feat(a1): Implement O-RAN Policy Status Reporting (Task #62)

deployments/xapps/scaling-xapp/README.md

@@ -173,3 +173,81 @@ kubectl logs -n ricxapp deployment/ricxapp-scaling
 | K8s API | ❌ 不直接調用 | ✅ 直接調用 |
 | RMR Messaging | ✅ 使用 | ❌ 不使用 |
 
+
+## Policy Status Reporting (O-RAN A1-P v2 標準)
+
+### 概述
+
+Scaling xApp 完全符合 O-RAN A1-P v2 規範，自動向 A1 Mediator 報告每個 policy 的執行狀態。
+
+### 狀態類型
+
+- **ENFORCED**: Policy 成功執行，Deployment 已按要求擴展
+- **NOT_ENFORCED**: Policy 無法執行（Deployment 不存在或操作失敗）
+
+### API 規格
+
+```
+POST /A1-P/v2/policytypes/100/policies/{policyId}/status
+Content-Type: application/json
+
+{
+  "enforceStatus": "ENFORCED" | "NOT_ENFORCED",
+  "enforceReason": "Human-readable reason string"
+}
+```
+
+### 示例
+
+#### 成功情況
+```json
+{
+  "enforceStatus": "ENFORCED",
+  "enforceReason": "Successfully scaled ran-a/nf-sim to 5 replicas"
+}
+```
+
+#### 失敗情況
+```json
+{
+  "enforceStatus": "NOT_ENFORCED",
+  "enforceReason": "Failed to scale default/nonexistent: deployments.apps \"nonexistent\" not found"
+}
+```
+
+### Metrics
+
+Policy Status Reporting 暴露專用 metrics：
+
+```promql
+# 狀態報告總數（按狀態和結果分類）
+scaling_xapp_policy_status_reports_total{enforce_status, result}
+
+# Labels:
+# - enforce_status: "ENFORCED", "NOT_ENFORCED"
+# - result: "success", "network_error", "http_error", "marshal_error"
+```
+
+### 日誌
+
+```
+2026-02-24T10:00:30Z INFO 📊 Policy status reported: policy-test-scale-to-5 → ENFORCED (HTTP 200)
+2026-02-24T10:00:31Z INFO 📊 Policy status reported: policy-invalid → NOT_ENFORCED (HTTP 200)
+```
+
+### 故障處理
+
+狀態報告失敗**不會**影響 scaling 操作本身：
+
+- Scaling 成功 → 嘗試報告 ENFORCED（即使報告失敗，deployment 已擴展）
+- Scaling 失敗 → 嘗試報告 NOT_ENFORCED
+
+所有狀態報告失敗都會記錄在日誌和 metrics 中。
+
+### O-RAN 合規性
+
+- ✅ 符合 O-RAN.WG2.A1AP-v03.01 規範
+- ✅ 支持 A1-P v2 API
+- ✅ 自動狀態報告（無需手動觸發）
+- ✅ 提供詳細的執行原因 (enforceReason)
+

deployments/xapps/scaling-xapp/main.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"os"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -38,6 +39,14 @@ var (
 		[]string{"method", "status_code"},
 	)
 
+	policyStatusReports = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "scaling_xapp_policy_status_reports_total",
+			Help: "Total number of policy status reports sent to A1 Mediator",
+		},
+		[]string{"enforce_status", "result"},
+	)
+
 	// Gauges
 	activePolicies = promauto.NewGauge(
 		prometheus.GaugeOpts{
@@ -103,6 +112,12 @@ type ScalingSpec struct {
 	Source     string `json:"source"`
 }
 
+// PolicyStatus represents the status report sent to A1 Mediator
+type PolicyStatus struct {
+	EnforceStatus string `json:"enforceStatus"` // "ENFORCED" or "NOT_ENFORCED"
+	EnforceReason string `json:"enforceReason"` // Human-readable reason
+}
+
 type ScalingXApp struct {
 	k8sClient    *kubernetes.Clientset
 	a1URL        string
@@ -258,8 +273,22 @@ func (x *ScalingXApp) executePolicy(ctx context.Context, policyID string) error
 	log.Printf("Executing scaling policy: %s (target=%s, namespace=%s, replicas=%d)",
 		policyID, spec.Target, spec.Namespace, spec.Replicas)
 
-	// Execute the scaling action
-	return x.scaleDeployment(ctx, spec)
+	// Execute the scaling action and report status
+	err = x.scaleDeployment(ctx, spec)
+
+	// Report policy status to A1 Mediator
+	if err != nil {
+		// Failed - report NOT_ENFORCED
+		reason := fmt.Sprintf("Failed to scale %s/%s: %v", spec.Namespace, spec.Target, err)
+		x.reportPolicyStatus(policyID, false, reason)
+		return err
+	}
+
+	// Success - report ENFORCED
+	reason := fmt.Sprintf("Successfully scaled %s/%s to %d replicas", spec.Namespace, spec.Target, spec.Replicas)
+	x.reportPolicyStatus(policyID, true, reason)
+
+	return nil
 }
 
 func (x *ScalingXApp) scaleDeployment(ctx context.Context, spec ScalingSpec) error {
@@ -301,6 +330,53 @@ func (x *ScalingXApp) scaleDeployment(ctx context.Context, spec ScalingSpec) err
 	return nil
 }
 
+// reportPolicyStatus reports policy enforcement status to A1 Mediator
+func (x *ScalingXApp) reportPolicyStatus(policyID string, enforced bool, reason string) {
+	start := time.Now()
+	defer func() {
+		a1RequestDuration.WithLabelValues("POST_STATUS").Observe(time.Since(start).Seconds())
+	}()
+
+	// Prepare status payload
+	status := PolicyStatus{
+		EnforceStatus: "NOT_ENFORCED",
+		EnforceReason: reason,
+	}
+	if enforced {
+		status.EnforceStatus = "ENFORCED"
+	}
+
+	statusJSON, err := json.Marshal(status)
+	if err != nil {
+		log.Printf("Failed to marshal policy status for %s: %v", policyID, err)
+		policyStatusReports.WithLabelValues(status.EnforceStatus, "marshal_error").Inc()
+		return
+	}
+
+	// Send status to A1 Mediator
+	url := fmt.Sprintf("%s/A1-P/v2/policytypes/100/policies/%s/status", x.a1URL, policyID)
+
+	resp, err := http.Post(url, "application/json", strings.NewReader(string(statusJSON)))
+	if err != nil {
+		log.Printf("Failed to report status for policy %s: %v", policyID, err)
+		a1Requests.WithLabelValues("POST", "error").Inc()
+		policyStatusReports.WithLabelValues(status.EnforceStatus, "network_error").Inc()
+		return
+	}
+	defer resp.Body.Close()
+
+	a1Requests.WithLabelValues("POST", strconv.Itoa(resp.StatusCode)).Inc()
+
+	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+		log.Printf("📊 Policy status reported: %s → %s (HTTP %d)",
+			policyID, status.EnforceStatus, resp.StatusCode)
+		policyStatusReports.WithLabelValues(status.EnforceStatus, "success").Inc()
+	} else {
+		log.Printf("Failed to report policy status for %s: HTTP %d", policyID, resp.StatusCode)
+		policyStatusReports.WithLabelValues(status.EnforceStatus, "http_error").Inc()
+	}
+}
+
 func main() {
 	// Start metrics server
 	go func() {