"nop": "tests",
+					}),
+					expectedError: "'[nop]' expected a map, got 'string'",
+				},
+			}
+
+			for _, tt := range testCases {
+				t.Run(tt.name, func(t *testing.T) {
+					cfgs := NewConfigs(tk.factories)
+					err := cfgs.Unmarshal(tt.conf)
+					require.Error(t, err)
+					assert.Contains(t, err.Error(), tt.expectedError)
+				})
+			}
+		})
+	}
+}