fix: possible panics in tracedb package

server/tracedb/azureappinsights.go

@@ -214,6 +214,10 @@ func parseSpans(table *azquery.Table) ([]traces.Span, error) {
 
 	for _, eventRow := range eventRows {
 		parentSpan := spanMap[eventRow.ParentID()]
+		if parentSpan == nil {
+			continue
+		}
+
 		event, err := parseEvent(eventRow)
 		if err != nil {
 			return []traces.Span{}, err

server/tracedb/elasticsearchdb.go

@@ -137,6 +137,11 @@ func getClusterInfo(client *elasticsearch.Client) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("error getting cluster info response: %s", err)
 	}
+
+	if res == nil {
+		return "", fmt.Errorf("could not get response")
+	}
+
 	defer res.Body.Close()
 
 	// Check response status

server/tracedb/signalfxdb.go

@@ -114,6 +114,10 @@ func (db signalfxDB) getSegmentsTimestamps(ctx context.Context, traceID string)
 		return []int64{}, fmt.Errorf("could not execute request: %w", err)
 	}
 
+	if response == nil {
+		return []int64{}, fmt.Errorf("could not get response")
+	}
+
 	if response.StatusCode != http.StatusOK {
 		return []int64{}, fmt.Errorf("service responded with a non ok status code: %s", strconv.Itoa(response.StatusCode))
 	}
@@ -148,6 +152,10 @@ func (db signalfxDB) getSegmentSpans(ctx context.Context, traceID string, timest
 		return []signalFXSpan{}, fmt.Errorf("could not execute request: %w", err)
 	}
 
+	if response == nil {
+		return []signalFXSpan{}, fmt.Errorf("could not get response")
+	}
+
 	if response.StatusCode != 200 {
 		return []signalFXSpan{}, nil
 	}

server/tracedb/tempodb.go

@@ -121,11 +121,14 @@ func httpGetTraceByID(ctx context.Context, traceID string, client *datasource.Ht
 		return traces.Trace{}, err
 	}
 	resp, err := client.Request(ctx, fmt.Sprintf("/api/traces/%s", trID), http.MethodGet, "")
-
 	if err != nil {
 		return traces.Trace{}, handleError(err)
 	}
 
+	if resp == nil {
+		return traces.Trace{}, fmt.Errorf("could not get response")
+	}
+
 	if resp.StatusCode == 404 {
 		return traces.Trace{}, connection.ErrTraceNotFound
 	}