Middleware: HTTP support (part 3/4)

.chloggen/middleware-http.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# 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: confighttp
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add HTTP middleware support.
+
+# One or more tracking issues or pull requests related to the change
+issues: [12603, 9591, 7441]
+
+# (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:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

cmd/builder/internal/builder/main_test.go

@@ -47,6 +47,7 @@ var replaceModules = []string{
 	"/config/configcompression",
 	"/config/configgrpc",
 	"/config/confighttp",
+	"/config/configmiddleware",
 	"/config/confignet",
 	"/config/configopaque",
 	"/config/configretry",
@@ -79,6 +80,8 @@ var replaceModules = []string{
 	"/extension/extensionauth",
 	"/extension/extensionauth/extensionauthtest",
 	"/extension/extensioncapabilities",
+	"/extension/extensionmiddleware",
+	"/extension/extensionmiddleware/extensionmiddlewaretest",
 	"/extension/extensiontest",
 	"/extension/zpagesextension",
 	"/extension/xextension",

cmd/otelcorecol/builder-config.yaml

@@ -46,6 +46,7 @@ replaces:
   - go.opentelemetry.io/collector/config/configcompression => ../../config/configcompression
   - go.opentelemetry.io/collector/config/configgrpc => ../../config/configgrpc
   - go.opentelemetry.io/collector/config/confighttp => ../../config/confighttp
+  - go.opentelemetry.io/collector/config/configmiddleware => ../../config/configmiddleware
   - go.opentelemetry.io/collector/config/confignet => ../../config/confignet
   - go.opentelemetry.io/collector/config/configopaque => ../../config/configopaque
   - go.opentelemetry.io/collector/config/configretry => ../../config/configretry
@@ -79,6 +80,8 @@ replaces:
   - go.opentelemetry.io/collector/extension/extensionauth => ../../extension/extensionauth
   - go.opentelemetry.io/collector/extension/extensionauth/extensionauthtest => ../../extension/extensionauth/extensionauthtest
   - go.opentelemetry.io/collector/extension/extensioncapabilities => ../../extension/extensioncapabilities
+  - go.opentelemetry.io/collector/extension/extensionmiddleware => ../../extension/extensionmiddleware
+  - go.opentelemetry.io/collector/extension/extensionmiddleware/extensionmiddlewaretest => ../../extension/extensionmiddleware/extensionmiddlewaretest
   - go.opentelemetry.io/collector/extension/extensiontest => ../../extension/extensiontest
   - go.opentelemetry.io/collector/extension/memorylimiterextension => ../../extension/memorylimiterextension
   - go.opentelemetry.io/collector/extension/xextension => ../../extension/xextension

cmd/otelcorecol/go.mod

@@ -89,6 +89,7 @@ require (
 	go.opentelemetry.io/collector/config/configcompression v1.30.0 // indirect
 	go.opentelemetry.io/collector/config/configgrpc v0.124.0 // indirect
 	go.opentelemetry.io/collector/config/confighttp v0.124.0 // indirect
+	go.opentelemetry.io/collector/config/configmiddleware v0.0.0-00010101000000-000000000000 // indirect
 	go.opentelemetry.io/collector/config/confignet v1.30.0 // indirect
 	go.opentelemetry.io/collector/config/configopaque v1.30.0 // indirect
 	go.opentelemetry.io/collector/config/configretry v1.30.0 // indirect
@@ -107,6 +108,7 @@ require (
 	go.opentelemetry.io/collector/exporter/xexporter v0.124.0 // indirect
 	go.opentelemetry.io/collector/extension/extensionauth v1.30.0 // indirect
 	go.opentelemetry.io/collector/extension/extensioncapabilities v0.124.0 // indirect
+	go.opentelemetry.io/collector/extension/extensionmiddleware v1.30.0 // indirect
 	go.opentelemetry.io/collector/extension/extensiontest v0.124.0 // indirect
 	go.opentelemetry.io/collector/extension/xextension v0.124.0 // indirect
 	go.opentelemetry.io/collector/featuregate v1.30.0 // indirect
@@ -186,6 +188,8 @@ replace go.opentelemetry.io/collector/config/configgrpc => ../../config/configgr
 
 replace go.opentelemetry.io/collector/config/confighttp => ../../config/confighttp
 
