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Add null check for consumer in MessageListenerProxy #219

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Merged
k2la merged 2 commits into from
Jul 12, 2022
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Add null check for consumer in MessageListenerProxy #219

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Add null check for consumer in MessageListenerProxy
BewareMyPower Jun 14, 2022
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BewareMyPower Jul 8, 2022
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6 changes: 5 additions & 1 deletion src/Consumer.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -63,7 +63,11 @@ void MessageListenerProxy(Napi::Env env, Napi::Function jsCallback, MessageListe
Consumer *consumer = data->consumer;
delete data;

jsCallback.Call({msg, consumer->Value()});
// `consumer` might be null in certain cases, segmentation fault might happend without this null check. We
// need to handle this rare case in future.
if (consumer) {
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@gaoran10 gaoran10 Jun 21, 2022 •
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Do we need to print some warning messages when the consumer is a null value?

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@BewareMyPower BewareMyPower Jun 21, 2022

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No. The initial value is null. And I found the NodeJS wrapper never logs any message. Even if you added a log here, there is still helpless to find in which scenario consumer is null here.

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@gaoran10 gaoran10 Jun 23, 2022

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I'm not sure if users lose to handle some messages when the consumer is null.

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@BewareMyPower BewareMyPower Jun 23, 2022

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I think the controversial point is whether should we skip the null consumer.

  • Yes: might lose messages (not sure)
  • No: fast fail

Adding logs doesn't solve anything. There is no logger in NodeJS client, printing logs to console is meaningless and helpless as I said.

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@BewareMyPower BewareMyPower Jun 23, 2022

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We need more info to reproduce the segmentation fault. But for now, a safe solution is to avoid accessing a null consumer.

jsCallback.Call({msg, consumer->Value()});
}
}

void MessageListener(pulsar_consumer_t *rawConsumer, pulsar_message_t *rawMessage, void *ctx) {
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