Given backend, which processes user requests of reading container logs(with follow option). Following approach is used:
Future<?> f = threadPool.submit(() -> {
try {
while (logStream.hasNext()) {
LogMessage msg = logStream.next();
String text = StandardCharsets.UTF_8.decode(msg.content()).toString();
emitter.send(SseEmitter.event().data(text).name(msg.stream().name()));
}
emitter.complete();
} catch (Exception ex) {
emitter.completeWithError(ex);
}
});
Where threadPool is just a Executors.newCachedThreadPool() and emitter is Spring's SseEmitter.
The problem is: when user no longer wants to read logs, he just closes the connection, but this thread is still running(execution is blocked in logStream.hasNext() which is calling InputStream.read(..)).
As far as I understand, hasNext() will never return false(at least while container is running properly), so this loop is endless, and we need to stop it somehow. Possible solution I tried:
emitter.onCompletion(() -> {
f.cancel(true);
});
was not successful. No InterruptedException was thrown.
Question: Is there any way of unblocking thread? Or maybe there is another approach of solving this problem (i.e. have a possibility to stop waiting for logs)?
