feat(observability): add maintenance policy metrics

Prometheus: runs, duration, rows_deleted, config_changes; инкремент при CRUD и Execute.
Co-authored-by: Cursor <[email protected]>

internal/maintenance/policy_executor.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"evobgp/internal/observability"
 	"evobgp/internal/pgmonitor"
 	"evobgp/internal/store"
 
@@ -22,19 +23,29 @@ type PolicyExecutor struct {
 
 // Execute runs cleanup and/or vacuum steps for a policy.
 func (e *PolicyExecutor) Execute(ctx context.Context, policy *store.MaintenancePolicy, dryRun bool) (map[string]any, error) {
-	if e == nil || e.Pool == nil {
-		return nil, fmt.Errorf("maintenance: postgres not configured")
-	}
+	start := time.Now()
 	if policy == nil {
 		return nil, store.ErrInvalidInput
 	}
+	action := policyAction(policy)
+	record := func(status string, detail map[string]any) {
+		observability.RecordMaintenancePolicyRun(policy.ID, action, status, dryRun, time.Since(start), rowsDeletedFromDetail(detail))
+	}
+
+	if e == nil || e.Pool == nil {
+		record("failed", nil)
+		return nil, fmt.Errorf("maintenance: postgres not configured")
+	}
 	if err := ValidateTableName(policy.TableName); err != nil {
+		record("failed", nil)
 		return nil, err
 	}
 	if err := ValidateCondition(policy.Condition); err != nil {
+		record("failed", nil)
 		return nil, err
 	}
 	if !store.ValidVacuumStrategy(policy.VacuumStrategy) {
+		record("failed", nil)
 		return nil, store.ErrInvalidInput
 	}
 
@@ -50,6 +61,7 @@ func (e *PolicyExecutor) Execute(ctx context.Context, policy *store.MaintenanceP
 			detail[k] = v
 		}
 		if err != nil {
+			record("failed", detail)
 			return detail, err
 		}
 	}
@@ -61,6 +73,7 @@ func (e *PolicyExecutor) Execute(ctx context.Context, policy *store.MaintenanceP
 			detail["vacuum"] = vacDetail
 		}
 		if err != nil {
+			record("failed", detail)
 			return detail, err
 		}
 	}
@@ -68,10 +81,42 @@ func (e *PolicyExecutor) Execute(ctx context.Context, policy *store.MaintenanceP
 	if !dryRun && e.Store != nil {
 		_ = e.Store.TouchMaintenancePolicyRun(policy.ID, "succeeded", "")
 	}
-
+	record("succeeded", detail)
 	return detail, nil
 }
 
+func policyAction(p *store.MaintenancePolicy) string {
+	if p == nil {
+		return "run"
+	}
+	if p.RetentionPeriodSec != nil || p.MaxRows != nil {
+		if p.VacuumStrategy != store.VacuumStrategyNone {
+			return "cleanup_vacuum"
+		}
+		return "cleanup"
+	}
+	if p.VacuumStrategy != store.VacuumStrategyNone {
+		return p.VacuumStrategy
+	}
+	return "run"
+}
+
+func rowsDeletedFromDetail(detail map[string]any) int64 {
+	if detail == nil {
+		return 0
+	}
+	switch v := detail["deleted"].(type) {
+	case int64:
+		return v
+	case int:
+		return int64(v)
+	case float64:
+		return int64(v)
+	default:
+		return 0
+	}
+}
+
 func (e *PolicyExecutor) runCleanup(ctx context.Context, policy *store.MaintenancePolicy, dryRun bool) (map[string]any, error) {
 	detail := map[string]any{"cleanup": true}
 	limit := NormalizeBatchLimit(policy.MaxRows)