[extension/clientaddrmiddleware] Add initial clientaddrmiddleware extension (#930)

* [extension/clientaddrmiddleware] Add initial `clientaddrmiddleware` extension

* Run `make goporto`

* Run ` make gogenerate && make license-update && make lint`

* Change configuration to `metadata_keys`

* Update README.md to describe middleware that uses a predefined list of keys

Author: isaacaflores2

extension/clientaddrmiddlewareextension/Makefile

@@ -0,0 +1 @@
+include ../../Makefile.Common

extension/clientaddrmiddlewareextension/README.md

@@ -0,0 +1,33 @@
+# Client Address Middleware Extension
+
+> [!WARNING]
+> 🚧 This component is a work in progress
+
+The client address middleware provides the ability to set the [`client.Info.Addr`](https://github.com/open-telemetry/opentelemetry-collector/blob/client/v1.47.0/client/client.go#L95) based on the following metadata keys:
+- `forwarded`
+- `x-real-ip`
+- `x-forwarded-for`
+
+Keys are processed in the above order, the first valid value is used to set the client address. If there are no valid addresses found, the client address is not updated.
+
+## Configuration
+Receivers should be configured with `include_metadata: true`, so that the context includes client metadata keys.
+
+### Example
+The following example configures both the otlp `grpc` and `http` receivers with the client address middleware.
+```yaml
+extensions:
+  clientaddrmiddleware: {}
+    
+receivers:
+  otlp:
+    protocols:
+      http:
+        include_metadata: true
+        middlewares:
+          - id: clientaddrmiddleware
+      grpc:
+        include_metadata: true
+        middlewares:
+        - id: clientaddrmiddleware
+```

extension/clientaddrmiddlewareextension/config.go

@@ -0,0 +1,29 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you 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 clientaddrmiddlewareextension // import "github.com/elastic/opentelemetry-collector-components/extension/clientaddrmiddlewareextension"
+
+import (
+	"go.opentelemetry.io/collector/component"
+)
+
+type Config struct {
+}
+
+func createDefaultConfig() component.Config {
+	return &Config{}
+}

extension/clientaddrmiddlewareextension/doc.go

@@ -0,0 +1,20 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you 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.
+
+//go:generate mdatagen metadata.yaml
+
+package clientaddrmiddlewareextension // import "github.com/elastic/opentelemetry-collector-components/extension/clientaddrmiddlewareextension"

extension/clientaddrmiddlewareextension/factory.go

@@ -0,0 +1,40 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you 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 clientaddrmiddlewareextension // import "github.com/elastic/opentelemetry-collector-components/extension/clientaddrmiddlewareextension"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/extension"
+
+	"github.com/elastic/opentelemetry-collector-components/extension/clientaddrmiddlewareextension/internal/metadata"
+)
+
+func NewFactory() extension.Factory {
+	return extension.NewFactory(
+		metadata.Type,
+		createDefaultConfig,
+		createExtension,
+		metadata.ExtensionStability,
+	)
+}
+
+func createExtension(_ context.Context, set extension.Settings, cfg component.Config) (extension.Extension, error) {
+	return newClientAddrMiddleware(cfg.(*Config), set)
+}

extension/clientaddrmiddlewareextension/generated_component_test.go

@@ -0,0 +1,50 @@
+module github.com/elastic/opentelemetry-collector-components/extension/clientaddrmiddlewareextension
+
+go 1.24.0
+
+require (
+	github.com/stretchr/testify v1.11.1
+	go.opentelemetry.io/collector/component v1.47.0
+	go.opentelemetry.io/collector/component/componenttest v0.141.0
+	go.opentelemetry.io/collector/confmap v1.47.0
+	go.opentelemetry.io/collector/extension v1.47.0
+	go.opentelemetry.io/collector/extension/extensiontest v0.141.0
+	go.uber.org/goleak v1.3.0
+	google.golang.org/grpc v1.77.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
+	github.com/gobwas/glob v0.2.3 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/hashicorp/go-version v1.7.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/knadh/koanf/maps v0.1.2 // indirect
+	github.com/knadh/koanf/providers/confmap v1.0.0 // indirect
+	github.com/knadh/koanf/v2 v2.3.0 // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
+	go.opentelemetry.io/collector/featuregate v1.47.0 // indirect
+	go.opentelemetry.io/collector/pdata v1.47.0 // indirect
+	go.opentelemetry.io/otel v1.38.0 // indirect
+	go.opentelemetry.io/otel/metric v1.38.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.38.0 // indirect
+	go.opentelemetry.io/otel/sdk/metric v1.38.0 // indirect
+	go.opentelemetry.io/otel/trace v1.38.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	go.uber.org/zap v1.27.1 // indirect
+	go.yaml.in/yaml/v3 v3.0.4 // indirect
+	golang.org/x/net v0.46.1-0.20251013234738-63d1a5100f82 // indirect
+	golang.org/x/sys v0.37.0 // indirect
+	golang.org/x/text v0.30.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251022142026-3a174f9686a8 // indirect
+	google.golang.org/protobuf v1.36.10 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)