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Fix blocking calls #8

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Fix blocking calls #8

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93894bf
Move blocking publishChatMessage operation to boundedElastic thread
Arooba-git Jul 14, 2023
371c6a9
Update ChatWebSocketHandler to move blocking operations to boundedEla…
Arooba-git Jul 14, 2023
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17 changes: 11 additions & 6 deletions src/main/java/com/github/rawsanj/handler/ChatWebSocketHandler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import reactor.core.publisher.Sinks;
import reactor.core.scheduler.Schedulers;

@Slf4j
public class ChatWebSocketHandler implements WebSocketHandler {
Expand Down Expand Up @@ -40,15 +41,19 @@ public Mono<Void> handle(WebSocketSession webSocketSession) {
Mono<Void> inputMessage = webSocketSession.receive()
.flatMap(webSocketMessage -> redisChatMessagePublisher.publishChatMessage(webSocketMessage.getPayloadAsText()))
.doOnSubscribe(subscription -> {
long activeUserCount = activeUserCounter.incrementAndGet();
log.info("User '{}' Connected. Total Active Users: {}", webSocketSession.getId(), activeUserCount);
chatMessageSink.tryEmitNext(new ChatMessage(0, "CONNECTED", "CONNECTED", activeUserCount));
Mono.fromRunnable(() -> {
long activeUserCount = activeUserCounter.incrementAndGet();
log.info("User '{}' Connected. Total Active Users: {}", webSocketSession.getId(), activeUserCount);
chatMessageSink.tryEmitNext(new ChatMessage(0, "CONNECTED", "CONNECTED", activeUserCount));
}).subscribeOn(Schedulers.boundedElastic()).subscribe();
})
.doOnError(throwable -> log.error("Error Occurred while sending message to Redis.", throwable))
.doFinally(signalType -> {
long activeUserCount = activeUserCounter.decrementAndGet();
log.info("User '{}' Disconnected. Total Active Users: {}", webSocketSession.getId(), activeUserCount);
chatMessageSink.tryEmitNext(new ChatMessage(0, "DISCONNECTED", "DISCONNECTED", activeUserCount));
Mono.fromRunnable(() -> {
long activeUserCount = activeUserCounter.decrementAndGet();
log.info("User '{}' Disconnected. Total Active Users: {}", webSocketSession.getId(), activeUserCount);
chatMessageSink.tryEmitNext(new ChatMessage(0, "DISCONNECTED", "DISCONNECTED", activeUserCount));
}).subscribeOn(Schedulers.boundedElastic()).subscribe();
})
.then();

Expand Down
5 changes: 4 additions & 1 deletion src/main/java/com/github/rawsanj/handler/WebHttpHandler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
import org.springframework.http.MediaType;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.ServerResponse;
import reactor.core.scheduler.Schedulers;

import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
import static org.springframework.web.reactive.function.server.RequestPredicates.POST;
Expand All @@ -23,7 +24,9 @@ public RouterFunction<ServerResponse> htmlRouter(@Value("classpath:/static/index
return route(GET("/"), request -> ok().contentType(MediaType.TEXT_HTML).bodyValue(html))
.andRoute(POST("/message"), request -> request.bodyToMono(Message.class)
.flatMap(message -> redisChatMessagePublisher.publishChatMessage(message.getMessage()))
.flatMap(aLong -> ServerResponse.ok().bodyValue(new Message("Message Sent Successfully!."))));
.flatMap(aLong -> ServerResponse.ok().bodyValue(new Message("Message Sent Successfully!.")))
.subscribeOn(Schedulers.boundedElastic()));
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Do we really need to make this run on Schedulers.boundedElastic() Did the BlockHound detected blocking call over here or inside the RedisChatMessagePublisher?

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@Arooba-git Arooba-git Nov 29, 2023 •
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In the first stack trace (first screenshot in the post), we see that the error propagates to RedisChatMessagePublisher but was triggered by WebHttpHandler, line 26 right? :)

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In the first stack trace (first screenshot in the post), we see that the error propagates to RedisChatMessagePublisher but was triggered by WebHttpHandler, line 26 right? :)

The other way round. The actual blocking call is at line - https://github.com/RawSanj/spring-redis-websocket/blob/master/src/main/java/com/github/rawsanj/messaging/RedisChatMessagePublisher.java#L35C11-L35C28 the Atomic Increment is blocking.

I think we should be good if we move that blocking call Integer totalChatMessage = chatMessageCounter.incrementAndGet() inside the Mono.fromCallable() and then add the .subscribeOn(Schedulers.boundedElastic()) in the end.


}

}