[pkg/config/configmiddleware] Migrate middleware config to schema based (#15440)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

Use `metadata.yaml` schema to generate go code and json schema for
middleware config.

Author: jkoronaAtCisco

.chloggen/schema_based_configmiddlewarew.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. receiver/otlp)
+component: pkg/config/configmiddleware
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Migrated middleware config to schema based
+
+# One or more tracking issues or pull requests related to the change
+issues: [15440]
+
+# (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: [api]

config/configmiddleware/config.schema.json

@@ -0,0 +1,17 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "go.opentelemetry.io/collector/config/configmiddleware",
+  "title": "pkg/config/configmiddleware",
+  "$defs": {
+    "config": {
+      "description": "Defines the extension ID for a middleware component.",
+      "type": "object",
+      "properties": {
+        "id": {
+          "description": "Specifies the name of the extension to use.",
+          "type": "string"
+        }
+      }
+    }
+  }
+}

config/configmiddleware/configmiddleware.go

@@ -24,14 +24,6 @@ var (
 	errNotGRPCClient      = errors.New("requested extension is not a gRPC client middleware")
 )
 
-// Middleware defines the extension ID for a middleware component.
-type Config struct {
-	// ID specifies the name of the extension to use.
-	ID component.ID `mapstructure:"id,omitempty"`
-	// prevent unkeyed literal initialization
-	_ struct{}
-}
-
 // GetHTTPClientRoundTripper attempts to select the appropriate
 // extensionmiddleware.HTTPClient from the map of extensions, and
 // returns the HTTP client wrapper function. If a middleware is not

config/configmiddleware/generated_config.go

@@ -8,6 +8,7 @@ require (
 	go.opentelemetry.io/collector/extension v1.60.0
 	go.opentelemetry.io/collector/extension/extensionmiddleware v0.154.0
 	go.opentelemetry.io/collector/extension/extensionmiddleware/extensionmiddlewaretest v0.154.0
+	go.uber.org/goleak v1.3.0
 	google.golang.org/grpc v1.81.1
 )
 

config/configmiddleware/generated_config_test.go

@@ -5,3 +5,13 @@ github_project: open-telemetry/opentelemetry-collector
 status:
   disable_codecov_badge: true
   class: pkg
+
+exported_configs:
+  config:
+    description: Defines the extension ID for a middleware component.
+    type: object
+    properties:
+      id:
+        description: Specifies the name of the extension to use.
+        type: string
+        x-customType: go.opentelemetry.io/collector/component.ID