chore: make metadata access type safe

Signed-off-by: Armando Ruocco <armando.ruocco@enterprisedb.com>

internal/cnpgi/instance/backup.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"os"
-	"strconv"
 	"time"
 
 	barmanBackup "github.com/cloudnative-pg/barman-cloud/pkg/backup"
@@ -20,7 +19,6 @@ import (
 
 	barmancloudv1 "github.com/cloudnative-pg/plugin-barman-cloud/api/v1"
 	"github.com/cloudnative-pg/plugin-barman-cloud/internal/cnpgi/common"
-	"github.com/cloudnative-pg/plugin-barman-cloud/internal/cnpgi/metadata"
 	"github.com/cloudnative-pg/plugin-barman-cloud/internal/cnpgi/operator/config"
 )
 
@@ -148,13 +146,6 @@ func (b BackupServiceImplementation) Backup(
 		EndLsn:     executedBackupInfo.EndLSN,
 		InstanceId: b.InstanceName,
 		Online:     true,
-		Metadata: map[string]string{
-			"timeline":    strconv.Itoa(executedBackupInfo.TimeLine),
-			"version":     metadata.Data.Version,
-			"name":        metadata.Data.Name,
-			"displayName": metadata.Data.DisplayName,
-			"clusterUID":  string(configuration.Cluster.ObjectMeta.UID),
-			"pluginName":  metadata.PluginName,
-		},
+		Metadata:   newBackupResultMetadata(configuration.Cluster.ObjectMeta.UID, executedBackupInfo.TimeLine).toMap(),
 	}, nil
 }

internal/cnpgi/instance/retention.go

@@ -279,6 +279,7 @@ func useSameBackupLocation(backup *cnpgv1.BackupStatus, cluster *cnpgv1.Cluster)
 		return false
 	}
 
-	return backup.PluginMetadata["clusterUID"] == string(cluster.UID) &&
-		backup.PluginMetadata["pluginName"] == metadata.PluginName
+	meta := newBackupResultMetadataFromMap(backup.PluginMetadata)
+
+	return meta.clusterUID == string(cluster.UID) && meta.pluginName == metadata.PluginName
 }

internal/cnpgi/instance/types.go

@@ -0,0 +1,56 @@
+package instance
+
+import (
+	"strconv"
+
+	"k8s.io/apimachinery/pkg/types"
+
+	"github.com/cloudnative-pg/plugin-barman-cloud/internal/cnpgi/metadata"
+)
+
+type backupResultMetadata struct {
+	timeline    string
+	version     string
+	name        string
+	displayName string
+	clusterUID  string
+	pluginName  string
+}
+
+func (b backupResultMetadata) toMap() map[string]string {
+	return map[string]string{
+		"timeline":    b.timeline,
+		"version":     b.version,
+		"name":        b.name,
+		"displayName": b.displayName,
+		"clusterUID":  b.clusterUID,
+		"pluginName":  b.pluginName,
+	}
+}
+
+func newBackupResultMetadata(clusterUID types.UID, timeline int) backupResultMetadata {
+	return backupResultMetadata{
+		timeline:   strconv.Itoa(timeline),
+		clusterUID: string(clusterUID),
+		// static values
+		version:     metadata.Data.Version,
+		name:        metadata.Data.Name,
+		displayName: metadata.Data.DisplayName,
+		pluginName:  metadata.PluginName,
+	}
+}
+
+func newBackupResultMetadataFromMap(m map[string]string) backupResultMetadata {
+	if m == nil {
+		return backupResultMetadata{}
+	}
+
+	return backupResultMetadata{
+		timeline:    m["timeline"],
+		version:     m["version"],
+		name:        m["name"],
+		displayName: m["displayName"],
+		clusterUID:  m["clusterUID"],
+		pluginName:  m["pluginName"],
+	}
+}