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https://issues.apache.org/jira/browse/FLINK-12086?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16808282#comment-16808282
]
Guowei Ma edited comment on FLINK-12086 at 4/3/19 1:30 AM:
-----------------------------------------------------------
I think there might be another way to access user object other than change the
API.
{code:java}
package dev.codeflush;
import org.apache.flink.streaming.api.functions.async.AsyncFunction;
import org.apache.flink.streaming.api.functions.async.ResultFuture;
import java.util.Collections;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
public class SomeAsyncFunction implements AsyncFunction<Integer, String> {
private static final long serialVersionUID = 1L;
private HashMap<ResultFuture<String>, Future<String>> libFutures = new
HashMap();
@Override
public void asyncInvoke(Integer input, ResultFuture<String> resultFuture)
throws Exception {
Future<String> future = null; // submit something in a library
thread-pool
libFutures.put(resultFuture, future);
CompletableFuture.runAsync(() -> {
try {
resultFuture.complete(Collections.singleton(future.get()));
libFutures.remove(resultFuture);
} catch (ExecutionException e) {
// handle this
} catch (InterruptedException e) {
// handle that
}
});
return future;
}
@Override
public void timeout(Integer input, ResultFuture<String> resultFuture)
throws Exception {
Future<String> future = libFutures.remove(resultFuture);
if (future != null) {
future.cancel(true);
}
resultFuture.complete(Collections.emptySet());
}
}
{code}
was (Author: maguowei):
I think there might be another way to access user object other than change the
API.
{code:java}
package dev.codeflush;
import org.apache.flink.streaming.api.functions.async.AsyncFunction;
import org.apache.flink.streaming.api.functions.async.ResultFuture;
import java.util.Collections;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
public class SomeAsyncFunction implements AsyncFunction<Integer, String> {
private static final long serialVersionUID = 1L;
private HashMap<ResultFuture<String>, Future<String>> libFutures = new
HashMap();
@Override
public void asyncInvoke(Integer input, ResultFuture<String> resultFuture)
throws Exception {
Future<String> future = null; // submit something in a library
thread-pool
libFutures.put(resultFuture, future);
CompletableFuture.runAsync(() -> {
try {
resultFuture.complete(Collections.singleton(future.get()));
libFutures.remove(resultFuture);
} catch (ExecutionException e) {
// handle this
} catch (InterruptedException e) {
// handle that
}
});
return future;
}
@Override
public void timeout(Integer input, ResultFuture<String> resultFuture)
throws Exception {
Future<String> future = libFutures.remove(resultFuture);
if (future != null) {
future.cancel(true);
}
resultFuture.complete(Collections.emptySet());
}
}
{code}
> AsyncFunction - Add access to a user defined Object for cleanup on timeout
> --------------------------------------------------------------------------
>
> Key: FLINK-12086
> URL: https://issues.apache.org/jira/browse/FLINK-12086
> Project: Flink
> Issue Type: Improvement
> Components: API / DataStream
> Reporter: Felix Wollschläger
> Priority: Major
>
> When executing async-requests it would be nice to have access to a user
> defined object to perform cleanup when the process times out.
> For example, when executing Cassandra-Queries I'm using the drivers
> threadpool to submit Statements, which returns a
> com.datastax.driver.core.ResultSetFutre (
> [https://docs.datastax.com/en/drivers/java/2.1/com/datastax/driver/core/ResultSetFuture.html]
> ). When I run into a timeout I could cancel the Future because waiting for
> it to complete is unnecessary in that case.
>
> The API could be extendend to something like this:
>
> Adding an Type-Parameter to the AsnyFunction Interface:
> {code:java}
> AsyncFunction<IN, OUT, T>{code}
> Updating the asnyInvoke-Method to return the user-defined object:
> {code:java}
> T asyncInvoke(IN input, ResultFuture<OUT> future) throws Exception;{code}
> Updating the timeout-Method to accept the user-defined object:
> {code:java}
> void timeout(IN input, T obj, ResultFuture<OUT> resultFuture) throws
> Exception{code}
>
> An example Implementation could look like this:
> {code:java}
> package dev.codeflush;
> import org.apache.flink.streaming.api.functions.async.AsyncFunction;
> import org.apache.flink.streaming.api.functions.async.ResultFuture;
> import java.util.Collections;
> import java.util.concurrent.CompletableFuture;
> import java.util.concurrent.ExecutionException;
> import java.util.concurrent.Future;
> public class SomeAsyncFunction implements AsyncFunction<Integer, String,
> Future<String>> {
> private static final long serialVersionUID = 1L;
>
> @Override
> public Future<String> asyncInvoke(Integer input, ResultFuture<String>
> resultFuture) throws Exception {
> Future<String> future = null; // submit something in a library
> thread-pool
> CompletableFuture.runAsync(() -> {
> try {
> resultFuture.complete(Collections.singleton(future.get()));
> } catch (ExecutionException e) {
> // handle this
> } catch (InterruptedException e) {
> // handle that
> }
> });
>
> return future;
> }
> @Override
> public void timeout(Integer input, Future<String> future,
> ResultFuture<String> resultFuture) throws Exception {
> future.cancel(true);
> resultFuture.complete(Collections.emptySet());
> }
> }
> {code}
> As it currently is, submitted tasks in the asnyInvoke-Method will use
> resources (Threads, IO) even if the application is no longer in a state where
> it could do something meaningful with the result.
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