fix(storage): resolve race condition in memory store (#1270)

* fix(storage): resolve race condition in memory store

* fix: resolve variable shadowing in CopyEndpointStatus

* fix: update test files to use CopyEndpointStatus function

Author: TwiN

storage/store/memory/memory.go

@@ -49,7 +49,7 @@ func (s *Store) GetAllEndpointStatuses(params *paging.EndpointStatusParams) ([]*
 	pagedEndpointStatuses := make([]*endpoint.Status, 0, len(allStatuses))
 	for _, v := range allStatuses {
 		if status, ok := v.(*endpoint.Status); ok {
-			pagedEndpointStatuses = append(pagedEndpointStatuses, ShallowCopyEndpointStatus(status, params))
+			pagedEndpointStatuses = append(pagedEndpointStatuses, CopyEndpointStatus(status, params))
 		}
 	}
 	sort.Slice(pagedEndpointStatuses, func(i, j int) bool {
@@ -87,7 +87,7 @@ func (s *Store) GetEndpointStatusByKey(key string, params *paging.EndpointStatus
 	if endpointStatus == nil {
 		return nil, common.ErrEndpointNotFound
 	}
-	return ShallowCopyEndpointStatus(endpointStatus.(*endpoint.Status), params), nil
+	return CopyEndpointStatus(endpointStatus.(*endpoint.Status), params), nil
 }
 
 // GetSuiteStatusByKey returns the suite status for a given key

storage/store/memory/util.go

@@ -6,35 +6,47 @@ import (
 	"github.com/TwiN/gatus/v5/storage/store/common/paging"
 )
 
-// ShallowCopyEndpointStatus returns a shallow copy of a Status with only the results
-// within the range defined by the page and pageSize parameters
-func ShallowCopyEndpointStatus(ss *endpoint.Status, params *paging.EndpointStatusParams) *endpoint.Status {
-	shallowCopy := &endpoint.Status{
+// CopyEndpointStatus returns a safe copy of a Status with only the results
+// within the range defined by the page and pageSize parameters.
+// This function performs deep copying of slices to prevent race conditions
+// when the original slice is modified concurrently.
+func CopyEndpointStatus(ss *endpoint.Status, params *paging.EndpointStatusParams) *endpoint.Status {
+	statusCopy := &endpoint.Status{
 		Name:   ss.Name,
 		Group:  ss.Group,
 		Key:    ss.Key,
 		Uptime: endpoint.NewUptime(),
 	}
 	if params == nil || (params.ResultsPage == 0 && params.ResultsPageSize == 0 && params.EventsPage == 0 && params.EventsPageSize == 0) {
-		shallowCopy.Results = ss.Results
-		shallowCopy.Events = ss.Events
+		// Deep copy all results to prevent race conditions
+		statusCopy.Results = make([]*endpoint.Result, len(ss.Results))
+		copy(statusCopy.Results, ss.Results)
+		// Deep copy all events to prevent race conditions
+		statusCopy.Events = make([]*endpoint.Event, len(ss.Events))
+		copy(statusCopy.Events, ss.Events)
 	} else {
 		numberOfResults := len(ss.Results)
 		resultsStart, resultsEnd := getStartAndEndIndex(numberOfResults, params.ResultsPage, params.ResultsPageSize)
 		if resultsStart < 0 || resultsEnd < 0 {
-			shallowCopy.Results = []*endpoint.Result{}
+			statusCopy.Results = []*endpoint.Result{}
 		} else {
-			shallowCopy.Results = ss.Results[resultsStart:resultsEnd]
+			// Deep copy the slice range to prevent race conditions
+			resultRange := ss.Results[resultsStart:resultsEnd]
+			statusCopy.Results = make([]*endpoint.Result, len(resultRange))
+			copy(statusCopy.Results, resultRange)
 		}
 		numberOfEvents := len(ss.Events)
 		eventsStart, eventsEnd := getStartAndEndIndex(numberOfEvents, params.EventsPage, params.EventsPageSize)
 		if eventsStart < 0 || eventsEnd < 0 {
-			shallowCopy.Events = []*endpoint.Event{}
+			statusCopy.Events = []*endpoint.Event{}
 		} else {
-			shallowCopy.Events = ss.Events[eventsStart:eventsEnd]
+			// Deep copy the slice range to prevent race conditions
+			eventRange := ss.Events[eventsStart:eventsEnd]
+			statusCopy.Events = make([]*endpoint.Event, len(eventRange))
+			copy(statusCopy.Events, eventRange)
 		}
 	}
-	return shallowCopy
+	return statusCopy
 }
 
