public CompletableFuture<Long> readMetricsValue(MetricsCondition condition, Duration duration) {
        return queryAsync(() -> {
            if (!condition.senseScope() || !condition.getEntity().isValid()) {
                return 0L;
            }
            return getMetricsQueryService().readMetricsValue(condition, duration).getValue();
        });
    }
Read metrics single value in the duration of required metrics
oap-server/server-query-plugin/query-graphql-plugin/src/main/java/org/apache/skywalking/oap/query/graphql/resolver/MetricsQuery.java