Can I write sync code in RichAsyncFunction

Question

When I need to work with I/O (Query DB, Call to the third API,...), I can use RichAsyncFunction. But I need to interact with Google Sheet via GG Sheet API: https://developers.google.com/sheets/api/quickstart/java. This API is sync. I wrote below code snippet:

public class SendGGSheetFunction extends RichAsyncFunction<Obj, String> {

    @Override
    public void asyncInvoke(Obj message, final ResultFuture<String> resultFuture) {
        CompletableFuture.supplyAsync(() -> {
            syncSendToGGSheet(message);
            return "";
        }).thenAccept((String result) -> {
            resultFuture.complete(Collections.singleton(result));
        });
    }

}

But I found that message send to GGSheet very slow, It seems to send by synchronous.

Answer 1

Most of the code executed by users in AsyncIO is sync originally. You just need to ensure, it's actually executed in a separate thread. Most commonly a (statically shared) ExecutorService is used.

private class SendGGSheetFunction extends RichAsyncFunction<Obj, String> {
   private transient ExecutorService executorService;

   @Override
   public void open(Configuration parameters) throws Exception {
      super.open(parameters);
      executorService = Executors.newFixedThreadPool(30);
   }

   @Override
   public void close() throws Exception {
      super.close();
      executorService.shutdownNow();
   }

   @Override
   public void asyncInvoke(final Obj message, final ResultFuture<String> resultFuture) {
      executorService.submit(() -> {
         try {
            resultFuture.complete(syncSendToGGSheet(message));
         } catch (SQLException e) {
            resultFuture.completeExceptionally(e);
         }
      });
   }
}

Here are some considerations on how to tune AsyncIO to increase throughput: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Flink-Async-IO-operator-tuning-micro-benchmarks-td35858.html