osbuild-service-maintenance/aws: merge errors

Collect and merge errors, instead of
nesting errors.
In this case we want to continue execution if only one
cleanup fails.

cmd/osbuild-service-maintenance/aws.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"slices"
+	"strings"
 	"sync"
 	"time"
 
@@ -19,6 +20,27 @@ type ChildToParentAssociation struct {
 	Parent string
 }
 
+type MultiError struct {
+	Errors []error
+}
+
+// Append adds a new error to the MultiError if non-nil
+func (m *MultiError) Append(err error) {
+	if err != nil {
+		m.Errors = append(m.Errors, err)
+	}
+}
+
+// Error implements the error interface for MultiError
+// which joins them with semicolon
+func (m MultiError) Error() string {
+	var messages []string
+	for _, err := range m.Errors {
+		messages = append(messages, err.Error())
+	}
+	return strings.Join(messages, "; ")
+}
+
 func AWSCleanup(maxConcurrentRequests int, dryRun bool, accessKeyID, accessKey string, cutoff time.Time) error {
 	const region = "us-east-1"
 	var a *awscloud.AWS
@@ -104,33 +126,29 @@ func AWSCleanup(maxConcurrentRequests int, dryRun bool, accessKeyID, accessKey s
 		wg.Wait()
 	}
 
-	// using err to collect both errors as we want to
-	// continue execution if one cleanup fails
-	err = nil
-	errSecureInstances := terminateOrphanedSecureInstances(a, dryRun)
-	// keep going with other cleanup even on error
-	if errSecureInstances != nil {
-		logrus.Errorf("Error in terminating secure instances: %v, continuing other cleanup.", errSecureInstances)
-		err = errSecureInstances
+	// using `errors` to collect all errors as we want to
+	// continue execution if only one cleanup fails
+	var errors MultiError
+
+	err = terminateOrphanedSecureInstances(a, dryRun)
+	if err != nil {
+		logrus.Errorf("Error in terminating secure instances: %v, continuing other cleanup.", err)
+		errors.Append(err)
 	}
 
-	errSecurityGroups := searchSGAndCleanup(ctx, a, dryRun)
-	if errSecurityGroups != nil {
-		logrus.Errorf("Error in cleaning up security groups: %v", errSecurityGroups)
-		if err != nil {
-			err = fmt.Errorf("Multiple errors while processing AWSCleanup: %w and %w.", err, errSecurityGroups)
-		}
+	err = searchSGAndCleanup(ctx, a, dryRun)
+	if err != nil {
+		logrus.Errorf("Error in cleaning up security groups: %v", err)
+		errors.Append(err)
 	}
 
-	errLaunchTemplates := searchLTAndCleanup(ctx, a, dryRun)
-	if errLaunchTemplates != nil {
-		logrus.Errorf("Error in cleaning up launch templates: %v", errLaunchTemplates)
-		if err != nil {
-			err = fmt.Errorf("Multiple errors while processing AWSCleanup: %w and %w.", err, errLaunchTemplates)
-		}
+	err = searchLTAndCleanup(ctx, a, dryRun)
+	if err != nil {
+		logrus.Errorf("Error in cleaning up launch templates: %v", err)
+		errors.Append(err)
 	}
 
-	return err
+	return errors
 }
 
 func terminateOrphanedSecureInstances(a *awscloud.AWS, dryRun bool) error {