 // ShallowCopySuiteStatus returns a shallow copy of a suite Status with only the results

storage/store/memory/util_bench_test.go

@@ -8,14 +8,14 @@ import (
 	"github.com/TwiN/gatus/v5/storage/store/common/paging"
 )
 
-func BenchmarkShallowCopyEndpointStatus(b *testing.B) {
+func BenchmarkCopyEndpointStatus(b *testing.B) {
 	ep := &testEndpoint
 	status := endpoint.NewStatus(ep.Group, ep.Name)
 	for i := 0; i < storage.DefaultMaximumNumberOfResults; i++ {
 		AddResult(status, &testSuccessfulResult, storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
 	}
 	for n := 0; n < b.N; n++ {
-		ShallowCopyEndpointStatus(status, paging.NewEndpointStatusParams().WithResults(1, 20))
+		CopyEndpointStatus(status, paging.NewEndpointStatusParams().WithResults(1, 20))
 	}
 	b.ReportAllocs()
 }

storage/store/memory/util_test.go

@@ -26,42 +26,42 @@ func TestAddResult(t *testing.T) {
 	AddResult(nil, &endpoint.Result{Timestamp: time.Now()}, storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
 }
 
-func TestShallowCopyEndpointStatus(t *testing.T) {
+func TestCopyEndpointStatus(t *testing.T) {
 	ep := &endpoint.Endpoint{Name: "name", Group: "group"}
 	endpointStatus := endpoint.NewStatus(ep.Group, ep.Name)
 	ts := time.Now().Add(-25 * time.Hour)
 	for i := 0; i < 25; i++ {
 		AddResult(endpointStatus, &endpoint.Result{Success: i%2 == 0, Timestamp: ts}, storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
 		ts = ts.Add(time.Hour)
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(-1, -1)).Results) != 0 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(-1, -1)).Results) != 0 {
 		t.Error("expected to have 0 result")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(1, 1)).Results) != 1 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(1, 1)).Results) != 1 {
 		t.Error("expected to have 1 result")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(5, 0)).Results) != 0 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(5, 0)).Results) != 0 {
 		t.Error("expected to have 0 results")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(-1, 20)).Results) != 0 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(-1, 20)).Results) != 0 {
 		t.Error("expected to have 0 result, because the page was invalid")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(1, -1)).Results) != 0 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(1, -1)).Results) != 0 {
 		t.Error("expected to have 0 result, because the page size was invalid")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(1, 10)).Results) != 10 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(1, 10)).Results) != 10 {
 		t.Error("expected to have 10 results, because given a page size of 10, page 1 should have 10 elements")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(2, 10)).Results) != 10 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(2, 10)).Results) != 10 {
 		t.Error("expected to have 10 results, because given a page size of 10, page 2 should have 10 elements")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(3, 10)).Results) != 5 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(3, 10)).Results) != 5 {
 		t.Error("expected to have 5 results, because given a page size of 10, page 3 should have 5 elements")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(4, 10)).Results) != 0 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(4, 10)).Results) != 0 {
 		t.Error("expected to have 0 results, because given a page size of 10, page 4 should have 0 elements")
 	}
-	if len(ShallowCopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(1, 50)).Results) != 25 {
+	if len(CopyEndpointStatus(endpointStatus, paging.NewEndpointStatusParams().WithResults(1, 50)).Results) != 25 {
 		t.Error("expected to have 25 results, because there's only 25 results")
 	}
 }