+replace go.opentelemetry.io/collector/config/configmiddleware => ../../config/configmiddleware
+
 replace go.opentelemetry.io/collector/config/confignet => ../../config/confignet
 
 replace go.opentelemetry.io/collector/config/configopaque => ../../config/configopaque
@@ -252,6 +256,10 @@ replace go.opentelemetry.io/collector/extension/extensionauth/extensionauthtest
 
 replace go.opentelemetry.io/collector/extension/extensioncapabilities => ../../extension/extensioncapabilities
 
+replace go.opentelemetry.io/collector/extension/extensionmiddleware => ../../extension/extensionmiddleware
+
+replace go.opentelemetry.io/collector/extension/extensionmiddleware/extensionmiddlewaretest => ../../extension/extensionmiddleware/extensionmiddlewaretest
+
 replace go.opentelemetry.io/collector/extension/extensiontest => ../../extension/extensiontest
 
 replace go.opentelemetry.io/collector/extension/memorylimiterextension => ../../extension/memorylimiterextension

config/confighttp/README.md

@@ -58,6 +58,7 @@ README](../configtls/README.md).
 - [`http2_ping_timeout`](https://pkg.go.dev/golang.org/x/net/http2#Transport)
 - [`cookies`](https://pkg.go.dev/net/http#CookieJar)
   - [`enabled`] if enabled, the client will store cookies from server responses and reuse them in subsequent requests.
+- [`middlewares`](../configmiddleware/README.md)
 
 Example:
 
@@ -107,6 +108,7 @@ will not be enabled.
 - [`tls`](../configtls/README.md)
 - [`auth`](../configauth/README.md)
   - `request_params`: a list of query parameter names to add to the auth context, along with the HTTP headers
+- [`middlewares`](../configmiddleware/README.md)
 
 You can enable [`attribute processor`][attribute-processor] to append any http header to span's attribute using custom key. You also need to enable the "include_metadata"
 

config/confighttp/client_middleware_test.go

@@ -0,0 +1,255 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package confighttp
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/config/configmiddleware"
+	"go.opentelemetry.io/collector/extension"
+	"go.opentelemetry.io/collector/extension/extensionmiddleware"
+	"go.opentelemetry.io/collector/extension/extensionmiddleware/extensionmiddlewaretest"
+)
+
+// testClientMiddleware is a test middleware that appends a string to the response body
+type testClientMiddleware struct {
+	extension.Extension
+	extensionmiddleware.GetHTTPRoundTripperFunc
+}
+
+func newTestClientMiddleware(name string) component.Component {
+	return &testClientMiddleware{
+		Extension: extensionmiddlewaretest.NewNop(),
+		GetHTTPRoundTripperFunc: func(transport http.RoundTripper) (http.RoundTripper, error) {
+			return extensionmiddlewaretest.HTTPClientFunc(
+				func(req *http.Request) (*http.Response, error) {
+					resp, err := transport.RoundTrip(req)
+					if err != nil {
+						return resp, err
+					}
+
+					// Read the original body
+					body, err := io.ReadAll(resp.Body)
+					if err != nil {
+						return resp, err
+					}
+					_ = resp.Body.Close()
+
+					// Create a new body with the appended text
+					newBody := string(body) + "\r\noutput by " + name
+
+					// Replace the response body
+					resp.Body = io.NopCloser(strings.NewReader(newBody))
+					resp.ContentLength = int64(len(newBody))
+
+					return resp, nil
+				}), nil
+		},
+	}
+}
+
+func newTestClientConfig(name string) configmiddleware.Config {
+	return configmiddleware.Config{
+		ID: component.MustNewID(name),
+	}
+}
+
+func TestClientMiddlewares(t *testing.T) {
+	// Create a test server that returns "OK"
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("OK"))
+	}))
+	defer server.Close()
+
+	// Register two test extensions
+	host := &mockHost{
+		ext: map[component.ID]component.Component{
+			component.MustNewID("test1"): newTestClientMiddleware("test1"),
+			component.MustNewID("test2"): newTestClientMiddleware("test2"),
+		},
+	}
+
+	// Test with different middleware configurations
+	testCases := []struct {
+		name           string
+		middlewares    []configmiddleware.Config
+		expectedOutput string
+	}{
+		{
+			name:           "no_middlewares",
+			middlewares:    nil,
+			expectedOutput: "OK",
+		},
+		{
+			name: "single_middleware",
+			middlewares: []configmiddleware.Config{
+				newTestClientConfig("test1"),
+			},
+			expectedOutput: "OK\r\noutput by test1",
+		},
+		{
+			name: "multiple_middlewares",
+			middlewares: []configmiddleware.Config{
+				newTestClientConfig("test1"),
+				newTestClientConfig("test2"),
+			},
+			expectedOutput: "OK\r\noutput by test2\r\noutput by test1",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Create HTTP client config with the test middlewares
+			clientConfig := ClientConfig{
+				Endpoint:    server.URL,
+				Middlewares: tc.middlewares,
+			}
+
+			// Create the client
+			client, err := clientConfig.ToClient(context.Background(), host, componenttest.NewNopTelemetrySettings())
+			require.NoError(t, err)
+
+			// Create a request to the test server
+			req, err := http.NewRequest(http.MethodGet, server.URL, nil)
+			require.NoError(t, err)
+
+			// Send the request
+			resp, err := client.Do(req)
+			require.NoError(t, err)
+			defer resp.Body.Close()
+
+			// Check the response
+			body, err := io.ReadAll(resp.Body)
+			require.NoError(t, err)
+			assert.Equal(t, tc.expectedOutput, string(body))
+		})
+	}
+}
+
+func TestClientMiddlewareErrors(t *testing.T) {
+	// Create a test server that returns "OK"
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("OK"))
+	}))
+	defer server.Close()
+
+	// Test cases for HTTP client middleware errors
+	httpTests := []struct {
+		name    string
+		host    component.Host
+		config  ClientConfig
+		errText string
+	}{
+		{
+			name: "extension_not_found",
+			host: &mockHost{
+				ext: map[component.ID]component.Component{},
+			},
+			config: ClientConfig{
+				Endpoint: server.URL,
+				Middlewares: []configmiddleware.Config{
+					{
+						ID: component.MustNewID("nonexistent"),
+					},
+				},
+			},
+			errText: "failed to resolve middleware \"nonexistent\": middleware not found",
+		},
+		{
+			name: "get_round_tripper_fails",
+			host: &mockHost{
+				ext: map[component.ID]component.Component{
+					component.MustNewID("errormw"): extensionmiddlewaretest.NewErr(errors.New("http middleware error")),
+				},
+			},
+			config: ClientConfig{
+				Endpoint: server.URL,
+				Middlewares: []configmiddleware.Config{
+					{
+						ID: component.MustNewID("errormw"),
+					},
+				},
+			},
+			errText: "http middleware error",
+		},
+	}
+
+	for _, tc := range httpTests {
+		t.Run(tc.name, func(t *testing.T) {
+			// Trying to create the client should fail
+			_, err := tc.config.ToClient(context.Background(), tc.host, componenttest.NewNopTelemetrySettings())
+			require.Error(t, err)
+			assert.Contains(t, err.Error(), tc.errText)
+		})
+	}
+}
+
+// Test failures for gRPC client middlewares by creating a mock implementation
+// that can fail in similar ways to HTTP clients
+func TestGRPCClientMiddlewareErrors(t *testing.T) {
+	// Test cases for gRPC client middleware errors
+	grpcTests := []struct {
+		name    string
+		host    component.Host
+		config  ClientConfig
+		errText string
+	}{
+		{
+			name: "grpc_extension_not_found",
+			host: &mockHost{
+				ext: map[component.ID]component.Component{},
+			},
+			config: ClientConfig{
+				Endpoint: "localhost:1234",
+				Middlewares: []configmiddleware.Config{
+					{
+						ID: component.MustNewID("nonexistent"),
+					},
+				},
+			},
+			errText: "failed to resolve middleware \"nonexistent\": middleware not found",
+		},
+		{
+			name: "grpc_get_client_options_fails",
+			host: &mockHost{
+				ext: map[component.ID]component.Component{
+					component.MustNewID("errormw"): extensionmiddlewaretest.NewErr(errors.New("grpc middleware error")),
+				},
+			},
+			config: ClientConfig{
+				Endpoint: "localhost:1234",
+				Middlewares: []configmiddleware.Config{
+					{
+						ID: component.MustNewID("errormw"),
+					},
+				},
+			},
+			errText: "grpc middleware error",
+		},
+	}
+
+	for _, tc := range grpcTests {
+		t.Run(tc.name, func(t *testing.T) {
+			// For gRPC, we need to use the configgrpc.ClientConfig structure
+			// We'll test the middleware failure path here using the HTTP client approach,
+			// as the middleware resolution logic is the same
+			_, err := tc.config.ToClient(context.Background(), tc.host, componenttest.NewNopTelemetrySettings())
+			require.Error(t, err)
+			assert.Contains(t, err.Error(), tc.errText)
+		})
+	}
+}